Recent Research on Sedimentology, Stratigraphy, Paleontology, Geochemistry, Volcanology, Tectonics, and Petroleum Geology

The Sabkha of El Breij has yielded the oldest marine Eocene vertebrate fauna from the Sahara Desert in southwestern Morocco. Fossils come from three distinct layers in the Samlat Formation sequence. Selachian teeth are abundant at all levels. The selachian assemblage in the lower level indicates a Lutetian-early Bartonian age. The selachian taxa of the two upper levels indicates an upper Bartonian age. The lower horizon yields abundant fossil remains of two protocetids, the very large Pappocetus lugardi and a smaller medium-sized protocetid. Protocetids are associated with rare remains of bony fishes, turtles, crocodyliforms, and a paleophiid snake (cf. Palaeophis moghrebianus). The two upper fossiliferous levels (Bartonian) are about 20 m above the lower level. They yielded remains of three genera of Basilosauridae: Chrysocetus, Platyosphys, and Eocetus, associated with abundant chondrichthyans, and remains of bony fish, turtles, crocodyliforms, and seabirds. Turtles are represented by a pleurodire species of the subtribe Stereogenyina, probably Cordichelys antiqua, and another pleurodire form remains to be determined. The crocodile vertebrae show that it is a Eusuchian, and the shape of the quadrate suggests a gavialoid. The two specimens of pseudotoothed birds (Odontopterygiformes, Pelagornithidae) are tentatively assigned to the genus Pelagornis, which together with Pelagornis from the Bartonian of Gueran constitutes one of the earliest records of this genus.

Stable isotopes of carbon and oxygen (δ13C and δ18O) archived in fossil tooth enamel are essential tools to reconstruct the palaeoecology and palaeohabitat of mega-herbivores. Among the mega-herbivores, hippopotamus (Hippos) are the third-largest existing artiodactyls. The family Hippopotamidae consists of semi-aquatic, mostly herbivorous non-ruminant animals. Hippos first appeared in the late Miocene (~ 6 Ma) which was the time of substantial faunal turnover and expansion of C4 vegetation in low latitude regions globally, due mainly to lowered atmospheric CO2 as well as other environmental factors. However, studies regarding the habitat of mega-herbivores are inadequate. In this paper, we reconstruct the habitat of Hexaprotodon sivalensis recovered from the early Pleistocene (ca. 2.5–2.2 Ma), Pabbi Hills locality of the Siwalik sub-Group of Pakistan. We used bulk stable isotope analyses of oxygen and carbon which provide temporal and environmental information on the animal’s ecology and diet. The average δ13Cenamel and δ18Oenamel are − 0.6 ± 1.4‰ and − 2.1 ± 2.1‰, respectively, which indicate that during the early Pleistocene, the diet of H. sivalensis was dominantly composed of C4 vegetation which was present mainly in the form of open grasslands. The high δ18Oenamel values indicate that H. sivalensis inhabited freshwater ponds under drier climatic conditions where they fed upon the C4 vegetation exclusively. However, enamel thickening/complexity and high crowns also provide direct evidence for pure C4 grass-dominated vegetation along with higher δ13Cenamel in the Siwaliks, like modern hippos from Africa.

The Al Bashair Formation corresponds to the lowermost part of the Andam Group (Haima Supergroup) that crops out in the Huqf region of central Oman. Al Bashair Formation is an important deep hydrocarbon-producing subsurface reservoir in the interior Oman Salt Basin. The current outcrop-based stratigraphic and facies analysis of the Al Bashair Formation in the Huqf region has shed new insights to better understand the spatial and temporal distribution of the depositional facies and construct a reliable depositional model. The results have shown that the Al Bashair Formation can be divided into two informal members. The lower informal member contains ca. 120 m thick interval of thinly interbedded (ca. 5–25 cm) sandstone, siltstone, and red mudstone packages with (ca. 1 m) carbonate layers. The mudstones sometimes exhibit the presence of desiccation mud cracks. The sandstones show different body fossils, such as trilobites, brachiopods, and echinoderms, trace fossils and halite molds. The carbonate layers include stromatolites and oolitic grainstones. The oolitic grainstones show the presence of herringbone cross beddings. The upper member of the Al Bashir Formation contains about 160 m thick interval of coarsening upward cycles of red mudstones, siltstones, and sandstones. The sandstones lack body fossils and show less frequent trace fossils including Cruziana and U-shape (Arenicolites) borrows. The sandstones show the presence of hummocky and swaley cross-stratifications. The described rock intervals of Al Bashair Formation support deposition in tide- and frequently storm-dominated shallow marine ranging from supratidal to subtidal settings.

The Amin Formation, the lowermost part of the Mahatta Humaid Group (Haima Supergroup), is a tight oil-producing reservoir in the interior Oman Salt Basin. It is exposed in the Huqf region of central Oman and was previously interpreted as braided fluvial, aeolian, and dry sabkha deposits. This study is an outcrop-based stratigraphic and facies analysis to furnish new insights into the Amin Formation in the Huqf region to understand the spatial and temporal distribution of the depositional facies and interpret the depositional environment. The results have shown that the formation can be stratigraphically divided into three informal members. The lowermost member is poorly exposed and comprises intervals of red to reddish-green claystones and siltstones enclosing greenish-gray, very fine-grained sandstone lenses. This member grades upward into brown, fine- to medium-grained, trough cross-bedded sandstone. The member fills relatively low topographic depression on the underlying Huqf Supergroup surface and lacks marine signatures reflecting deposition in an isolated inland freshwater lake. The middle member comprises intervals of cobble conglomerates grading upward into pebbly to granule sandstones, coarse-grained sandstones, and rarely, siltstones and claystones. The conglomerates are clast- to matrix-supported of large-scale, trough- to tabular cross-bedded, exhibiting a low relief erosional base. The interbedded pebbly to granule sandstones contain cosets of high- to low-angle trough and tabular cross-bedding with pebble lags at the bottom. The claystone, occasionally intervening in the sandstone, is yellow and parallel-laminated, enclosing lenticular-shaped bodies of siltstones. The erosional scours with lag deposits, fining upward trends, and lack of marine features indicate deposition in braided channels where the mudrocks represent overbank, floodplain, and crevasse splay. The uppermost member is fine- to very fine-grained sandstone interval with trough and tabular cross-bedding, ladder to wave ripples, and horizontal (Cruziana-like) to inclined (Psilonichnus-like) trace fossils reflecting deposition in shallow marine conditions. There are also localized transverse dunes of very fine- to fine-grained sandstones comprising cosets of medium to high-angle planar cross-bedding with current ripples reflecting their deposition as aeolian dunes. The Amin Formation can be envisaged as a complex system that is graded from an inland freshwater lake to fluvial (lower two members) and shoreface environments with subordinate coastal aeolian dunes in its upper member.

The Upper Cretaceous Muti Formation of the Aruma Group was the first unit deposited in the Oman foreland basin in the Oman Mountains. The Oman foreland basin is a major hydrocarbon-producing basin with great future exploration potential. A few studies were published in the early 1990; however, no detailed work on the sediments of the Muti Formation has been done since then. The closure and compression of the southeast margin of the Tethys Ocean during the Upper Cretaceous resulted in thrusting and obduction events and erosion of the Arabian platform, known as the Wasia-Aruma break. The Semail Ophiolite and Hawasina Complex were obducted over the eastern margin in northeast Oman, and the platform drowned, flexed, and faulted, resulting in the foreland basin development. The Muti Formation is well exposed around the Jabal Akhdar Dome, and a total of 14 outcrop sections are measured and described to identify the lithofacies associations and depositional setting of the formation. These lithofacies are correlated across various sections to help understand their distribution and depositional environments. The Muti Formation thickness ranges from 13.4 to 179 m and comprises nine lithofacies. These lithofacies are grouped into four lithofacies associations, namely wackestone to mudstone, monomictic conglomerate, laminated claystone, and ferruginous clays. Based on these results, the formation is lithologically subdivided into a lower and upper parts. A diverse fossil assemblage was observed within the wackestone to mudstone lithofacies, including ammonites, bryozoans, bivalves, brachiopods, and gastropods. The Muti Formation records the transition from a passive margin to a foreland basin deposited in a shallow marine environment. The lower part is dominated by wackestone to mudstone lithofacies association rich in fossils accumulated in the middle carbonate shelf. The upper part of the formation is composed of siliciclastic lithofacies deposited on the outer shelf under low energy conditions. The findings of this study shed light on the lithofacies distribution and depositional system of the Muti Formation across the foreland basin.

The Miqrat Formation is the uppermost lithostratigraphic unit of the Mahatta Humaid Group (Haima Supergroup) that crops out in the Huqf region of central Oman. The formation is among the complex, deep tight gas reservoirs in the interior Oman Salt Basin. The formation has been previously interpreted as deposits of interconnected ephemeral playa lakes, aeolian dunes, and wet and dry sabkha environments. Lithologic reevaluation of the rocks in the Huqf region unveils new geologic information that allows reassessment of the spatial and temporal distribution of the depositional facies and the construction of the updated and improved depositional model. The Miqrat Formation can be stratigraphically divided into three informal members. The lowermost member is about 80-m-thick section characterized by coarsening-upward cycles of dark brown to reddish-brown mudstones to sandy siltstones that grade to fine-grained sandstones. The sandstones show parallel to low-angle cross lamination and wave ripples, whereas the mudstone and siltstone interbeds display large-scale desiccation cracks. The middle member contains about 40-m-thick light-brown to buff, fine- to coarse-grained sandstone containing low- to high-angle tabular to trough cross-bedding and wave ripples. Near the uppermost part of this unit, the sandstone contains Thalassinoides trace fossils, which are reported here for the first time, indicating the deposition in the marine system—subtidal environments. The uppermost member of the formation is poorly exposed interval and lithologically appears to be similar to that of the lower member. The sedimentary properties and trace fossils suggest that the formation accumulated in a marginal marine setting characterized by tidally-influenced supratidal to intertidal environments (lower and upper members) and subtidal (middle member) depositional setting. This interpretation may further indicate a possibly 3rd-order sea level change represented by initial low sea level (lower member) through relatively higher sea level (middle member) and lastly back to lower sea level (upper member).

The Barik Formation corresponds to the uppermost part of the Andam Group (Haima Supergroup) and is well exposed in the Huqf region of central Oman. It is a complex, deep, tight gas reservoir in Oman’s interior Salt Basin and has been previously interpreted as braid delta deposits. This study illustrates a detailed outcrop-based stratigraphic and facies analysis of the Barik formation in the Huqf region. It offers new insights into the spatial and temporal distribution of the depositional facies and provides more information to enhance the depositional environment interpretation of the Barik Formation in the outcrop. The results revealed a complex depositional system indicated by various lithofacies, which have been grouped to represent four facies associations, including (i) mouth bar/shoreface, (ii) tidal flat, (iii) tidal channel, and (vi) delta distributary channels. The mud drapes, large-scale reactivation surfaces, sigmoidal cross-bedding, climbing ripples, and flaser bedding indicate tidal flats and delta distributary channels of the lower delta plains. Wave and storm facies, including wave ripples and small-scale hummocky cross-stratification, represent a mouth bar/shoreface of the delta front depositional setting. The presence of basal scouring surfaces with lag deposits at channel bases and desiccation cracks of red mudstones indicated fluvial and subaerial facies. This study serves as an analogue for the ancient hybrid energy prograding delta over a broad and low relief shelf in a vegetation-free system, where the deposition is controlled by an interplay of multi-related tidal, wave/storm, and fluvial processes.

The Barik Formation sandstones accumulated under a deltaic system and constituted important deep and tight gas reservoirs in the Interior Oman Salt Basin. This study aims to understand the genesis of grain-coating clays and their role in controlling the development of feldspar overgrowths. The study is based on integrated different analytical techniques, including thin-section petrography, scanning electron microscopes coupled with dispersed energy spectrometers, and X-ray diffraction analyses. These are achieved to determine the mineralogical and chemical composition, texture and mode of occurrence of the grain-coating clays. These analyses revealed that the grain-coating clays are typically illite and, to a smaller extent, chlorite. The observed illite forms ~ 5 μm thick envelop rimming partially to entirely the detrital grain surfaces and also along grain-to-grain contacts. The illite shows honeycomb-like texture and cornflake textures with filamentous terminations. The chlorite forms ~ 3 μm thick envelop rimming, seemingly the entire detrital grains and at grain-to-grain contacts. The chlorite also shows a honeycomb-like texture and curved platelet morphologies. The described illite and chlorite textural morphologies and mode of occurrence strongly support their growth through a transformation process from smectite precursors. The transformation of smectite to illite and chlorite were taken place during the mesodiagenesis. The smectite clay precursors are naturally near-surface clay fractions that are ultimately introduced mechanically into sandstones by hydrodynamic pumps during high tides. The larger extent of illite compared to chlorite can be related to the enrichment of the system by potassium ions, which are sourced internally via the widespread dissolution of detrital potassium feldspar grains. It is noticed that when the illite and chlorite, partially to entirely, envelop the detrital feldspar grains, they effectively hinder and inhibit the precipitation of authigenic feldspar overgrowth by limiting the nucleation sites on the detrital grains. This study may be regarded as an analogue for similar sandstone reservoirs to understand better the genesis and role of grain-coating clays on reservoir quality.

Seismic reflection profiles that were shot along the Levant Basin and its eastern margin show considerable thickening of the Oligo-Miocene sequence shelf-to-basin transition compared with overlying and underlying stratigraphic units. Numerous erosional channels were depicted in that sequence, suggesting a massive flow system of sedimentary supply from the source in the east to the sink in the west. The dimensions of these channels vary, but together they form a dense submarine system of sediment transport. Reconstruction of the Oligo-Miocene land-to-sea drainage system, from northwestern Arabia to the Mediterranean Sea, was active before the tectonic evolution of the Levant Rift and its uplifted flanks. Consequently, analog experiments showed that the tectonic evolution of the rift under the tectonic regime of oblique extension would generate a simultaneous break-up of detached series of discrete structural basins, which would interconnect gradually. That gradual connection enabled the westwards sediment supply concurrently with the structural evolution of the Levant Rift, but during the late Miocene and the early Pliocene, the growth of the rift and its elevated flanks gradually truncated the westwards fluvial flow. Since the middle Pliocene, only small rivers were left behind to supply Levantine sediments to the Mediterranean, and at present, the Levant Basin derives most of its sediments from the Nile River.

The Cryogenian Snowball Earth episode is represented in Oman by the Fiq Formation of the Abu Mahara Group. Although the Fiq Formation is an important hydrocarbon target in Oman, its spatial and temporal depositional facies distribution is still poorly understood. This study aims to build on previous outcrop studies and develop a depositional model based on detailed sedimentological logging of the well-exposed Fiq Formation in the Jabal Akhdar area of northern Oman. This study has revealed that the Fiq Formation is of glaciomarine (i.e., proximal and distal) and proglacial facies. Proximal glaciomarine facies consist of discontinuous, thin, clast-rich diamictite intervals. The clast-rich nature suggests rainout diamictites formed by the continuous source of debris below an ice sheet, extending some distance from the grounded ice margin. Distal glaciomarine facies make up most of the logged section and consist of thick massive mud-prone, clast-poor dilute diamictite intervals. They are of rainout ice-rafted based diamictites, sourced by iceberg-based debris flows, and deposited towards the distal area of the basin, distant from an active ice margin. Local glacier features (i.e., ice-rafted granitic dropstones) display clear evidence of active glaciation during the deposition of the Fiq Formation. The proglacial, gravity flow elements comprise gravity flow facies consisting of massive, locally graded sandstones with rippled tops, displaying pulse-like features, representing bottom-current-based turbidites, sourced from meltwater bottom-currents from sub-glacial tunnel-mouth outlets, and deposited on unstable slope setting. Proglacial, gravity flow facies are also represented by parallel and thinly laminated siltstones and deformed mudstones, massive pebbly sandstones and clast-supported conglomerates with moderate to well-sorted texture, and rippled fine-grained sandstones and siltstones. Altogether this suggests suspension fallout from turbid plumes, intensively reworked debris and dilute current-based ripples formed in a deep water setting. Thick intervals of structureless sandstone represent lithofacies deposited in a braided fluvial environment. The Fiq Formation represents cycles of sea-level rise and fall events formed during local and multiple glaciation and deglaciation events. The outcome of this study may serve as a reference to test Fiq’s potential development as a play and to define its regional variation in further studies.

The Castellón B-1, 2, 3, 4, 11, and 12 cores were studied to establish the precise age and the stratigraphic framework of the Cenozoic offshore sedimentary succession from eastern Iberia. Six stratigraphic units were recognized: (i) a Black Sandstone Unit, (ii) a Red Beds Unit, (iii) the Alcanar Conglomerates, (iv) the Tarraco “Shale,” (v) the Amposta Limestone, also known as “Amposta Chalk,” and (vi) the San Carlos Group. The Black Sandstone Unit corresponds to non-fossiliferous slightly foliated fault breccias that resemble the Carboniferous Scala Dei Formation cropping out in the Priorat area (onshore Catalonia, NE Spain). The Red Beds Unit consists of fine-grained sandstones and red clays containing Classopollis sp. pollen grains, which range from the Late Triassic to the Paleocene. According to the known stratigraphy of onshore deposits from eastern Iberia, they are comparable with the red beds of the uppermost Cretaceous-Paleocene Mediona Formation. The Alcanar Conglomerates are mainly made up of Paleozoic clasts indicating the existence of nearby subaerially exposed Paleozoic rocks. The Tarraco “Shale” is made up of siliciclastic-influenced wackestone-packstone textures with planktonic foraminifera. Above, the Amposta Limestone comprises platform carbonates rich in coralline red algae, as well as larger benthic foraminifera including Borelis sp., Heterostegina sp., Amphistegina mammilla, and Amphistegina bohdanowiczi. The foraminiferal association suggests an early-mid Langhian age. The drowning of the Amposta Limestone is marked by the deposition of the planktonic foraminifera-rich deposits of the lower part of the San Carlos Group.

The Kulyumbe River section (NW of the Siberian Platform) is one of the most complete, best exposed, well-studied, and relatively easily accessible Cambrian-Ordovician (Cm-O) successions on the entire Siberian Platform. It is a key section for regional correlation of the Furongian-lower Ordovician interval in Siberia. However, the exact position of the Cm-O boundary as well as the boundaries of the global Ordovician stages in the section is still a matter of debate. We present new magneto-, chemo-, and biostratigraphic data, which allow us to discuss the position of the Cm-O and Tremadocian-Floian boundaries in the Kulyumbe River section. These data determine a new confident levels for correlation of transitional Siberian Cm-O layers with the International Stratigraphic Scale.

Carbonate platforms flourished in the Maestrat Basin (E Iberian Plate) during the Aptian recorded two episodes of major sea-level fall. The sedimentary results of lowering sea level during the Aptian were studied in two sub-basins of the Maestrat Basin, namely, Galve (in the western margin) and Morella (in the northern margin). The oldest episode occurred within the Dufrenoyia furcata ammonite zone, during the late early Aptian, whereas the youngest event had an early late Aptian age and occurred around the boundary between the Epicheloniceras martini and Parahoplites melchioris ammonite zones. The sedimentary evidence of such drops in sea level includes erosional, locally incised, subaerial unconformities with paleokarst developed at the platform tops. The amplitudes of sea-level fall are estimated to be in the order of 50 to > 100 m and were measured from the depths of the incised valleys recorded. There are no angular stratal relationships between the truncated sedimentary successions and the incised valley fills. Therefore, these drops in relative sea level are interpreted to be mainly of eustatic origin. The late early and early late Aptian sea-level drops occurred respectively in < 0.9 and < 3 Myr according to the current version of the Geological Time Scale. Such amplitudes (> 10 m) and durations (< 0.9 Myr) of relative sea-level fall and subsequent rise are considered rapid in geological terms, and thus could be the result of glacial eustasy. Nevertheless, clear sedimentological, paleontological, and/or isotopic evidence of significant portions of Earth’s surface covered by extensive ice sheets during the Aptian has not been reported so far.

This research is a continuation of the previous biometrical study of the Eocene macroids in Dalmatia (southern Croatia), with the aim to determine the principal bioconstructors and reveal the composition and distribution patterns of macroids during the Paleogene Period. We randomly collected 322 samples of extracted macroids and 12 samples of host rocks, from the beaches between Omiš and Mimice in Dalmatia. Thin sections were prepared at the University of Zagreb/Faculty of Science, studied and photographed using a light microscope with camera. Macroids occur within the Eocene “Nummulitic” packstones, floatstones to rudstones, dominated by the large benthic foraminifera, a common facies of ramp crests, deposited along the coasts of the Tethys Ocean. Algal-dominant genera are Sporolithon and Lithoporella. Among the encrusting foraminifera, Acervulina and Solenomeris prevail. Serpulids, corals, bryozoans, echinoids, crinoids, and other biota also occur as bioclasts, but they are less abundant. Regularly shaped macroids can be classified as rhodoliths, as they are dominated by the genus Sporolithon. Irregularly shaped macroids were formed by the intercalation of red algal and encrusting foraminiferal layers, pointing to the slightly deeper depositional environment. The subsequent demise of green and then red algae, and their replacement with encrusting foraminifera during the Paleogene can be correlated with the basin subsidence and/or increased turbidity, a scenario related to the Alpine tectonics in this area.

Chemosymbiotic bivalves are rare and specialized biota, able to survive in hostile environments. We recorded their presence in the Middle Miocene (Badenian—Langhian/Serravallian) deposits of Northern Croatia. Bivalve specimens, representatives of the families Solemyidae (11 specimens) and Lucinidae (998 specimens), are in most cases preserved as casts and molds. Newly collected specimens (10 lucinids and 2 solemyids) were cleaned up, determined, and housed at the Croatian Natural History Museum and the University of Zagreb, Faculty of Science. Lucinid bivalves are widely dispersed and comprise several taxa, including the most numerous Lucinoma borealis (Linnaeus, 1767), particularly common Lucina (Eomiltha) polymorpha Kochansky, 1944 and Megaxinus ellipticus (Borson, 1825). They were found in deposits of different lithologies, varying from argillaceous marls to limestones. Lucinids are generally considered the most diverse among the chemosymbiotic bivalves, and are widely distributed in various habitats. Some of the collected lucinids lived in the shallower marine, oxygen-depleted environments. We also recorded solemyids and lucinids together with planktic molluscs (pteropods) pointing to the deeper marine environments. The age of the deposits comprising these findings coincides with the Langhian opening of the marine corridors between the Paratethys and the Mediterranean during the highstands, a major faunal turnover event in the Central Paratethys and Miocene Climatic Optimum. Records of chemosymbiotic bivalves and accompanied fauna in the investigated area could point to the further diversification of the Badenian marine environments in this part of the Central Paratethys and their correlation with similar contemporaneous environments and fauna in the Mediterranean.

Some new mammalian remains have been discovered in the new localities (Kangar, Dhilomora, Rasool pur, Nikki Rawal Wali) of the late Pliocene (3.5–2.58 Ma) of the Siwalik sub-group, Pakistan. This work describes the comprehensive systematic and taxonomic investigations of new fossils comprising molars and nasal horns belonging to three families including Bovidae (Kobus porrecticornis), Anthracotheriidae (Merycopotamus dissimilis), Rhinocerotidae (Rhinoceros sondaicus). The present study adds to the scanty data of Pliocene mammals of the Siwalik sub-group of Pakistan. Taxonomic and morphological studies of these new fossils give a novel insight to the dietary habitats of the late Pliocene fauna as higher hypsodonty indices and complex dental patterns indicate a coarser and tougher diet available to these mammals which coincide with the hypothesis of grasslands expansion after the famous late Miocene climatic and vegetational change in low-latitude regions, worldwide.

Evaporite formations may represent suitable subsurface storage sites for carbon, nuclear waste, and Geo-energy applications, which are key for the Energy Transition. Consequently, the systematic indexation of the knowledge on evaporite structures is key for developing geoscience-based technologies to address the pressing societal challenges. However, vast amounts of subsurface and surface data about the stratigraphy, structure, petrophysics, and geochemistry of evaporite structures are often segregated, not systematically organized, and, sometimes, inaccessible. The Iberian Evaporite Structure DataBase (IESDB; https://iesdb.eu ) is a collection of 150 inventoried evaporite structures in Spain and Portugal, constituting the first comprehensive assessment from any region of the world that is focused on these type of structures. The IESDB is sourced from more than 1500 published and unpublished references and databases and includes varied information and figures of undeformed evaporite successions, outcropping and buried diapirs, evaporite-cored anticlines, evaporite-detached thrusts, and allochthonous bodies. Compiled data include key bibliographic references and a complete summary of the structure, stratigraphy, chronology, subsurface data, and mining activity. The IESDB meets the FAIR principles of data management and is presented as an open-access webpage where indexed structures can be selected by a multi-criteria search engine or visualized in an interactive map. The information compiled in the IESDB represents an opportunity to boost the scientific research on Iberian evaporites to tackle important societal challenges, and it can also foster similar initiatives in other regions.

The Sahara Desert in southwestern Morocco is today an important paleontological region for its richness of archaeocete whale remains from the middle and late Eocene. Remains of Basilosauridae have been reported from Gueran and El Breij of the Bartonian age and Ad-Dakhla of the Priabonian age. There are no complete skeletons, meaning it is rarely possible to associate the skull and the post-cranial bones directly. However, analysis of the size and shape of the recovered sequential vertebrae enables distinction and comparison of the species of basilosaurids. Lumbar vertebrae best distinguish the different species of Basilosauridae, and eight different species are present in the three localities combined. Reexamination of the characteristics of the vertebrae of the different species of basilosaurids allows a better expansion of knowledge concerning their taxonomy, stratigraphic distribution, and paleogeography.

Fossil tooth enamel archives the isotopic variability during its formation, an essential tool to reconstruct the paleoseasonal changes during an animal’s life. Stable isotopes of carbon and oxygen from enamel (δ13Cenamel and δ18Oenamel) reveal an animal’s dietary and drinking preferences and are helpful in the reconstruction of paleoclimate and seasonality. The current study attempts to probe these paleoclimatic and seasonal changes during the Early Middle Pleistocene (2.5–1.6 Ma) and their impact on mammals of the Siwalik sub-Group of Pakistan using the intra-tooth analysis of Family Equidae for δ13Cenamel and δ18Oenamel (n = 87). The δ13Cenamel values of the Family Equidae (− 3.1 ± 1.3‰) indicate that the Pleistocene mammals consumed C4 diet (grasses) dominantly. Whereas, δ18Oenamel values of Equidae (0.2 ± 1.5‰) provide evidence for a dry and open habitat where animals were drinking from open evaporating water sources, most preferentially, ponds or streams. A positive correlation between intra-tooth δ13Cenamel and δ18Oenamel indicates that C4 grasses spread more under dry conditions. The higher variations in intra-tooth δ18Oenamel values (4–5‰) indicate an intense seasonal influence on the Siwalik floodplain. Our results conclude that the Early Middle Pleistocene time span (~ 2.5–1.6 Ma) in the Siwaliks was dominated by C4 grasses favored under the dry and highly seasonal climate, as revealed through the intra-tooth isotopic signals.

Phlogopite solid-solutions have a wide physico-chemical stability field; they are thus ubiquitous in a wide variety of geological environments. Phlogopite may provide important insight into the physico-chemical parameters of its crystalization conditions thus representing a tool for understanding magma storage conditions and petrogenesis. This paper focuses on the study of some intriguing single-crystals occurring within a lamprophyre minette from Fort Regent, St. Helier (Jersey Island, UK). The primary assemblage is represented by phlogopite + clinopyroxene + alkali-feldspar + apatite. Phlogopite occurs as both euhedral to subhedral phenocrysts and as euhedral microcrystals. Phlogopite phenocrystals associated with mica-lamprophyres generally present normal and continuous compositional zonings, however, the crystals from the studied minette are characterized by dark chestnut patchy cores enveloped by euhedral oscillatory rims. Preliminary results indicate (i) cores with a Mg# = Mg/(Mg + Fetot) of ≈ 0.73 and high TiO2 contents of ≈ 10%; (ii) inner rims having Mg# ≈ 0.90 with TiO2 not exceeding 2%; and (iii) external rims with Mg# ≈ 0.67 and TiO2 contents up to 5.5%. Combination of EMP and single-crystal FTIR results in the OH-stretching region shows that, differently to what observed in other occurrences, the substitution mechanism responsible for the exceptional Ti zoning during the biotite crystallization is the Ti-vacancy mechanism that is known to be typical of HP/HT crystallization environments.

Apatite is a common phosphate mineral in crustal rocks, recognized as being the main feedstock for fertilizer industry, but also due to its rich composition, which makes this mineral a source for rare earth elements. Moreover, apatite has a structure stability and durability under radiation conditions in geological situation and in synthetic products. Thus, britholite, which is a phospho-silicate-apatite-containing rare earth elements, is considered as one of the possible candidates for actinides and fission products immobilization. Hence, the management of apatite, in this environment protection view, suggests the knowledge of their stability, thermodynamic properties, dissolution, and potential reactions. The calorimetry of dissolution is a powerful technique to study the stability of materials in various solvents, like water and acid solutions, which leads to the determination of numerous thermodynamic values. In this work, the thermochemical stability of an apatite solid solution was studied, named Neodymium-bearing silicate-oxyapatite or britholite Ca10−xNdx(PO4)6−x(SiO4)xO having different substitution rate x, with 1 < x < 6. The calorimetric study consisted of measuring the enthalpies of a solution in nitric acidic aqueous solution (46% w) at 298.15 K using a swinging differential Tian-Calvet calorimeter. The formation enthalpies from the elements were reached by a thermochemical cycle and complementary experiments. Moreover, the mixing enthalpies in the studied solid solution were also deduced. The results revealed that the solution reactions are exothermic and display a notable increase of the absolute values of energies with the rate of substitution. Furthermore, the mixing enthalpies are positive and the formation enthalpies are decreasing with the amount of substitution x. Such experimental results are readily usable thermodynamic data for geochemical studies on the stability of apatite.

Fly Ash and Bottom Ash (FABA), a waste product in the form of ash from the burning coal at coal-fired power plants, is considered to have many advantages as the raw material for construction. One of the construction product examples is a geopolymer. This research aimed to determine the effect of the FABA characteristic on the compressive strength of geopolymer products. The source of fly ash (FA) used in this study is FA from Tanjung Jati B combustion power plant, Java, Indonesia which was characterized using petrographic analysis, XRD analysis, XRF analysis. Geopolymer was made with wet mixing methods and characterized using compressive strength tests and FTIR analysis. This study characterized the fly ash as having the dominant major oxides being Al2O3, SiO2, and Fe2O3. The inorganic components consist of glass, quartz, mullite, k-feldspar, fe-spinel, mg-spinel, hematite, magnetite, calcite, and kaolinite, while the inorganic components are dominated by glass materials, and the organic component consists of unburned coal (UC). Geopolymer, which is made, has a compressive strength average of 33 Mpa. A high value of SiO2/Al2O3, a high value of reactive SiO2, a low value of unburned carbon, and a low value of Fe2O3 affect the bond structure formed in the geopolymer and have a direct effect on increasing compressive strength. The results of this study could be used as a guide for determining the initial characteristics of FA in the manufacture of geopolymers with maximum quality.

Fly ash and bottom ash (FABA) are residual products from a power plant coal combustion that can be processed into products with economic value. One component of FA that has the potential to proceed is the cenospheres. However, the concentration of cenospheres in FA is limited so further analysis is needed to maximize this potential. The study was conducted using FA samples at Tanjung Jati B combustion power plant covering units 1 and 2, unit 3, and unit 4 located in Jepara, Central Java, Indonesia. Samples were analyzed to determine the composition of FA and the concentration of cenopsheres within. The main oxide compounds in FA were determined by XRF analysis. The organic and inorganic components of FA were identified through petrographic observations. The mineralogical composition of FA was generated by XRD analysis. The cenospheres retrieval test used the sink-float method with three trials on each sample and the presence of the cenospheres was confirmed through SEM analysis. The results showed that the inorganic components of FA consist of glass, quartz, Fe-spinel, Mg-spinel, hematite, magnetite, mullite, kaolinite, smectite, K-feldspar, and calcite, while the organic component found in FA is Unburned Carbon (UC). The cenospheres concentration values obtained were in the global range of cenospheres concentrations. The relationship between the constituent components of FA and the concentration of the cenosphere indicates that the presence of quartz in the FA sample positively correlated with the amount of cenospheres that can be observed through petrographic analysis.

In this paper, we present a draft new experimental setup for studying the sublimation of water ice at low temperatures under different conditions. The sublimation temperature could be varied from − 196 to 0 °C. Also, the unit is connected to an Isotope Ratio Mass spectrometer (IRMS). An isotopic mass spectrometer allows measuring the isotopic composition of vapors of an evaporating substance and the rate of sublimation under specified physic-chemical conditions. The gas input into the mass spectrometer on-line mode distinguishes the developed setup from the existing analogues. The developed setup is equipped with a transparent quartz window through which the surface of the test substance can be heated using a halogen lamp. The setup can also be used to study the sublimation of gas hydrates and CO2, to study the sorption of gases on the surface of various samples.

We have updated the standard method for estimating the amount of carbonates in carbonaceous chondrites on the example of the Murchison meteorite (CM2). In contrast to the existing technique (passing carbon dioxide released from carbonates through brine and weighing the remainder of the substance, when a small volume of gas may be too small for analysis using a mass spectrometer, our method is more reliable because all carbonates are collected in the form of a precipitate and then decompose at once at high temperature to carbon dioxide CO2 and divalent metal oxides. This required the creation of a laboratory setup and development of the technique to calibrate mixtures of (Volcano Tolbachik, Kamchatka, Russia) with pure calcium carbonate CaCO3 for analysis (from 0.1 to 1.0 wt.% with an interval of 0.1). The error estimation method was made on the basis of physicochemical calculations of the content of carbon dioxide gas in the installation air. Results are tested and confirmed using gas chromatograph.

The Lufilian Arc of Neoproterozoic formed during the Pan-African orogeny in the Democratic Republic of Congo and to its south-east in the Republic of Zambia, and the Westward extension of similar rock sequences into southern Africa. Due to the global demand for metal ores such as copper, cobalt, nickel, lithium, etc. which continues to increase for the foreseeable future, the needs of new technology (e.g., batteries for electronic devices and electric vehicles, etc.) and the desire and efforts to improve living standards worldwide are some of the key drivers which dictate the aggressive ongoing exploration and mining activities in the Democratic Republic of Congo. The Lufilian Arc is a zone known to hosting world-class high-grade Cu-Co-U and Pb-Zn mineralization. The use of soil geochemistry as one of the targeting tools in mineral exploration, especially in the search of copper/cobalt shallow and blind sub-outcropping deposits, has proven to be very successful and efficient at early stage of exploration. The purpose of this study aims at reviewing and demonstrating the effectiveness of soil geochemical exploration technique in the discoveries of different Cu-Co deposits, like Kibamba Cu-Co deposit of the Congolese Copperbelt. It has been observed that shallow-seated orebodies express anomalies in soils through dispersion processes over time. Mapping of chemical element signatures, identification of pathfinders, scavengers within in-situ soil covers, interpretation of regoliths (allochthonous vs. autochthonous), etc. in targeting of metal anomalies in soils and prioritization can help remarkably in revealing a presence of mineral bodies under cover. To reach our goals, a data summary of soil geochemistry at selected exploration areas within the Copperbelt where soil surveys were conducted at early phases of exploration, particularly at Kibamba area has been processed using MapInfo software combined to Discover for basic statistics and interpretation for a definition of orders of anomalism for priorities. Then, a follow-up by other exploration techniques such as geophysical surveys, structural and lithological mapping then drilling (reverse circulation and coring) to test and confirm anomalies have been complimentary for resources definition and estimates.

Salt water and dissolved salts themselves have been used in dermal therapies since ancient times. Dead Sea salts are the most known ones used for dermal curative and cosmetic proposes. Studies recognized their dermal application benefits in conditions such as psoriasis and eczemas. Elements (e.g., Na, Mg, K, Ca) present in salts can be absorbed by the skin, and aid in processes such as cellular respiration, or act as anti-inflammatory agents, among others. Therapeutical results could be enhanced with the presence of certain minerals. The present study aims to characterize the mineralogical and chemical composition of salts produced in Portugal saltpans of two different areas, Ria de Aveiro and Ria Formosa and a commercial coarse salt subjected to purification. Potential positive and negative outcomes by dermal applications are assessed in this study. Samples show chemical and mineralogical composition variation. Further laboratorial analysis and results interpretation are being conducted.

The NE-SW trending Central Indian Tectonic Zone (CITZ) is a prominent suture zone that was brought out by the amalgamation of the Northern Indian Block (NIB), constituted by the Aravalli-Bundelkhand craton in the north and Southern Indian Block (SIB), constituted by the Bastar-Singhbhum and Dharwar cratons to the south. The CITZ is traversed by major tectonic lineaments parallel to its length: the Son-Narmada North Fault (SNNF), the Son-Narmada South Fault (SNSF), the Gavilgarh-Tan Shear Zone (GTSZ), and the Central Indian Suture/Shear (CIS) from north to south. The study area located in the eastern part of Central India, near the GTSZ records different phases of granite intrusions. They are comprised mainly of two types of granite facies: coarse to medium-grained pink granite and medium to fine-grained gray granite. Pink granite are composed by K-feldspar, plagioclase, biotite with accessory hornblende, apatite, zircon, titanium-magnetite and garnet with rare muscovite, chlorite; whereas the gray granite is more enriched in ferromagnesian phases. Mineral chemistry data sets are used to constrain the physicochemical, pressure–temperature condition of magmatic origin and depth of emplacement of studied granite. Previous results from the study area were not subjected to the genesis and tectonic setting of these granites. Biotite composition with low MgO content (5.05–5.59) and high FeO (23.66–24.60) suggests iron enrichment, and the narrow range of the Fe2+/Fe2+ + Mg suggests their magmatic nature. The 10*TiO2–(FeOt + MgO)–MgO ternary diagram is used to determine the nature of biotite, where primary biotite is most likely affected by post-magmatic fluids. In the ternary diagram of FeOt–MgO–Al2O3, biotite compositions suggested that these granitic rocks are S-type with peraluminous characteristics and originated by syn-collisional tectonic setting. The ferromagnesian minerals of biotites composition fall in the Fe-rich siderophyllite field in the ternary plot (Alvı + Fe3+ + Ti)–Mg–(Fe2+ + Mn) and the FeOt/(FeOt + MgO) versus MgO (wt.%) correlation plot indicates a crustal source. The Ti content in biotite thermometry suggests crystallization at 716–730 °C at 4.24 to 5.57 kbar pressure. The biotites characteristics suggest the magma that initially derived from metasomatized crust through melting in plate interiors.

The Tirodi Gneissic Complex (TGC) from central India represents part of the basement gneisses. The TGC comprises a combination of pink and grey granitic gneiss assemblages, and it is petrographically characterized by biotite-rich granite gneisses. The geochemistry and isotope (Rb–Sr) data set is used to constrain the petrogenesis of TGC granitoids and Precambrian crustal evolution. Previous geochemical results from the study area were not focused on the genesis and crustal evolution of these granitoids. The present contribution addresses these issues by using new geochemical and isotopic data sets. The studied samples were analyzed by WD-XRF (Siemens SRS 3000) and ICP-MS (Perkin Elmer, Elan DRC-e) facility at Wadia Institute of Himalayan Geology Dehradun. These granitoids classified as calc-alkaline granite-trondhjemite with metaluminous to peraluminous composition. The negative correlation of ferromagnesian oxide with silica suggests primary magmatic igneous parental melt. Multi-element patterns for the TGC granitoids are characterized by large ion lithophile elements (LILE) enrichment, depletion in high field strength elements (HFSE: Nb, P and Ti) and positive Pb and Zr anomalies. Negative anomalies in HFSE correspond to crustal/lithospheric sources with some influence of K-feldspar, plagioclase and Ti-oxide fractionation. Isotopic data presents the Initial 87Sr/86Sr(t=1.6 Ga) ratio that varies from 0.70595 to 0.73191 for TGC granitoid. Such a range of initial 87Sr/86Sr ratios (> 0.706), corresponding to the TGC granitoid, indicate they are generated within the crust. The elevated value of the initial 87Sr/86Sr ratio may also correspond to the alteration. The geochemical results on the TGC granitoids indicate transitional tectonic settings from “within plate granite” to “volcanic arc syn-collisional granite”.

Pan-African granitoids of variable mineralogical compositions are emplaced in Kassa, Zing area, which form part of the Adamawa Massif of Northeastern Nigeria Basement complex. In this study, 16 samples obtained during fieldwork were subjected to geochemical analysis using XRF techniques in order to shed more light on the origin and tectonic setting of the rocks. Studied rock suites include ijolite, syenite, quartz syenite, quartz monzonite, biotite granite and granodiorite. The silica contents of the rocks range from 47.10 wt.% to 71.00 wt.%, exhibiting alkalic, calc-alkalic and calcic affinities. All the studied granitoids plot within the peralkaline and metaluminous fields on the A/NK versus A/CNK diagram. The decrease in Fe2O3T, MgO, CaO and TiO2 with increasing SiO2 and increase in Ba and Sr with increasing SiO2 is an indication of formation through fractional crystallization. Based on the field, petrographic and geochemical data, it can be inferred that the ijolite, syenite, quartz syenite, quartz monzonite and biotite granite are formed by the fractional crystallization of basic melts. On the other hand, plots of normative albite anorthite-orthoclase and Mg# versus SiO2 indicate that the granodiorite was emplaced via partial melting of tonalitic rocks from the deeper crust. In conclusion, the crystalline basement of Kassa area represents two different settings: Syn-collision and late orogenic stage. The oldest pluton, granodiorite, intruded during collision by partial melting of crustal rocks of tonalitic composition at temperatures between 850 and 950 °C. The emplacement of the ijolite, syenite, quartz syenite, quartz monzonite and biotite granite occurred during late orogenic times, via fractional crystallization of mantle-derived mafic melts.

The Nefza mining district in northern Tunisia comprises a wide variety of magmatic rocks related to the Cenozoic Mediterranean geodynamic history. Magmatic rocks consist mainly of granodiorite and rhyodacite emplaced during the Serravallian–Tortonian (14–8 Ma) and basalts emplaced during the Messinian (8–6 Ma). This magmatism belongs to the magmatic belt that extends along the Mediterranean coast of the Maghreb from eastern Tunisia to northern Morocco. The differences in geochemical composition were attributed to changes in mantle dynamics but the implications are still unclear in northern Tunisia due to the paucity of data. In this contribution, we present new bulk-rock geochemical data of the granodiorite and rhyodacite of Nefza recovered from OB45 drill core. Samples from the OB45 drill core give a unique opportunity to follow the geochemical evolution of the magmatic rocks with depth. Geochemical (major and trace elements) compositions of OB45 drill core rocks indicate a peraluminous and potassic nature. In the total alkali versus silica (TAS) classification diagram, samples plot in the rhyolite, dacite and trachydacite fields. Trace element compositions of Nefza magmatic rocks show typical subduction-related signatures, with relative depletion of high field strength elements (HFSE: Nb, Zr, Ta, Hf), large ion lithophile elements (LILE: Rb, Ba, Pb) and light rare earth elements (LREE: La, Ce, Nd, Gd, Sm), compared to the Continental Arc Andesite (CAA) geochemical composition. However, most of the OB45 drill core rocks show negative Eu anomalies. The wide geochemical composition of the igneous rocks emplaced during this tectonic evolution confirms a strong heterogeneity of the Mediterranean upper mantle composition. The comparison of the major and trace element as well as isotope characteristics of the magmatism in the Nefza and nearby regions (such as Kabylies and Sardinia) provides insights into the petrogenesis of the magmas and the nature of the main mantle source and its geodynamics.

The eastern part of Elba Island (northern Tyrrhenian Sea, Italy) is an exhumed sector of thinned continental crust, intruded by a monzogranitic pluton during the Messinian. Pluton emplacement occurred at a depth of c. 6 km as a consequence of permeability enhancement in the upper crust due to extensional tectonics. The contact aureole records coeval intense circulation of geothermal fluids and deformation. Here, we describe syn-tectonic amphibole + quartz veins that cross the contact aureole and are associated with extensional structures that formed during contact metamorphism. These veins (shear and extensional veins) are perpendicular or sub-parallel to the main foliation of the host rock and are either arranged in en-echelon arrays or developed in extensional jogs. Calcite, chlorite and titanite occur as accessory minerals in the veins. The interaction between hot fluids and host rocks produced localized metasomatism indicated by white haloes symmetrically developed adjacent to the veins. Fluid inclusions in quartz from amphibole + quartz veins are of two types: (i) two-phase liquid-rich and (ii) two-phase vapor-rich, in which the vapor phase includes mostly CO2 with minor amounts of CH4 and N2, the latter detected by Raman spectroscopy. Microthermometry indicates maximum temperatures of ~ 500 °C, assuming a maximum P of about 0.8 kbar and salinity up to 6.4 wt% NaCl equivalent, suggesting a metamorphic origin.

During the last decade, several studies have investigated the impact of diapirism in the diagenesis of the flanking sediments, as they are potential targets for the exploration of mining and energetic resources. These diagenetic processes are closely related to the tectonic evolution of the salt structures. The Tazoult and the Toumliline diapirs case studies display excellent exposures in the Central High Atlas (Morocco). Petrographic observations and geochemical analyses of Jurassic carbonate halokinetic sequences bounding both salt diapirs reveal similar diagenetic phases, which are: (1) saddle dolomites replacing both carbonate host-rock and fracture filling cements and (2) calcite cements and calcitized dolomite linked to meteoric water percolation. Coarse crystalline saddle dolomite (δ13C ranging from − 3.56 to − 1.79‰VPDB, and δ18O ranging from − 7.45 to − 5.19‰VPDB) are attributed to the circulation of hot Mg-rich brines in the vicinity of diapir structures during their passive growth. In contrast, meteoric percolation and the associated calcite cements, characterized by Mn content above 2000 ppm, and calcitized dolomite are attributed to later stages in the evolution of diapiric structures, most likely during their Alpine compressional deformation and inversion. Results indicate similar diagenetic evolution and geodynamic context to those described in other salt-related basins in the Tethyan domain such as in the Pyrenean Trough, Betic Margin, Cantabrian Basin, Iberian Basin, Causses Basin, and Tunisian Atlas Margin.

Data on radio-elemental abundances, radiogenic heat production and rare-metal affinity of acid volcano-plutonic rocks of Riwasa, Nigana, Dulheri, Dharan, Khanak, Dadam, Devsar and Tusham areas of Neoproterozoic Tusham Ring Complex (TRC) in the NW Indian Shield, are presented in this paper. Geochemically, the investigated rock types consist of hypersolvus to subsolvus, peraluminous and high-K calc-alkaline to shoshonitic A-type granitoids that are characterized by high SiO2 (59.56–75.73), K2O + Na2O (4.28–9.37), K/Na, Fe/Mg, Ga/Al, Rb/Sr, Th/U, Rb, Zr, Nb, Y, Th, U, REE (except, Eu), halogens (F & Cl) and low CaO (0.03–2.56), MgO (0.07–0.99), Sr, Cr, Ni, P and Eu in abundances. The enrichment of LILE (K, Rb, Ba) and HFSE (Zr, Nb, REE, Th, U), collectively, is attributed to high heat-producing (HHP) and rare-metal bearing granitoids. The acid volcanics of Riwasa and Tusham show wide variations of U (4.70–26.10 ppm), Th (19–145 ppm), Th/U (3.56–15.91), heat production (HP: 3.04–15.30 uWm−3), heat generation unit (HGU: 7.24–36.3 uWm−2) whereas the granitic massifs of Nigana, Dulheri, Dharan, Khanak, Devsar and Dadam show range of U (2.50–35.60 ppm), Th (17–124 ppm), Th/U (3.93–20 ppm), HP (3.03–16.63 uWm−3) and HGU (7.22–39.37 uWm−2), respectively. Moreover, the studied granitoids have much higher values of HP and HGU than the average values of continental crust (3.8 HGU), which indicate a ‘hot crust’ category and a possible linear relationship among the radioactive heat production, surface heat flow and crustal heat generation in the acid volcano-plutonic rocks of TRC. The elemental geochemistry and mineral chemistry in conjunction with radioactive element distribution (U, Th, K) suggest the possibility of important rare metals and rare earth metals (RMREM) mineralization, i.e., Sn–W, Nb–Sn, Sn–W–Be, porphyry Cu, U–Th and Rb–Ba, respectively, in the study areas.

Two large-scale mineralization events associated with two orogenies generated economically important iron formation-hosted hypogene high-grade iron orebodies in the Brazilian São Francisco craton each with distinctive fabric and chemical characteristics as genetic diagnostic features. During the 2.1–2.0 Ga Trans-Amazonian orogeny, magnetite–martite–hematite massive to banded orebodies from the Quadrilátero Ferrífero District in Minas Gerais were controlled by thin-skinned tectonic structures. Metamorphic fluids promoted leaching of gangue minerals and substitution of carbonates in the Paleoproterozoic Cauê Iron Formation of the Minas Supergroup to form the orebodies. The age of the Cauê IF is bracketed by the U–Pb SHRIMP date of 2580 ± 7 Ma for the youngest detrital zircons from the underlying quartzites and the Pb–Pb isochron date of 2420 ± 19 Ma for the overlying dolostones. During the Ediacaran to Cambrian Brasiliano orogeny, modified hydrothermal fluids of magmatic and metamorphic origin recurrently mineralized the Cauê IF and the younger, carbonate-free IFs of the Serra da Serpentina Group (1990 ± 16 Ma—MDA, U–Pb SHRIMP data), lower Espinhaço Supergroup along five events with ages of 497, 508, 518, 526, and 536 Ma related to granitic intrusions. Massive Ti- and Mn-rich magnetite orebodies from the Guanhães Tectonic Block formed at the contact zone of anatectic pegmatite intrusions in deep to intermediate crustal level. Schistose platy to granular hematite orebodies crystallized in thrust fault-related shear zones at the eastern border of the Espinhaço Fold and Thrust Belt by structurally controlled hydrothermal fluid flow. Mineralogical, chemical, and textural transformations of the Cauê Iron Formation during the first regional event were partially overprinted or obliterated by the far-reaching effects of the Brasiliano orogeny. The complex multistage evolution of schistose ore crystallized in shear zones has been tracked by micro-chemical, geochronological and EBSD petrofabric studies in the terrains eastern of the Espinhaço Range indicating a syn-deformational origin with the development of a crystallographic preferred orientation by crystal-plastic processes and hydrothermal fluid-assisted grain growth along thrust planes.

The North West Province of the Republic of South Africa is famously known for its mineral wealth in chrome and platinum group metals associated with the Bushveld Igneous Complex. In addition to this, small-scale supergene manganese deposits are found to occur on the weathered upper crust of the Neoarchean Malmani dolostones in the Transvaal Supergroup. These deposits occur as manganese nodules, wad and crusts confined to karstic depressions, which resulted from surficial weathering and dissolution of the underlying manganiferous dolostones. This study presents the geochemistry (X-ray fluorescence and inductively coupled plasma mass spectrometry analyzed sample data) of rare-earth (REE) and trace (TE) elements and its indicative role in constraining the genesis of the North West Deposit. The ore mineralogy consists predominantly of high valence state (Mn4+) Mn oxide minerals. These minerals are known to be scavengers of relatively high concentrations of trace (TE) and rare-earth elements (REE) into their tunnel crystal structures during mineral precipitation. The stability and coherent nature of these elements in natural environments have shown in their robustness when it comes to discriminating various sources of manganese ore substances. The Post-Archean Australian Shale (PAAS) normalized REE patterns of the ore samples indicated enrichment in Ba, Y, Cu, Sc, Ni, Cu, Co and other TE such as Ce, La and Zr and depletion of Zn, Nb and U. The REE + Y anomalies from the analyzed ore samples further indicated ore-enrichment in light rare-earth elements and notably pronounced positive Ce and negative Y anomalies indicative of hydrogenetic precipitation as a governing mechanism for the formation of manganese nodules. This was supported by the observation on the high field strength (HFS) element discriminating plots; Ce anomalies and YSN/HoSN, Ce anomalies and Nd concentrations and the Fe + Mn + (Co + Ni + Cu)*10, which effectively discriminate between hydrogenetic, hydrothermal, diagenetic and mixed source ore precipitates. An overlap in the normalized REE-Y patterns for Mn nodules and Malmani dolostones is suggestive of a close genetic relation.

Small Cu–Fe–Zn VMS deposits are widespread in Tuscan ophiolites (Ligurian Units). Industrial production was small and definitively ceased from the 1960s. Locally, massive ore (chalcopyrite-bornite-chalcocite) having exceptionally high grade was found. The Montecatini Val di Cecina mine exploited the largest “bonanza” and, for few decades in nineteenth century, became one of the richest and most profitable copper mines in Europe. This study (PRIN-MUR-2017AK8C32 project) was performed in order to define the structural setting, the potential for precious-critical metals and the redox reactions involving sulfides and gangue silicates. Ophiolite-hosted Cu–Fe–Zn ores in Tuscany mostly occur in serpentinite crosscut by dykes-laccoliths of gabbro and dyke-swarms of basalt. Chalcopyrite stockworks are common but the largest deposits are hosted by cataclastic shear-zones in serpentinite-gabbro basement and at the contact with the overlying basalt. The early chalcopyrite stockworks were strongly mechanically chemically reworked with formation of chalcopyrite-bornite-chalcocite nodules embedded in a chlorite, Ca-rich amphibole, Fe-rich serpentine, quartz, andradite and xonotlite assemblage. The ores contain substantial amount of sphalerite and pyrite and ubiquitous grains of clausthalite, native tellurium and gold, in accordance with the significant Te–Se–Au content of these deposits. The overall characters of the Cu–Fe–Zn ores and host rocks suggest a formation in an active oceanic core complex along the Jurassic slow-spreading ridge of the Piedmont–Ligurian Ocean.

In the Zgounder Ag-Hg high-grade deposit, Ediacaran magmatic rocks of different types and compositions have been intruded by several dolerite and rhyolite dike swarms. This contribution focuses on the 610–541 Ma period of the Zgounder mine region, starting with the volcano-sedimentary successions of the Bou-Salda Group (610–580 Ma), represented in the studied area by the Tadmant rhyolite. The overlaying Ouarzazate Group (580–541 Ma) consists predominantly of volcano-sedimentary series intruded by contemporaneous multi-pulses of felsic plutons. Geochemically, two magmatic associations are distinguished: (i) mafic metaluminous rocks of within plate and calc-alkaline to transitional affinity; and (ii) felsic-intermediate rocks of peraluminous and high-K calc-alkaline signature. For all of the samples, the hybrid isotopic signature (εNd(570) = − 0.9 to + 4.3) and the calculated TDM model ages from 1197 to 1526 Ma indicate mixing between a depleted mantle source with an enriched source (probably a Paleoproterozoic crust). These findings suggest that the Ediacaran magmatism of Zgounder deposit was emplaced in a long-lived syn-to-post-collisional environment during the metacratonic evolution of the northern edge of the West African Craton (WAC). During this period, huge volumes of mostly felsic magmas, typical of a Silicic Large Igneous Province (SLIP), were emplaced during multiple pulses. The last two pulses, at the final stage of the Pan-African orogeny (560–550 Ma), seem to be responsible for a pervasive hydrothermal activity recorded over the whole Anti-Atlas. Consequently, this hydrothermal activity led to the formation of numerous world-class precious and base metal porphyry-epithermal deposits, including the investigated Ag-Hg Zgounder deposit.

The state of the clay reserves of the exploited or potentially exploitable sites is diagnosed, integrating the geological, physico-chemical and mechanical aspects in order to better valorize these resources. This study focused on 15 representative samples collected in different geological contexts. The particle size distribution, Atterberg limits, X-ray diffraction (XRD), X-ray fluorescence (XRF), total organic content and calcimetry were determined. The mechanical characteristics were revealed by studying the shrinkage after drying/firing process, loss on ignition (LOI), the bending test and water absorption capacity (WAC). The studied clays presented a silty to sandy-silty composition with a clay fraction not exceeding 12.5% and a plasticity index (PI) between 20 and 30%. The carbonate and organic matter contents are low (CaCO3T < 12.5%, OM < 2.5%). The bulk mineralogy is dominated by quartz (5–36%), K-feldspar (3.3–19.7%) and goethite (8.8–25%). The clay mineral content is between 12 and 25.2%. It is dominated by illite (5–90%), kaolinite (0–70%) and chlorite (0–45%). Smectite, vermiculite and mixed-layer clays are rarely identified. The chemical composition is dominated by SiO2 (44.9–62.2%) and Al2O3 (10.5–19.6%). Technological and mechanical tests show a high bending strength (BS) (5.01–13.02 N/mm2) which is positively correlated with the quartz content but inversely proportional to the calcium carbonate content. The LOI (8.69–29.78%) and the WAC (7.88–35.72%) are tolerable. The drying shrinkage (DS) (0.31–14.43%) and firing shrinkage (FS) (0.24–5.59%) coefficients are low. The suitability of clays from the Beni Mellal-Khenifra region to be used in ceramic manufacturing is constrained by pretreatments (crushing, grinding, sieving) and formulation to balance the composition and/or the particle size curve or to correct the plasticity.

Besides being a cause of environmental problems, tailings and waste rock can also be potential sources of valuable minerals and metals. The Jerada mine (JM) in the eastern region of Morocco operated by Moroccan Coal Mines (MCD) for coal extraction is one of the many overburden mines in Morocco with large amounts of overburden since 2000 without rehabilitation plans. The main objective of this study is the coupling between 3D model as a tool to estimate the ore resources and evaluate the economic potential of coal mine waste rock (CMWR) piles and metallurgical study in the valorization of abandoned rejects. The study will initially focus on the 3D modeling of the CMWR piles and the estimation of their resources based on drill sampling to highlight the vast quantities of CMWR piles deposited on site. Physical–chemical characterization was performed using XRF, XRD, SEM, total C-S measurement and QEMSCAN. Eight CMWR piles (T01, T02, T03, T04, T05, T06, T07 and T08) were the target of our work to uncover the huge tonnages of coal stored in these stockpiles. The 3D model blocks show a total volume of 8.64 Mm3 of waste, which corresponds to 15.3 Mt on the piles. Chemical analyses have highlighted the presence of significant concentrations of carbon, T08 with nearly 50% of the tonnage 7.36 Mt and a %C that is close to 8.5 wt%; T01 and T02 with 5.31 Mt and a %C of 12.75 wt% and T03, T04, T05, T06 and T07 regrouping 1.84 Mt. It should be noted that the %S in the T08 approaches 2 wt% with a high degree of oxidation, which may represent a source of acid mine drainage (AMD). The high carbon content and the large tonnages obtained indicate that the waste can be reused by re-exploitation or reused in other fields to limit and reduce its environmental impact.

The flotation behavior of mixed copper ore during selective copper flotation was investigated using a geometallurgical approach. To this end, samples were taken from a production block at the Ouansimi copper deposit and subjected to laboratory batch kinetics tests and quantitative mineral analyses. Using a range of ore samples from different location in the same deposit, the influence of mineralogy on flotation performance was studied. The automated quantitative mineralogy technique was utilized to characterize the samples, revealing that bornite, chalcopyrite, and chalcocite are the copper-bearing sulfide minerals, whereas malachite is the major copper-bearing carbonate mineral. In order to construct a robust model with the highest quality data (Q2) and excellent goodness of fit (R2), the deposit was divided into two homogeneous geometallurgical domains using a K-means clustering algorithm based on mineralogical and metallurgical information. Copper recovery of samples by geometallurgical domain was correlated to the feed mineralogy through statistical algorithms for principal component analysis (PCA) and partial least squares regression (PLS) regression to look for relationships between mineralogical features and flotation recovery. For the domain 1, a significant negative correlation was found between copper recovery and the middling and locked copper association (iron oxide with a trace of copper, copper associated with gangue like biotite, barite, kaolinite, chalcocite locked and delafossite). By contrast, in domain 2, a negative effect on copper recovery was established due to the presence of iron oxide with a trace of copper and malachite and bornite.

Mining companies are increasingly turning to industry 4.0 to tackle economic challenges and to boost production efficiency. As one of the technological advances, sensor-based sorting systems (SBS) are increasingly used. It enables dry separation in early stage of raw material processing. The selection of appropriate sensing technologies is a vital aspect of implementing SBS systems, and there are not many research studies that treat the approach used to select the appropriate sensors; therefore, this paper demonstrates the selection of two combinations of sensors to pre-concentrate ore from a Moroccan copper deposit called Tizert. The approach used to select these combinations is based on analyzing the intersection between the detection principle of sensing technologies and preliminary geological and mineralogical characterization of the copper ore fragments. Results of this approach are two combinations of sensing techniques. The first is near-infrared spectroscopy combined with microwave treatment followed by infrared thermal imaging; this combination guarantees the detection of all copper-bearing minerals; the second combination is dual-energy X-ray transmission with X-ray fluorescence; it allows to detect valuable fragments and reduce surface-to-volume correlation errors as well as overcoming the resolution limitations of the XRT sensors. The strategy followed gives as result two combinations of sensors that allow researchers to concentrate at first on potential technologies.

The mine A tailings storage was used successively for the deposition of sulfide tailings, and the co-deposition of sludge and slag. With the objective to evaluate the hydrochemical behavior of these materials, humidity cell tests were used. These cell tests internationally operated to simulate sulfide mineral oxidation and acid generation at controlled laboratory conditions. It consists of weekly wetting and drying cycles using deionized water flush of the studied material. At the end of each cycle, water flush was analyzed for several geochemical parameters in order to compare their oxidation rates, generation of alkalinity, and metal leaching potential (As, Cu, Fe, Pb, and Zn). Four cell tests were performed for 16 cycles (105 days) on the mine tailing and the sludge/slag materials. Indeed, this study enhances our understanding of the reactivity of the sulfur generated by the mine tailing and the high concentrations of sludge/slag material in Cu. These materials generate contaminated water and are therefore likely to affect the quality of the surrounding environment.

The Mekong River Rapids outcrop in Loei Province appeared in the middle part of the Mekong River, a site of national geoheritage at the boundary between Thailand and Laos PDR. These rapids are not systematically classified on the geological map, and no studies have researched the rocks around the rapids in detail. This work aims to study petrography and the rocks’ chemical composition to explain the origin and to specify the names by field observation, petrography, and geochemistry. According to petrographical analysis, the studied rocks are classified into four groups: (1) a microcrystalline volcanic rock (alkaline rhyolite and rhyolite), (2) a garnet-pyroxene skarn, (3) a biotite-hornblende monzogranite, and (4) a dolomitic limestone. Major elements classify the studied rocks as rhyolite and dacite, while trace elements group them into rhyodacite and andesite fields. Geochemical data indicate that volcanic rocks generated from calc-alkaline magma erupted at the volcanic arcs related to subduction activities. Therefore, this work can hypothesize the geological model as granitic rocks intruded into carbonate hosts and metamorphosed into the skarn zone due to contact metamorphism. Meanwhile, the chill margin of the granite pluton rapidly formed as fine-grained igneous rocks with a volcanic eruption, which appeared at the Mekong Rapids.

Quartz veins with widths ranging from meters to hundreds of meters and lengths from tens of meters to kilometers, known as Giant Quartz Veins (GQVs), are ubiquitous in orogenic belts worldwide. These veins are very useful to gain understanding of fluid flow, quartz precipitation, and deformation mechanisms and also to unravel the geochemical history of their host rocks. The present work is dealing with multi-scale analysis (from orogen-to microscopic-scales) of the mylonitized GQVs encountered in the Cap de Creus and Canigó Massifs, Eastern Pyrenees, SW Europe. Despite being hosted in variable rocks and emplaced along different structures, the studied GQVs share various similar features: (1) the development of silicification halos, (2) evidence of different mechanisms of quartz growth through host rock replacement, host rock dissolution related to the opening of cm-wide vein networks, and aggregation of multiple crack-seal veins, and (3) a strong structural control on their emplacement. The GQVs postdate the development of regional cleavages but are affected by a mylonitic/phyllonitic foliation, showing evidence of deformation by dislocation creep and a wide range of microscopic shear sense indicators. The pre-existing structures along which the Roses GQV was formed vary even within hundreds of meters, from a brittle thrust fault to a mylonitic band. In the Esquerdes de Rojà GQV, an incipient to well-developed low temperature mylonitic fabric is present along more than 15 km, and grain-size reduction is mainly achieved along cataclastic bands. These features can be representative of the more than 700 GQVs that have been mapped in the Pyrenees.

Along NW Africa, scarce relics of the Alpine Tethys crust are associated with the Maghrebian Flyschs. In the Rif belt, a string of potential relics extends as tectonic slivers within the stacked external nappes from the Beni Malek serpentinite massif to the Bou Adel gabbro massif. These relics define the transported “Mesorif Suture Zone” (MSZ), whose interpretation is controversial. Here, we report on the large Bou Adel gabbro, based on detailed mapping and sampling. A thin, tectonic envelope of hydrothermally altered basalts followed upward by marbles and volcanoclastic carbonate meta-breccias is identified. The greenschist-facies metamorphism of the marbles is coeval with the imprint of a flat-lying foliation that affects both the clasts and matrix. Geochemical signature of the meta-basalts compare with that of the Central Atlantic Magmatic Province (CAMP) whereas the 190–196 Ma-old gabbro exhibits composition between E-MORB and OIB. Consistently, we hypothesize that the gabbro intruded a Late Triassic-Lower Liassic volcanic passive margin that evolved into a magma-poor transform margin. During the Lower-Middle Jurassic rifting climax, normal faulting and metamorphism would have affected the gabbro envelope subsequently overlain by extensional rafts from the proximal margin. The Ocean-Continent Transition (OCT) domain (Beni Malek) would have developed later further north. Non-inverted analogs could be found in the Limpopo and Namibia margins.

In salt-detached fold-and-thrust belts, salt can be accumulated along the front where can extrude locally. The nature and timing of salt accumulations were studied at the South-Central Pyrenees, along Les Avellanes diapir surroundings. Field data collected is used for mapping and the construction of a cross section covering the outer part of the fold-and-thrust belt, restituted until the base of the Eocene. The primary welding of the synclines during the Eocene obstructed lateral flow which created an underground accumulation. The collapse of the crest atop facilitated the extrusion of the diapir.

In this work, we present results of the application of paleomagnetism and the analysis of synsedimentary structures in order to clarify the age and origin of transversal anticlinal ridges in the northern border of the Central High Atlas (CHA). The results are interpreted in terms of paleogeometry of the main structures. The High Atlas fold-and-thrust belt is the result of intracontinental basin inversion during the Cenozoic convergence between the African and European plates. The studied ridges separate the three main synclines of the northern border of the CHA, namely Ait Attab, Ouaouizaght and Taguelft. Samples have been collected along the Tansrift ridge separating the Taguelft and Ouaouizaght synclines and to the west, Ouaouizaght syncline from the Ait Attab syncline. Paleomagnetic data reveal the presence of a magnetization component, stable in different lithologies in the ridges. This magnetization is carried by hematite, as evidenced by rock magnetism experiments on representative samples and by the results of thermal demagnetization of the studied samples, showing a maximum unblocking temperature around 680 °C. The paleomagnetic stable component observed in different specimens shows a systematic normal polarity. This component corresponds to the generalized widespread remagnetization known in the CHA, dated at 100 Ma. Directional analysis shows that this remagnetization is syntectonic (inter-folding), indicating that the studied anticlinal ridges were partially uplifted before 100 Ma, predating basin inversion during the Cenozoic convergence. Synsedimentary structures studied at the borders of these three synclines prove synsedimentary uplifting. These results allow to consider these three synclines as confined mini-basins separated by diapiric ridges at least since Bathonian time.

Aïr Precambrian basement (NE Niger) is unconformably overlain by deposits of the Tim Mersoi basin at West and of the Tenere basin at Southeast. The present work addresses the structural relationship between the basement and the overlying sedimentary cover. A methodological approach combining geophysic data (magnetic and seismic) interpretation and fieldwork was implemented. The field observation carried out along the major unconformity between the Tim Mersoi basin and Aïr basement revealed a fault and fracture system mostly oriented N135° to N180° (NNW-SSE) affecting similarly the sandstone formations called “Agadez sandstones” and its underlying basement formations. Structural interpretation of magnetic and seismic maps highlighted two regional lineament systems: the NNW-SSE seismic lineament affecting both the Aïr basement and Tenere basin in the East (Termit basin) and the magnetic one corresponds to the regional N-S In-Azaoua-Arlit fault system prolongated in the Tim Mersoi basin in the west. Interpretation of seismic section across the petroleum system of Termit basin showed that the same NNW-SSE fault system revealed by the fieldwork and seismic map affects similarly the sedimentary cover and the underlying basement. The combined analysis of obtained data reveals a continuum of brittle tectonic between Aïr basement and Tim Mersoi basin in the west and Tenere basin in the east. In the Tim Mersoi basin, this brittle tectonic would control the setup of the uranium mineralization in Arlit region, and in Tenere basin it constitutes a NNW-SSE petroleum system of Termit basin. This regional brittle deformation, deriving from the reactivation of sub-meridian Raghane shear zone (8° 30′) which was considered as a late to post Pan-African tectonic lineament.

The Barmer petroliferous basin in W Rajasthan (India) is ~ 50 km wide and ~ 200 km long trending NNW. The Barmer basin experienced a two-phase (NW–SE followed by NE–SW) extension during Early Cretaceous and Late Cretaceous-Paleocene times. It consists of fluvial to shallow marine sediments deposited between Jurassic to Miocene, with some distinct hiatus in between. Late Proterozoic Malani igneous suite/Malani rhyolite is the basement rock. The western margin rift shoulder consists of Malani basement isostatic flexural uplifts, while the eastern margin comprises thick sedimentary cover and is fault-bound. The objective is to understand the rift kinematics, structural inheritance and the type of deformation from field based studies. We carried out structural field studies along the rift margins that helped in deciphering the two-phase (NW–SE followed by NE–SW) extension through brittle shear tectonics. Cross-cutting relation among the NW and NE fault planes connotes the relative timing of the two extension phases. Other key observations from field studies are (1) presence of mega-scale transfer zones along the N margin of the basin, (2) NW trending rift faults inherited the pre-existing structures, (3) variation in strike and crosscutting nature of fault planes in eastern and western rift margins. Paleostress analysis further interprets the stress regime and relative timing of the tectonic events. Thus, the analysis helps in deciphering the rift evolution and the type of extensions related to tectonic inheritance.

Field data together with petrographic and geochemical analyses (δ13C, δ18O) of vein cements and host rocks are used to reconstruct the fluid flow evolution in a well-exposed carbonate thrust zone, the Montsec thrust sheet, Southern Pyrenees. The Montsec thrust places Upper Cretaceous marine limestones over Paleocene non-marine carbonates and clays. Within this thrust zone, four fracture sets including bed-parallel and bed-perpendicular fractures (F1 and F2, respectively), bed-parallel slip surfaces (F3) and strike slip faults (F4) have been identified. These fractures have been filled with four generations of calcite cements (Cc1-Cc4). Consequently, stable isotope analyses applied to these cements indicate three different geochemical trends: (i) similar δ13C values between all cements and their related host rocks (from 0 to + 2 ‰VPDB) that has been interpreted as buffering of the cement-forming fluids by the host carbonates; (ii) a progressive depletion in δ18O values from Cc1 to Cc3 (from − 7 to − 12 ‰VPDB) that is either attributed to a change in the fluid origin, a dilution of the fluid composition and/or an increase in the fluid temperature and (iii) an enrichment in the δ18O values from Cc3 to Cc4 (from − 12 to − 9 ‰VPDB), probably indicating the infiltration of a low-temperature, likely meteoric, fluid during thrust sheet exhumation and piggy-back transport of this thrust towards the south. The formation of successive fracture/vein sets as well as the geochemical variation of the vein cements through time indicates changes in the fluid origin, pathways and the extent of fluid-rock interaction during the emplacement of the Montsec thrust. Therefore, this study highlights how the evolution of carbonate veins could inform the fluid flow events during the geodynamic evolution of fold-and-thrust belt systems.

Gale Crater is one of the best-known sites on the Martian surface. It is located at 5.3°S, 222.3°W (137.7°E), and is ~ 155 km in diameter. It has become a target of particular interest because of the large mound of stratified material that occupies the crater entrance (~5000 m). Gale Crater is the landing site of the Mars Science Laboratory (MSL) rover Curiosity, which landed on the Martian surface on August 5, 2012 (NASA JPL, 2017). This work aims to provide a basemap that will serve as a reference map on which we can overlay data from other layers such as mineralogy and visualize geographic and geomorphological information. We used calibrated radiometric data from the Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) which is currently orbiting Mars and acquiring grey-scale images at a scale of 6 m/pixel over a 30-km-wide swath (Malin et al. in Journal of Geophysical Research: 112-E5, 2007), to generate a 6 m/pixel resolution mosaic of the entire crater, which will serve as the basemap for our studies of this site. The processing was done with ArcMap 10.6 and Qgis 3.28.0 software. The wide coverage and resolution of the CTX make it a good tool for geomorphological mapping of the surrounding units. The crater comprises sedimentary deposits, a bowl-shaped depression, and a central mountain (Blake et al. in Science 341-6153, 2013). The crater rim is quite degraded but still clearly identifiable, and the surrounding terrain has a bumpy, mantled appearance (Le Deit et al. in Journal of Geophysical Research 118–12, 2013), visible on the CTX mosaic. The generated basemap provides the geomorphic context for the various investigations we are conducting to study the Martian surface, in particular Gale Crater.

The term fossil fuel refers to oil, gas, coal, and oil shale. Recently, more and more often, they consider hydrogen as a fossil. In southern Australia, they even began to issue licenses for the search and exploration of hydrogen accumulations. Currently, the main hypothesis of the origin of fossil fuels is the organic theory, which implies the origin of fossil hydrocarbon fuels as a product of catagenesis (late stage of diagenesis) of organic sediments. However, to date, a huge amount of accumulated evidence indicates the significant possibility inorganic origin of fossil fuels. On the one hand, a concept develop the idea based on the generation of hydrocarbons occurs in the deep layers of the Earth due to inorganic synthesis. On the other hand, more than 40 years ago, a discovery of previously unknown phenomenon of transformation of the organic matter of sedimentary rocks under the influence of tectonic and seismic processes of the earth's crust because of mechanochemical reactions arising under the action of variable mechanical stresses was experimentally established and registered. The theory of different cycles of the carbon cycle on Earth developed in the last two decades, in combination with the above, leads to the conclusion that the planet's hydrocarbon resources are renewable under certain conditions and allow us to consider hydrogen as a fossil fuel.

The Sa’adi Formation (Santonian-Campanian) is one of the important reservoirs hydrocarbon-bearing zones in the southern Iraq. According to the reservoir quality, the Sa’adi reservoir is considered a clean tight reservoir (moderate to low permeability less than 20 mD) in all study area. The Sa’adi Formation subdivided into two members; the upper member is chalky limestone rocks and the lower member is limestone, the lower member can be further divided clearly into three units (A, B, and C) according to wells logs. Petrophysical properties showed a relationship with facies distribution, the relationship between porosity and permeability in some study wells through Winland R35 method, four types of pore throat sizes have been identified (nanopores, micropores, mesopores, and macropores). Upper Sa’adi and lower Sa’adi Unit C have the low quality related to medium average values of porosity less than 12% and permeability less than 2mD while it’s absence of oil saturation. The micropores and nanopores dominate of this flow and related to mud-supported microfacies of outer ramp and mid-ramp facies associations. While lower Sa’adi Unit A and B, mesopores and macropores marked with grain-support facies related to inner-ramp facies associations, which reflect to high porosity is 17% and medium permeability less than 20 mD with high oil saturation at (78–65%), it represents the best flow unit of Sa’adi Formation in West Qurna I and West Qurna II Oilfields.

This work aims to analyze and interpret a geophysical airborne dataset and to correlate them to field geological data in the order to study structures and subsurface bodies in the eastern part of the Paleozoic central massif of Morocco. This area is one of the most extended outcrops as inliers of Paleozoic basement affected by Variscan compressional events, covered by meso-cenozoic subtabular cover. Megastructures are organized as succession of anticlinoria and synclinoria with a NE-SW main trend. This area is characterized by important diversity of magmatic rocks and plutonic bodies and tectonic structures. Results of airborne data, aeromagnetic and spectrometric of Th element, show a very clear consistency of anomalies with superficial structures. They allow also to marking out and detailed mapping (i) ment granitic body and its surrounding metamorphic aureole rocks, (ii) basaltic flow of plio-quaternary age, and (iii) the main Variscan strike-slip faults as well as NE-SW to ENE-WSW structures corresponding to the main trend of Variscan structures of this range and their probable alpine bending in the central area against the granitic body. Filters and analysis applied on magnetic data such as, reduction to pole, vertical derivative, Euler deconvolution and upward continuations processing PVH, allow to enhancing anomalies and also to carrying out others deeper anomalies south-westward of Ment granitic bodies which can correspond to deeper plutonic bodies.

As a result of the studies within the study area, four areas of stable subsidence (hollows) were identified for the entire period of formation of the plate cover: Karkinitskaya, Indolo-Kubanskaya, East Kubanskaya, and Terek-Caspian. Each of the basins is characterized by a unique evolution, which manifests itself in differences in the tectonic regime and the rate of sedimentation. This determined the features of the geological structure of the basins, the sources of generation in them and the critical moment characterizing the process of generation–migration–accumulation of hydrocarbons in the system. In the centers of generation of hydrocarbons, the critical moment happened, when more than 50% of hydrocarbons emigrated from the source rock and accumulated in traps. As a rule, the springs are confined to the most submerged parts of the sedimentary basin, in which the deposits are in more severe thermobaric conditions. Based on the levels of modern maturity and transformation of OM of the identified and proposed oil and gas source rocks, as well as the obtained estimates of the specific densities of hydrocarbon emigration at 5 stratigraphic levels, independent generation centers were identified. The combination of steady subsidence of generation sources and uplift of adjacent areas of the Scythian Plate in the Neogene-Quaternary provided the conditions for long-range migration of hydrocarbons. This significantly expanded the area of probable accumulation and the area of the territory promising for the search for hydrocarbons.

The article is devoted to the study of the processes of migration and accumulation of hydrocarbons in the Meso-Cenozoic complex of the Black Sea-Caspian region. The simulation results made it possible to study and model the processes of migration and accumulation of hydrocarbons in the hydrocarbon systems of the Meso-Cenozoic complex of the Black Sea-Caspian region. All modeled hydrocarbon systems are characterized by migration from the main reservoir, which lies directly above the modeled oil and gas source formations, to the overlying ones. This is due to the peculiarities of the formation of sedimentary formations under conditions of alternating regressions and transgressions. The factor stimulating migration is the active tectonic regime of the studied sedimentary basins. Based on the modeling results, the conclusion about the wide development of hydrocarbon filtration processes is consistent with the presence of multilayer deposits. It has been established that the areas of subsidence are characterized by extended catagenetic zoning, which is due to the high rates of sedimentation and subsidence and, accordingly, the large thickness of oil source deposits in the area of oil formation. As a result of the research, four areas of stable subsidence (hollows) were identified for the entire period of formation of the plate cover: Karkinitskaya, Indolo-Kubanskaya, East Kubanskaya, and Terek-Caspian. All modeled generation-accumulation hydrocarbon systems are characterized by flows (to a greater or lesser extent) from the main reservoir, which lies directly above the modeled source reservoirs, to the overlying ones. A joint analysis of the actual oil and gas potential and hydrocarbon accumulations predicted by the modeling results within the study area showed that the vast majority of discovered deposits and manifestations are genetically related to generation centers located within the identified sedimentary basins.

The article presents the results of reconstruction and analysis of geodynamic conditions for the formation of the main structural elements in the Black Sea-Caspian region. The paper considers the basement and the sedimentary cover, united by the same type of reaction from an external or internal source of tectonic energy. The results of the research indicate that the predominantly offshore deep water Black Sea and South Caspian provinces are controlled by tectonic mega depressions that formed in the Alpine and recent epochs of tectogenesis. At the same time, both provinces include in their internal structure both elements that arose at different stages of Alpine and recent structure formation, as well as fragments of older plate and folded structures, reworked in these epochs and buried under Cenozoic or Cretaceous-Cenozoic deposits to varying degrees. The latter, in turn, partially or completely controls the position and configuration of the oil and gas regions within these provinces. We supplemented the data on the phase composition of hydrocarbon deposits with the results of the analysis of the location of deposits in relation to structural-geodynamic and basin systems of different ages. This allowed us to present a predictive scheme of zones of possible predominance of various types of fluids in the composition of potential accumulations and manifestations of hydrocarbons in the territories and offshore area of the region.

As part of the assessment of the oil and gas content of the study area, numerical modeling of hydrocarbon generation and accumulation systems was performed, as a result of which hydrocarbon generation centers located within sedimentary basins were identified. Based on the levels of modern maturity and transformation of organic matter of established and proposed oil and gas source rocks, as well as the obtained estimates of the specific densities of hydrocarbon emigration at different stratigraphic levels, independent generation centers were identified: Middle Jurassic, Lower Cretaceous, Eocene, Maikop, and Miocene. Fluctuations in the sinking rate of basins at different stages of their development had a decisive influence on the realization of their generation potential by oil and gas source strata. As a result, the coeval oil and gas source strata of the basins at different times overcame the critical moment and by now have realized their potential to varying degrees. In basins with low subsidence rates, there is a delay in the emigration process in relation to generation, which is not typical for basins with high rates. The main promising complex within the study area is Cretaceous deposits, the hydrocarbon saturation of which is provided both by their own oil and gas source strata and by outcrops from deeper horizons of the sedimentary cover. The second most important is the Paleogene complex. Periodic tectonic activity within the study area, starting from the end of the Paleogene, created conditions for vertical hydrocarbon flows and the formation of multilayer deposits.

The emission of volcanic gases can occur during both eruptive and quiescent stages of volcanic activity, affecting air quality in the surrounding areas and threatening human health when the concentrations exceed species-specific thresholds. In this regard, quantitative studies of model validation are essential before applying a simulator for probabilistic volcanic hazard assessment. Here, we provide a model validation aimed at testing the accuracy in providing realistic values of CO2 concentration at two active volcanic sites affected by persistent passive gas dispersion: La Solfatara (a maar crater within Campi Flegrei caldera, Italy) and Caldeiras da Ribeira Grande located in the north flank of Fogo volcano (São Miguel Island, Azores). We used published and original CO2 flux data as input for numerical simulations run through VIGIL, an open-source workflow for parallel simulations and probabilistic output using two Eulerian models, which account for the passive and gravity-driven gas transport, respectively. At Solfatara, we compared a 1-month-long simulation during June 2020 with CO2 concentration acquired by the INGV measurement station at 4 m from the ground in a selected point close to Pisciarelli vent: Our results showed a good correlation between the daily simulated and observed averages of CO2 concentrations. At Caldeiras da Ribeira Grande, we quantified the CO2 concentration at 43 tracking points, each referring to a specific acquisition (in space and time) during 13 selected days in July 2021. The comparison between the 1-month-long simulation and the observed data provided acceptable accordance. In both cases, we noted that the daily averaged concentrations provided by the model do not exceed the gas hazardous threshold limits. However, for shorter timescales (hours), a higher data acquisition rate is needed for future investigation.

The 79 AD Vesuvius eruption was characterized by two main phases: a sustained column Plinian phase, which deposited a thick white to grey pumice lapilli fallout deposit, followed by a column collapse phase, which emplaced several pyroclastic density current deposits. These latter are interstratified with five, minor, thin and lithic-rich fallout layers. The internal structure of the Plinian fallout deposit is weakly stratified, as observed at several studied locations from the Vesuvius slopes up to 20 km from the vent. Here we present chemical analyses for pumice lapilli samples collected at three type-locations representatives of the proximal, medial and distal facies of the deposits. The investigated samples display well-defined variations with respect to the stratigraphic height, both within the entire fallout sequence and within the individual layers recognized. The more evolved phonolitic white pumice clasts show a clear vertical gradient in all major and trace elements with, e.g. MgO, TiO2 and Sr linearly increasing from 0.21 to 0.73 wt.%, 0.22 to 0.35 wt.% and 389 to 605 ppm, while Al2O3, Zr and Nb decrease from 21.8 to 20.6 wt.%, 350 to 312 ppm and 70 to 60 ppm, respectively. The tephriphonolitic grey pumice clasts have a less evolved composition (e.g. MgO 1.65–1.85 wt.%, TiO2 0.56–0.59 wt.%, Al2O3 19.1–19.2 wt.%, Zr 270–297 ppm, Sr 845–915 ppm and Nb 49–50 ppm) and do not display appreciable vertical geochemical trends. These variations indicate a decrease in the degree of magma evolution as eruption proceeded, likely related to the emptying of a stratified, compositionally zoned magma chamber, in line with previous literature. Interestingly, these vertical trends extend to the tephriphonolitic grey pumice clasts from the overlying post-Plinian lithic-rich fallout layers (e.g. MgO increasing from 1.93 to 3.03 wt.%, Nb decreasing from 51 to 45 ppm), analyzed here for the first time. This possibly supports the idea that also the lowermost portions of the magma chamber were compositionally stratified.

Large explosive eruptions often generate compositionally zoned ignimbrites that provide evidence for the vertical stratification in the magma chamber and insights on magma withdrawal dynamics. In this regard, an excellent case is represented by the AD 79 eruption of Vesuvius, which consisted of two main phases. A first Plinian phase emplaced widespread fallout deposits and minor pyroclastic density currents (PDCs), characterized by a marked compositional variation from white phonolitic pumice clasts at the base, to grey tephriphonolitic pumice clasts at the top. This is commonly interpreted to reflect the emptying of a stratified magma chamber. A post-Plinian phase, emplacing mainly PDC deposits, followed, tapping the lowermost, tephriphonolitic “grey magma” still residing in the magma reservoir. Occasional occurrence of white juvenile clasts in the upper part of the sequence is also reported. We present here new geochemical data on the juvenile clasts from the 79 AD post-Plinian PDC deposits, collected at three type-locations representatives of the proximal and medial facies of the deposits in three different sectors around the volcano. Our dataset testifies the systematic coexistence of both grey and white pumice types at various stratigraphic levels. The grey pumice clasts depict quite regular vertical variations for both major and trace elements, with Fe2O3tot and TiO2 linearly increasing from 4.55 to 5.22 wt.% and from 0.51 to 0.65 wt.%, respectively, while Al2O3 and Zr regularly decrease from 19.2 to 16.9 wt.% and 294 to 255 ppm, respectively. The phonolitic white pumice clasts are much less common and do not display any regular vertical geochemical trend. Two possible interpretations can be proposed for such coexistence: 1) batches of the phonolitic “white magma” had remained trapped in the magma chamber and were sporadically discharged during the eruption of the “grey magma”; 2) the white pumice clasts represent accidental cognate lithic clasts that were scraped off from the basal Plinian fallout deposits by the highly erosive post-Plinian PDCs.

Somma-Vesuvius, Campi Flegrei, and Ischia are three active volcanoes in the Neapolitan Area (Italy). In this work, we evaluated the combined tephra fallout hazard posed by the three volcanoes on a large-size (~600 km × 700 km) and high-resolution (~3 km) domain. In order to explore the effect of the intrinsic variability in eruption and wind conditions on tephra hazard we used a probabilistic approach (probabilistic volcanic hazard assessment, PVHA). For Somma-Vesuvius and Campi Flegrei, we grouped the possible eruptive size classes into small-, medium- and large-scale eruptions, while for Ischia we considered only the large-scale scenario, as it is the only one that can affect the mainland. We created a synthetic dataset of ground loads by performing 1500 tephra dispersion simulations for each eruption size class of each volcano (for a total of 10,500 simulations) using the numerical model Fall3D. For each simulation, we randomly sampled the eruptive parameters from suitable probability density functions and meteorological conditions from the ERA5 reanalysis dataset on the period 1990–2020. The hazard evaluation has been performed using a Bayesian Event Tree (BET) approach accounting for the results of the simulations, the variability in vent location and the mean annual rates of eruption for each volcano and eruption size class. In this way we obtained a set of hazard maps for Southern Italy showing the threshold tephra load that would be exceeded with selected mean annual rates within a 50-year exposure time. We found that greater tephra load thresholds are exceeded in the south–south-eastern regions.

Permian–Triassic rifts of the West Siberian basin compose one of the largest continental rift systems in the world. They are nearly coeval to the Siberian Traps Large Igneous Province and mark the final stage of the amalgamation of the Northern Eurasia. Presence of acidic volcanic rocks along the mafic lavas is a specific feature of the West Siberian region. However, at this moment, felsic volcanics of this area are poorly studied. Here we present the first representative data on petrography, geochemistry, and U–Pb ages for silicic volcanic rocks from the drill cores of the deep boreholes in the Frolov-Krasnoleninsky region (the central part of the West Siberian basin). The largest rift structure of this area is Rogozhnikov-Nazym graben, composed of rhyolite-dacitic lavas. Lavas constitute the major part of the volcanic pile, while tuffs are subordinate (up to 15%). According to the seismic and well-logging data, the thickness of felsic volcanic rocks exceeds 0.7 km. Whole-rock chemistry of the silicic volcanic rocks of the Rogozhnikov-Nazym graben and other smaller rifts is very similar and corresponds to post-collisional extensional tectonic setting. Zircons from rhyolites and dacites yielded U–Pb (SHRIMP-II) ages ranging from 254 ± 2 to 248.2 ± 1.3 Ma (Late Permian–Early Triassic). Thus, volcanic activity in the Frolov-Krasnoleninsky region was nearly coeval to the main phase of the Siberian Traps emplacement in the Siberian platform.

The Buah Formation has been recognized as an active exploration target due to the potential for exposed carbonate rocks, which can be used as a proxy for hidden subsurface reservoir rocks. Petrographical observations and geochemical investigations of carbonate rocks provide useful insight into the diagenetic alterations and their effects on reservoir quality. The distribution of carbonate sediments is controlled by a variety of environmental parameters, including temperature, substrate, salinity, and the presence of siliciclastic materials. Metastable minerals, such as aragonite and high-Mg calcite (HMC) tend to transition to low-Mg calcite (LMC) and dolomite. To study diagenetic alterations, geochemical data of carbonate rocks from outcrops of Wadi Bani Awf (WBA) and Wadi Bani Kharus (WBK) in Jabal Al Akhdar, Oman, have been obtained using the ICP-OES technique. The Mg/Ca and Sr/Ca ratios of studied samples are plotted to show the relationship between hypothetical carbonate endmembers and Buah carbonates along with literature data. The samples from WBA and WBK outcrops exhibit three distinct groups that are anticorrelated, i.e., a decrease in Sr/Ca with an increase in Mg/Ca. The trend is consistent with the fact that the rhombohedral calcite can accommodate smaller cations (e.g., ionic radius of Mg2+ = 86 pm), whereas orthorhombic aragonite prefers larger cations (e.g., ionic radius of Sr2+ = 132 pm). Furthermore, the data are compared with samples collected in the Gulf of Mexico (e.g., 4193 and DIS2 from AC601 and GC53 sites, respectively). Some of the WBA samples match the data of sample 4193 precipitated from seepage of hydrocarbon-rich brine fluids with abundant micropores and shell material. While a few of the WBK samples have data that matches with micrite D1S2 sample precipitated from hydrocarbon-free brine fluids. The effect of diagenesis by incorporating Mg into the calcite mineral structure is represented by the third group, having samples from both WBA and WBK with the lowest Sr/Ca and highest Mg/Ca ratios. Our findings suggest that the anticorrelation of Mg/Ca and Sr/Ca ratios between three distinct groups of Buah carbonates may have been caused by varied diagenetic conditions ranging from micritization to mechanical and chemical compaction leading to dolomitization.

Volcanic gas emission represents a source of hazard to humans and the environment. They occur both during volcanic unrest, eruptions and in quiescent stages of the volcanic activity. Therefore, it is a widespread and frequent threat. Many gas species (e.g. CO2, SO2) can affect human health and even threaten life at concentrations and doses above species-specific thresholds. Depending on the relative buoyancy at the emission location, volcanic gas emissions can be generally classified as dilute passive degassing and dense gas flow. Numerical simulations of gas dispersion involve a workflow that can be complex and time-consuming, since it starts with the modelling of the wind field, proceeds with the gas dispersion simulation and ends with the postprocessing stage. This process should be repeated several times (hundreds to thousands) for probabilistic volcanic hazard applications, in which the uncertainty of the relevant input parameters (e.g. wind field, emission rates and source locations) is explored to obtain probabilistic outputs. Here we present VIGIL, a Python simulation tool that manages the gas dispersion simulation workflow and is interfaced with two dispersion models: a dilute (DISGAS) and a dense gas (TWODEE-2) dispersion model. We show results from different applications showcasing the various capabilities of VIGIL.

Petroleum production is constantly coupled to the production of large quantities of water, called formation waters, which are originally associated to hydrocarbons from a given oil reservoir. In this work, we propose to chemically characterize and environmentally assess the waters produced from boreholes in the regions of Jeffara and the Ghadames basin in southern Tunisia. For that, water samples from the TAGI reservoir, Triassic in age, the Acacus reservoir, Upper Silurian in age, and the Bir Ben Tartar reservoir, Ordovician in age, which are major siliciclastic reservoirs producing oil in southern Tunisia, were the subject of a thorough sampling. A total of twenty-eight borehole water samples were collected from the wellheads (17 from the TAGI reservoir, 7 from the Acacus reservoir and 4 from Bir Ben Tartar reservoir) and two samples were recovered from the Waha treatment centre. All samples were analyzed in the Petroleum Research and Development Centre (CRDP) ETAP using the ICP-AES method. The geochemical results and the chemical facies evaluation show a tight similarity between all waters recovered from different reservoirs with a predominance of the chloride-sodium facies. This is despite that the three reservoirs are not connected. This resemblance is probably due to the common marine origin of these formation waters. Nevertheless, waters recovered from the Acacus reservoir are characterized by a strong acidity and a very high salinity, which can reach 290 g/l. Produced waters are treated and discharged of traces of hydrocarbons (gas and liquid) and their solid loads in order to be reinjected into injection wells and the excess is injected into discharge wells. The quality of this water does not comply with the standards for discharge into the water environment. No produced water is currently discharged at the surface. Should the case arise in the future, the NT106.03 standards must be strictly obeyed. Potentially, excess production water from oil drilling can be recovered and adequately treated for use in agricultural irrigation networks.

The distribution of CH4 and CO2 concentrations along marine sediment vertical profiles (up to 4 m depth below the sea floor) from different sectors of the Kara, Laptev and East-Siberian Seas (Russian Arctic Seas) is presented. The symbiotic correlation between their concentrations was shown. The correlation coefficient (R) varied from 0.58 to 0.97 for the sediments of the Kara Sea and it did not depend on the CH4 and CO2 distribution along the vertical sediment profile. The concentrations of CH4 and CO2 synchronously increase with depth in the Kara Sea and the highest concentrations of CH4 and CO2 are observed at 170–190 cm. It has been shown that sulfate reduction process, acetogenesis, methanogenesis and methanogenesis involving dimethyl sulfide leads to CH4 and CO2 parallel formation. The δ13C–CO2 value gradually decreases from − 17 to − 27‰ versus VPDB with the sediment depth. The evidence of CO2 deep origin is the δ13C high average value, varying from − 18 to − 10‰.

Wettability measurement of a crude oil–brine–rock (COBR) system is an integral part of the special core analysis (SCAL) since it influences the oil and water distribution and microscopic displacement of the former by the latter in a reservoir rock pore space. Wettability depends on several factors such as the type of rock, oil, and water properties, and the amount of time the pore space has been exposed to a given phase, i.e., oil, water, or both. Amott or its variant, the Amott-Harvey test, is perhaps the most time-honored and accepted method for wettability determination. Given the fundamental characteristics or definition of wettability, the Amott method is the most “logical” because wettability is determined based on the spontaneous and forced displacement of the oil by water and vice-versa. In a typical Amott test for a core sample, four different displacement cycles are required, which can be very time-consuming. We have recently designed a modified Amott method that is based only on the spontaneous displacement, which is carried out simultaneously on a pair of core samples originating from the same formation. Excellent, unambiguous wettability results have been obtained on the tested COBR system that proves the efficacy of our novel approach. Finally, the step-by-step methodology included in our paper demonstrates that it is not only practical and efficient, but also reliable, which can be easily implemented in the wettability determination of a given COBR system.

The current study reviews the techniques and methodologies used for analyzing and modeling a potentially disastrous event called a “kick.” Throughout the years, new and robust technologies have been developed to detect and mitigate such an event. Even so, there are still cases that the applied technologies fail and undetectable kick transform into catastrophic blowouts. This study aims to review the latest literature and provide a holistic approach to modeling and analyzing a kick, endeavoring to enhance the existing detection and mitigation techniques. PRISMA reporting system was employed to review the literature systematically. The review provided valuable information about the currently applied methodologies and the advances established throughout the years. Cubic equations of states and semi-empirical mathematical models were presented as the means to model the fluid flow and the thermodynamic state of the kick. Factors affecting the kick behavior, such as friction in annular space, fluid compressibility, heat transfer effects, the solubility of hydrocarbons, hydrogen sulfide, and carbon dioxide in drilling mud, changes in bottom hole pressure, and the gas bubble rise velocity, were also considered in the mathematical models. Afterward, the limitations of the reviewed models, such as the one-dimensional and single fluid flow patterns, the disregarded heat transfer effects, gas solubility, and temperature profiles, were investigated and discussed. Finally, considering the constraints and gaps in the literature review, the study recommends a reliable and accurate methodology to analyze and model a hydrocarbon kick. The suggested method combines the existing equations of states and semi-empirical correlations with the power of computational fluid dynamics. Eventually, it aims to produce models based on three dimensions, accounting for transient conditions, dynamic flow regimes, and critical factors affecting the behavior of a kick.

With the approval of the REPowerEU plan, the European Union intends to build partnerships to produce mutually beneficial gains by aiming to promote renewable energy and cooperate on green technologies and innovation. In addition to the increased supply of liquefied natural gas from the United States and Canada, it is necessary to intensify the southern gas transport corridor, formalize political agreements with gas suppliers such as Egypt and Israel to increase natural gas supplies, and boost the energy dialog with Algeria. Then, it is necessary to explore the export potential of sub-Saharan African countries. The shift to an economy less dependent on fossil energy offers significant opportunities beyond the issue of security and energy supply. Indeed, the new European decarbonization goals to rapidly advance the green transition pave the way for a new perspective in geostrategic cooperation in the Mediterranean. For the Mediterranean, geostrategic cooperation could combine economic development and renewable energy production. With this paper, we aim to estimate the energy potential of Mediterranean countries for renewable energy production to engage in more sustainable energy strategies, policies, and systems. We pay particular attention to infrastructural availability and plant capacity. We, therefore, intend to investigate possible synergies to combine energy and environmental policies in line with European climate policies.

The identification of family affiliation of samples emerging from oils and source rocks is a topic of primary importance in the field of exploration geoscience. We demonstrate how spectral clustering can be applied in the context of chemometrics on a set of rock extracts from Western Greece, using quantitative information of normal alkane (nC15–nC35) concentrations. The developed method is based on the creation of a graph Laplacian matrix that represents the latent graphical structure of the samples, and the subsequent estimation of the underlying clusters based on the eigenvectors of this matrix. The number of clusters is determined by optimizing the modularity of the resulting graph, thus ensuring high intra-cluster and low inter-cluster similarity. Our results highlight that the proposed approach partitions the geological samples into groups with distinct concentration profiles of n-alkanes and attains higher modularity values than methods traditionally employed in hydrocarbon exploration. This empirical study showcases the reliability of spectral methods to support source rock classification and provides a way to facilitate geochemical interpretations.

This study is intended to compare the capabilities of three different deep learning-based convolutional neural network models in predicting reservoir rock porosity and absolute permeability from 2D carbonate rock images. We consider a comprehensive evaluation scenario to investigate the performance and training time involved in using the proposed models. These are studied and evaluated using 2D micro-CT images captured at various image resolutions from the four different core samples. The selected core samples demonstrate a wider range of absolute permeability and different levels of heterogeneity. We achieve model variability by adopting the transfer learning framework in two of the three designed models using pre-trained, VGG16, and MobileNetV2 models. Results obtained demonstrate that transfer learning improves model accuracy to predictions at the expense of computational time. With the influence of transfer learning, results show that the accuracy and computational time largely depend on the number of trained parameters being transferred. The proposed models can predict both the rock porosity and absolute permeability within a few seconds compared to numerical simulations and experiments which require larger amounts of time.

The Late Carboniferous and Early Permian Al Khlata Formation represent the lower unit of the Haushi Group, related to the third glacial event in the Arabian Plate. Al Khlata Formation, which is deposited in proglacial fluvial and deltaic systems, is an important hydrocarbon target in Oman. The accurate estimation of the amount of hydrocarbon that can be produced from Al Khlata reservoirs is very challenging because the rock properties between wells in the Block 56 vary significantly, and the distribution of the petrophysical properties is poorly understood. This study aims to construct a petrophysical model and predict the vertical and lateral distribution of the petrophysical properties of the Al Khlata sandstones in Block 56 within depositional facies and sequence stratigraphy. This study is based petrophysical analysis using wireline logs and drilling cuttings. However, the study revealed that the Al Khlata Formation consists of two sandstone bodies: sand 2 and sand 1, (from oldest to youngest), characterized by significant heterogeneity in lithology and petrophysical properties. The thickness of the correlatable sandstone bodies within the Al Khlata Formation varies from one well to another because their deposition was highly controlled by the salt movement during the Late Devonian to the Late Carboniferous hiatus. Moreover, this study has revealed that the correlation between wells allowed the prediction of the influence of the glacial environments on the petrophysical properties of sandstone bodies. There is no consistent trend for the lateral and vertical distribution of porosity and permeability of the lacustrine and deltaic proglacial sandstone bodies, due to the complexity of the glacial environment. The degree of comparison between the two oil-bearing sandstones in terms of petrophysical properties is obvious. For example, sand 2 has good to excellent reservoir quality because of low average shale volume, and good average porosity. Sand 1 is a tight reservoir because it is enriched with shale, has poor porosity, and is very hard to drill because of diamictite. Subsequently, all of that has a significant impact on the hydrocarbon potentiality of each sand. Such modeling will help in drawing more efficient drilling, production, and recovery strategies.

Mauddud Formation (Late Albian–Early Cenomanian) is one of Iraq’s most important carbonate hydrocarbon reservoirs. Fifty-four core samples and one hundred fifty thin sections were made from several wells of Mauddud Formation in Ratawi, south Rumaila, and west Qurna oilfields, southern Iraq. The mineralogy of this formation is limestone and dolomite. The microfacies analysis results in five main microfacies associated with Mauddud Formation, including mudstone, wackestone, packstone, grainstone, and dolostone. In addition to ten submicrofacies including planktonic mudstone, benthic wackestone, bioclastic wackestone, algal wackestone, peloidal wackestone, bioclastic packstone, benthic packstone, benthic grainstone, bioclastic grainstone, and peloidal grainstone. These facies are indicated to be shallow restricted, lagoon, shoal, open marine, and mid-ramp environments. It was deposited on a shallow carbonate platform with a ramp setting. Several digenetic processes are affected in this formation: micritization, neomorphism, dissolution, cementation, dolomitization, and compaction are the main diagenetic processes. Dolomitization and dissolution processes improved the porosity and permeability with higher reservoir quality while cementation reduced the reservoir quality.

For centuries, the landscape of Mediterranean mountains has been shaped by the construction of terraces often supported by dry-stone walls, to allow farming activities. Nowadays, traditional dry-stone wall terraces are often replaced or combined with mechanically constructed terraces. Compared to dry-stone terraces, these behave differently regarding water retention, soil erosion and slope stability. The aims of this study are (i) to characterize a mechanically terraced slope (0.1 km2) partially protected by dry-stone walls and (ii) to set up a high-resolution stability analysis to verify its capabilities in predicting instabilities. The study site is located in the Troodos Mountains (Cyprus). Field observations were made between October 2021 and April 2022. Measurements of depth, hydraulic conductivity and bulk density, as well as the collection of samples for texture analyses, were performed for the physical characterization of soils. The study site was visited after several storms to map areas affected by instabilities. Rainfall was measured by a local meteorological station. A photogrammetric survey was made with a GoPro9 camera mounted on an unmanned aerial vehicle developed by the Unmanned System Research Laboratory of The Cyprus Institute both in firmware and software. The collected data were used as input into FSLAM, an open-source model that couples a simplified hydrologic model with an infinite slope stability analysis. The soil was a loamy sand, with a depth ranging between 0.30 and 0.80 m, an average bulk density of 1.70 g/cm3 and a hydraulic conductivity of 2.05 × 10–3 m/s. From the UAV flights, a DEM with a horizontal resolution of 0.035 m was produced. However, for modelling purposes the DEM was resampled at 0.21 m, to reduce calculation times and avoid high depth-to-length ratios at the single cell (infinite slope assumption). Preliminary results from multiple runs showed that the model responds reasonably well to flow accumulation and variations in soil depth. The model predicts higher instabilities for wetter deep soils. However, at this resolution it was not able to identify specific locations of failure. To improve the model output, FSLAM could be integrated with a routine able to process variable soil depths (now constant within soil units) and to route surface runoff.