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Late Pleistocene and Holocene sedimentation records changes in glacio-eustatic cycles, oceanography, active tectonics, and sediment supply. Here, we use high-resolution seismic-reflection profiles in Te Tai-o-Aorere Tasman Bay to investigate sedimentary deposit distributions associated with sea-level cyclicity over ∼140 ka. We identify nine seismic stratigraphic units below the inner continental shelf, interpret their character based on stratal relationships and acoustic properties, and infer ages using global sea level. The sequence includes stacked deposits and unconformities associated with the shifting shoreline over glacial cycles. Prominent erosional features include a lowstand ravinement surface and two transgressive surfaces formed during sea-level rise following the last two glacial maxima of ∼20 ka and ∼140 ka. The youngest surface marks the base of post-glacial sediment accumulated since ∼12 ka in the study area. Post-glacial sediment includes five seismically mappable units, covering an area of ∼1400 km2 and deposit volume of ∼9 km3. Time-averaged sediment accumulation rates are estimated to range from a maximum of ∼1.6–2.8 m/kyr to ∼0.5–0.9 m/kyr. Sequence stratigraphy interpreted in Te Tai-o-Aorere Tasman Bay is representative of accumulation in a relatively wide-shelf, sheltered inner bay setting supplied by mountainous catchments, and provides stratigraphic context necessary for future stratigraphic and tectonics studies. [ABSTRACT FROM AUTHOR]

Abstract In numerous carbonate reservoirs in the Middle East, peloidal packstone‐grainstones are rock types with excellent pore storage potential in micritised microporous grains. However, the origin of the micro‐porosity and associated micro‐spar remains unclear, and one hypothesis is that both micro‐spar and porosity originate from early marine micritisation and were later altered during subsequent diagenesis (i.e. cementation recrystallisation). The south‐eastern coast of the Arabian Gulf is recognised as a modern, albeit miniature, depositional setting analogue to Mesozoic carbonate sequences that form the supergiant reservoirs of the Middle East. Using optical microscopy, backscattered scanning electron microscopy and carbon and oxygen stable isotope analysis the present study aims to document the nature of internal microstructures of micritic envelopes and peloids from the surface sediments of various sub‐environments of the Abu Dhabi Lagoon. Results highlight a high degree of diversity and heterogeneities of most micritic envelopes and peloids observed across the sub‐environments. First, carbonate grains from ooid and bioclastic shoals show the simpler micritic envelopes. Here, micritic envelopes and peloids show sparse microborings filled with banded radial aragonite cement, a pattern of production of cryptocrystalline texture (e.g. micritisation) that is similar to the sequence of micritisation observed in the modern sediment of the Great Bahama Bank. Conversely, in the subtidal and intertidal zones with mangroves or seagrass, the micritic envelopes and peloids are much more complex and show multiple generations of microborings that are either empty or filled with carbonate materials of varying types (i.e. various cements, fragments, etc.).

In numerous carbonate reservoirs in the Middle East, peloidal packstone‐grainstones are rock types with excellent pore storage potential in micritised microporous grains. However, the origin of the micro‐porosity and associated micro‐spar remains unclear, and one hypothesis is that both micro‐spar and porosity originate from early marine micritisation and were later altered during subsequent diagenesis (i.e. cementation recrystallisation). The south‐eastern coast of the Arabian Gulf is recognised as a modern, albeit miniature, depositional setting analogue to Mesozoic carbonate sequences that form the supergiant reservoirs of the Middle East. Using optical microscopy, backscattered scanning electron microscopy and carbon and oxygen stable isotope analysis the present study aims to document the nature of internal microstructures of micritic envelopes and peloids from the surface sediments of various sub‐environments of the Abu Dhabi Lagoon. Results highlight a high degree of diversity and heterogeneities of most micritic envelopes and peloids observed across the sub‐environments. First, carbonate grains from ooid and bioclastic shoals show the simpler micritic envelopes. Here, micritic envelopes and peloids show sparse microborings filled with banded radial aragonite cement, a pattern of production of cryptocrystalline texture (e.g. micritisation) that is similar to the sequence of micritisation observed in the modern sediment of the Great Bahama Bank. Conversely, in the subtidal and intertidal zones with mangroves or seagrass, the micritic envelopes and peloids are much more complex and show multiple generations of microborings that are either empty or filled with carbonate materials of varying types (i.e. various cements, fragments, etc.). [ABSTRACT FROM AUTHOR]

Copyright of Iraqi National Journal of Earth Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The buccinid gastropod Ancistrolepis carolineae Squires, 1984 is the earliest known and shallowestmarine species belonging to the extant genus Ancistrolepis Dall, 1895, which is endemic to the NorthPacific region. This species is of late early Eocene (Ypresian Stage) age and is about 7 million years older than the previously oldest known record (late Eocene) of the genus. This rare species occursat several localities in a 1-m thick bed (“Stewart bed”) of fossiliferous shallow-marine sandstone within the Llajas Formation, on the north side of Simi Valley, Ventura County, southern California.The “Stewart bed” contains a rich fauna of subtropical mollusks and other invertebrates, which lived just below effective wave base, at the distal edge of a braid delta, immediately adjacent to an upper bathyal prodelta/slope environment, where a rich microfauna of calcareous nannofossils and benthic foraminifers lived. Dispersal of A. carolineae would have been either via drifting of buoyant “pouches” containing its non-planktonic eggs or by rafting of its adults in buoyant plant material debris. The dispersal of A. carolineae northward coincided with the cooling of the NorthPacific waters during the late Eocene, thereby providing the opportunity for Ancistrolepis to adapt to living in bathyal waters and also to living in association, in some cases, with chemosynthetic (methane) cold seeps.

Holocene evolutionary history of the Banni Plain in the Great Rann of the Kachchh Basin is reconstructed from a subsurface sediment core of ca 50 m. Detailed data on textural and lithofacies variations, grain‐size analysis, environmental magnetism and accelerator mass spectrometry 14C dates on seven samples were generated on the sediment core retrieved from the Banni Plain near Berada. A high‐resolution record extending back to 10 ka has been reconstructed from the top ca 40 m of the core section comprising shallow marine sediments. The core is divisible into five depositional units. The basal part is a fluvial depositional unit followed upward by estuarine, sub‐tidal, intertidal and supra‐tidal environments. The sediment accumulation rate is highest in the sub‐tidal to intertidal facies (1.9 cm year−1) and decreases towards the supra‐tidal facies to 0.09 cm year−1. Environmental magnetic analysis, χlf coupled with the S‐ratio, indicates high magnetic mineral concentrations during the Early Holocene, suggesting a wet period accompanied by high monsoon precipitation. This is followed by the onset of semi‐arid conditions in the Great Rann of the Kachchh Basin as indicated by the low values of the χlf and S‐ratios. A westward and northward shift in the shoreline towards the deeper part of the basin is suggested during the Late Holocene, which is coupled with aridity and reduced monsoonal conditions. The change in depositional pattern from the retrogradational deposit of fluvial (Unit 1) to estuarine sediment (Unit 2), progressing to sub‐tidal (Unit 3), is attributed to sea‐level transgression followed by regressive intertidal (Unit 4) to supra‐tidal deposition (Unit 5), culminating in complete withdrawal of the sea, aided by tectonic uplift, during the Late Holocene. The results reveal that the sediment accumulation rates and depositional environments changed over time in response to changes in sea level from minima to maxima and then eventually to the present level. [ABSTRACT FROM AUTHOR]

Sedimentary pyrite trace-element composition is an established proxy for determining paleo-ocean geochemistry and atmospheric oxygen concentrations through deep time. However, its applicability over shorter time-scales (i.e. <20 Ma) is not well known. To test this, we targeted fine-grained pyrite in the Hovea Member of the Kockatea Shale (Perth Basin, Western Australia), which encompasses the late Permian inertinitic interval and the end-Permian to Early Triassic sapropel, and spans approximately 10 million years. The end-Permian mass extinction (EPME) was the largest extinction event in Earth history, and its greatest effect is documented in the marine environment. Samples were collected from two oil exploration wells—Redback-2 and Hovea-3—spaced ∼20 km apart. In the two boreholes, a change in depositional facies (i.e. between the inertinite and sapropel) occurs below the Permian–Triassic boundary and records the transition from a marginal marine to a shelf environment. This transition is highlighted by several lithogeochemical indicators (e.g. negative shift δ13C values and Corg reduction; increases in Ca, Fe and P), which are themselves tied to fundamental changes in modal mineralogy between the two zones. Importantly, the sapropel also records a major increase in iron sulfide burial over that in the inertinite. LA-ICPMS analyses of pyrite demonstrate that trace-element abundance is highest in samples below the facies transition, and in places reaches a few percent, particularly of Ni (4 wt%), Co (1.5 wt%) and As (2.8 wt%). Moreover, these and other trace elements decrease by an order of magnitude in concert with the negative shift in δ13C values in the sapropel zone. Various whole-rock based paleosalinity indicator ratios (e.g. B/Ga) indicate that the areas of the Perth Basin intersected by Redback-2 and Hovea-3 were not fully connected to the open ocean at the time of the EPME, which leads us to conclude that the very high trace-element values in the sedimentary sulfides are reflective of regional environmental shifts rather than a global signal. Nonetheless, a geochemical contribution from a distant igneous province, such as the Siberian Traps Large Igneous Province, cannot be ruled out. Our work underscores the strength of sedimentary pyrite as a robust paleoenvironmental proxy in the marine environment and highlights the need for further investigation of pyrite trace-element profiles across the mass extinction interval in other sedimentary sequences around the globe. LA-ICPMS-based geochemistry of sedimentary pyrite from the Hovea Member of the Kockatea Shale is considered within a lithochemostratigraphic context. The overall interpretation of the results involves a change in depositional setting from the marginal in the late Permian brackish waters to shelfal marine and loss of oxygen in the Early Triassic Perth Basin. [ABSTRACT FROM AUTHOR]

The Gordon Lake Formation (GLF) of the Paleoproterozoic Huronian Supergroup is a siliciclastic-dominated succession ranging from 300 to 1100 m in thickness. Lithostratigraphic and sedimentological analyses of the formation in the Bruce Mines and Flack Lake areas, and Killarney and Lady Evelyn-Smoothwater provincial parks, Ontario, Canada, revealed seven lithofacies, which comprise three distinct lithofacies associations. The lithofacies associations are subtidal nearshore, subtidal to shallow shelf, and mixed intertidal flat. A variety of structures interpreted to be biogenic in nature, including microbially induced sedimentary structures (MISSs) and stromatolites, are preserved, which support local microbial colonization in a tidally influenced marine environment. Wave, current, and tide-generated sedimentary structures, including symmetrical ripples, trough cross-beds, flaser and lenticular bedding, and mudstone drapes, are abundant in all study areas. Storm influence is suggested by normally graded deposits, mudstone rip-up clasts, and soft-sediment deformation structures (SSDSs), including load casts, ball-and-pillow structures, convolute bedding, and pseudonodules. Interbedding and interlamination of sandstone and mudstone units are present throughout the GLF and represent fluctuations in water level and energy, related to tidal and storm processes. A lowermost carbonate-rich unit may represent a period of low clastic influx. The contacts with the underlying Lorrain and overlying Bar River formations appear gradational. The depositional environment can be visualized as an open coast, shallow marine shelf that was influenced by microbial mats, tides, and storms. [ABSTRACT FROM AUTHOR]

Bala is located in Central Anatolia and is a sub-basin of the Tuzgölü basin, which consists of many basins formed in response to the closure of the Neotethys ocean. The evaporites in Bala sub-basin formed under the influence of regional uplifting during the Middle Eocene period with gradual shallowing in response to the structural compressional regime. The Bala sub-basin comprises four units from bottom to top: the Lower Unit (BU1) consisting of mudstone, claystone with limestone layers; the Evaporites (BU2) containing dominant gypsum with anhydrite; mixed siliciclastic-carbonate-evaporitic deposits (BU3); and the Upper Unit (BU4) containing conglomerate-sandstone-claystone and siltstones. The evaporitic unit, which are the main subject of study consists of primary selenitic gypsum, anhydrite, locally celestite crystals and secondary gypsum formed due to the anhydritization of primary gypsum and then hydration of these anhydrites. The results obtained from mineralogical-petrographic, geochemical and isotopic (δ18O and δ34S) investigations indicate that these evaporites were deposited in shallow marine to sabkha environments dominated by arid conditions. The presence of primary selenite crystals, the anhydrite with nodular, chicken-wire, and mosaic structures support precipitation occurred in a partially saline shallow water. The excessive thickness of the evaporitic accumulation, chaotic masses including gypsum breccia, salt diapirs and dome structures are attributed to tectonic processes acting during the formation of the Central Anatolian basins. [ABSTRACT FROM AUTHOR]

The Küplüce-Gökçesu Basin, located in northwestern Anatolia, is an Eocene-aged shallow marine basin known for its rich carbonaceous sediments. The basin is underlined by Paleozoic metamorphic rocks, granites from the Sakarya Massif, and Jurassic-Upper Cretaceous turbiditic and carbonate rocks. The sedimentary deposits in the basin consist of two main lithological units, namely, the Tokmaklar and Sazlar Formations. The Tokmaklar Formation comprises marl, bituminous marl, clayey bituminous limestone, Nummulite limestone, and marl-clay-sandstone successions. Economic coal formations are found at the base of the Tokmaklar Formation, along with bituminous limestone and marl. The Sazlar Formation is composed of thick layered sandy limestones and marls, deposited in reefal conditions. Previous studies conducted in the 1980 s estimated the coal reserves in the Küplüce-Gökçesu Basin to be around 40 million tons. However, this study reveals the discovery of a new coal seam that was not previously identified, with a potential thickness of approximately 11 m. This discovery suggests that the coal reserves in the region could be significantly larger than previously known, potentially 5-6 times greater. The quality of the Küplüce-Gökçesu coals is classified as semi-bituminous hard coal of the lower bituminous coal group, based on chemical analysis results. This study contributes to the understanding of the geology and coal potential of Eocene basins in Anatolia and provides valuable information for future exploration and exploitation activities.

Sedimentological and palynostratigraphical studies were performed on 189 ditch-cutting samples composited at 50 ft intervals from four well sections located in KW field, onshore western Niger Delta Basin, Nigeria, using sieving and visual microscopic observations, hydrochloric and hydrofluoric acids digestion methods to determine their lithological character and palynologic content of the sedimentary successions. The basis of these data is to interpret the lithofacies and biostratigraphy, establish the age of the strata, establish the palynological zones and infer the environments of deposition. Five lithofacies delineated based on the sedimentological study were very coarse sand, coarse to fine sand, shaly sand, muddy sand, and sandy to silty shale. The age of the sedimentary successions ranges from Early Miocene to Pliocene based on the bio-assemblages of these key species. The Early Miocene age is characterized by the occurrence of Magnastriatites howardi, Psilatricolporites triangularis, Praedapollis africanus, Pachydermites diederixi, Spirosyncoilpites spiralis, Praedapollis flexibility, Racemonocolpites hians, Verrutricolporites rotundiporus, Verrutricolporites microporus, and Psilatricolporites divisus. The Middle Miocene age is characterized by the FAD of Crassoretitriletes vanraadshooveni, the occurrence of Belskipollis elegans, in association with Striatricolporites catatumbus, Verrutricolporites rotundiporus, Verrutricolporites microporus, Crassoretitriletes vanraadshooveni, Racemonocolpites hians, Retibrevitricolpites obodoensis, and Retibrevitricolpites protrudens. The Late Miocene age is characterized by the occurrence of Multiareolites formosus, Cyperaceaepollis sp., Stereiosporites sp., Peregrinipollis nigericus, Gemmamonoporites sp. (Cleistopholis patens), Laevigatosporites sp., Verrutricolporites sp., Nymphaeapollis clarus, and Verrutricolporites usmensis. The Pliocene age is characterized by the basal occurrence of Retistephenocolpites gracilis in association with Nymphaeapollis clarus, Cyperaceaepollis sp., Laevigatosporites sp., Verrutricolporites sp., and Crassoretitriletes vanraadshooveni. The boundary between the Early Miocene and Middle Miocene from the studied oil well sections is marked by the first appearance datum (FAD) and numerical maximum occurrence of Striatricolporites catatumbus and Belskipollis elegans and FAD of Crassoretitrilettes vanraadshooveni. The boundary between the Middle and late Miocene is defined by the LAD of Verrutricolporites rotundiporus, the quantitative top and numerical maximum occurrence of Racemonocolpites hians, and the numerical maximum occurrence of Zonocostites ramonae. The boundary between the late Miocene and the Early Pliocene is marked by the first appearance datum (FAD) and the numerical maximum occurrence of Retistephenocolpites gracilis, the numerical maximum occurrence of Echiperiporites icacinoides, and the highest abundance of Monoporites annulatus. Four palynozones PAZ-1, PAZ-2, PAZ-3, and PAZ-4, and ten sub-zones were erected. Finally, Fluvial-coastal to shallow marine environments of deposition were inferred for the sedimentary successions using sedimentological study, nature of organic matter, and association of key environmentally-sensitive biomarker species.

Eight stratigraphic sections from well-exposed outcrops of the Early to Middle Miocene Tanjong Formation in the Kalabakan area, southeast Sabah, were investigated using an integrated approach, in which a comprehensive sedimentological facies analysis was linked with bulk geochemistry and palynological analyses. The integration of facies analysis, elemental CHNS, Fourier-transform infrared spectroscopy (FTIR), and palynological data provided a refined evaluation of the origin of organic matter (OM) and the reconstruction of the paleodepositional model. Seven facies associations were classified in the studied Tanjong Formation from 12 lithofacies components, interpreted as environments ranging from fluvial-deltaic to shallow marine: FA1—Floodplain, FA2—Fluvial channel, FA3—Coastal peat mires, FA4—Tidal flat, FA5—Delta front, FA6—Mouth bar, and FA7—Upper shoreface. Evaluation of the C/N ratio ranged between 4 and 48, and the total sulfur content ranged from 0.5 to 3. Elemental CHNS analysis suggests that the organic matter extracted from the coal and mudstone originated from terrestrial plants and fresh marine plankton. Accordingly, the three most prevalent FTIR spectra from the coal and mudstone samples were the OH- functional group stretching, the absorption spectrum of aromatic C=C stretching, and aromatic in-plane/out-of-plane C-H bending. Terrestrially derived organic matter within the examined samples was further validated by the predominance of aromatic compounds, and the palynological analysis indicated a back-mangrove freshwater pollen assemblage and a lower coastal plain setting proximal to the marine environment. The integrated findings from this research are vital in reconstructing a paleodepositional environment model that will improve the predictability of the petroleum system mechanisms and the future hydrocarbon potential for conventional petroleum exploration. [ABSTRACT FROM AUTHOR]

Detecting the top and base subsea permafrost from 2D seismic reflection data in shallow marine settings is a non‐trivial task due to the occurrence of strong free surface multiples. The potential to accurately detect permafrost layers on conventional 2D seismic reflection data is assessed through viscoelastic modelling. Reflection imaging of permafrost layers is examined through the evaluation of specific characteristics of the subsurface, acquisition parameters and their impact. Results show that limitations are related to the principles of the method, the intrinsic nature of the permafrost layers, and the acquisition geometry. The biggest challenge is the occurrence of free surface multiples that overprint the base permafrost reflection, with the worst‐case scenario the case of a thin layer of ice‐bonded sand. Wedge models suggest that if the base permafrost is dipping, it would intersect internal and free surface multiples of the seafloor and the top permafrost and be detected. Also, the amplitude ratio of the base permafrost reflection and the multiples decreases with the increasing thickness of permafrost. Therefore, the crosscutting relationship between the reflection at base permafrost reflection and the multiples might not be enough to detect the base permafrost for thicker permafrost layers. Finally, the experiment results show that, for partially ice‐bonded layers, the attenuation combined with the low reflectivity of the basal interface limits the likelihood to resolve the base permafrost, especially for thick permafrost layers. [ABSTRACT FROM AUTHOR]

The study of fossil diatom assemblages constitutes an effective tool for inferring past water conditions. Several studies from around the world suggest the Miocene was a key period in the evolutionary history of diatoms. However, Miocene diatom assemblages from the southwestern Atlantic Ocean are nearly unknown. This study aims to provide a palaeoenvironmental interpretation of the analysed succession. Additionally, to highlight temporal and regional changes, the assemblage is compared with known modern and fossil assemblages from Patagonia and other regions of the world. Finally, we provide a detailed description of the extinct diatom taxa recognised throughout the sedimentary succession. A total of 36 diatom taxa were recognised in the 25 analysed samples. Despite the evidence from sedimentology and macro-palaeontology indicating temporal changes from inner shelf to estuarine environments, the diatom assemblages are dominated by the coastal marine Paralia sulcata sensu lato throughout the succession. An important freshwater input into the coastal system is interpreted from our results reflecting more humid climatic conditions when compared with modern diatom assemblages from the same location. In addition, four extinct species were recognised: Thalassiosira cf. yabei , Pseudopodosira westii , Rhaphoneis diamantella, and Lancineis rectilatus. The presence of R. diamantella and L. rectilatus in the analysed deposits would imply an expansion of their geological range. • First diatom analysis for the Late Miocene Puerto Madryn Formation. • P. sulcata (s.l.) is the dominant taxon. • Diatom assemblages suggest freshwater supply to the inner shelf. • R. diamantella and L. rectilatus imply an expansion of their age ranges. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Sedimentological Society of Japan / Taisekigaku Kenkyu is the property of Sedimentological Society of Japan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most previous studies focused on the redox state of the deep water, leading to an incomplete understanding of the spatiotemporal evolution of the redox‐stratified ocean during the Ediacaran–Cambrian transition. In order to decode the redox condition of shallow marine environments during the late Ediacaran, this study presents I/(Ca + Mg), carbon and oxygen isotope, major, trace, and rare earth element data of subtidal to peritidal dolomite from the Dengying Formation at Yangba, South China. In combination with the reported radiometric and biostratigraphic data, the Dengying Formation and coeval successions worldwide are subdivided into a positive δ13C excursion (up to ~6‰) in the lower part (~551–547 Ma) and a stable δ13C plateau (generally between 0‰ and 3‰) in the middle‐upper part (~547–541 Ma). The overall low I/(Ca + Mg) ratios (<0.5 μmol/mol) and slightly negative to no Ce anomalies (0.80 < [Ce/Ce*]SN < 1.25), point to low‐oxygen levels in shallow marine environments at Yangba. Moreover, four pulsed negative excursions in (Ce/Ce*)SN (between 0.62 and 0.8) and the associated two positive excursions in I/(Ca + Mg) ratios (up to 2.02 μmol/mol) are observed, indicative of weak oxygenations in the shallow marine environments. The comparison with other upper Ediacaran shallow water successions worldwide reveals that the (Ce/Ce*)SN and I/(Ca + Mg) values generally fall in the Precambrian range but their temporal trends differ among these successions (e.g., Ce anomaly profiles significantly different between Yangba and the Yangtze Gorge sections), which point to low oxygen levels with high redox heterogeneity in the surface ocean. This is consistent with the widespread anoxia as revealed by low δ238U values reported by previous studies. Thus, the atmospheric oxygen concentrations during the late Ediacaran are estimated to be very low, similar to the case during the most Mesoproterozoic to early Neoproterozoic period. [ABSTRACT FROM AUTHOR]

A mid-Permian (late Kungurian) micro-dolerite dyke/sill complex located at Kinghorn Point intruded into the then unconsolidated upper Wandrawandian Siltstone of the lower Shoalhaven Group, southeastern Sydney Basin. The dark grey siltstone was deposited in the deeper part of a coastal seaway characterised by northward-directed paleocurrents, with a Cruziana ichnofacies, crinoid stem fossils and abundant glendonites indicating a cold climate. Thin periodic storm deposits, or tempestites, of fine-grained sandstone of volcanogenic origin are scattered through the siltstone. These paler sandy beds were probably derived from island volcanoes to the south or southeast, indicating that regional volcanism was pervasive during this glacial episode. Evidence for penecontemporaneous igneous emplacement into mid-Permian wet unconsolidated shallow marine sediments includes: destruction of primary sedimentary structures caused by extensive interaction and intermingling between the sedimentary and igneous materials, the presence of brecciated contacts and peperite, angular and rounded dolerite fragments in the siltstone, fluidisation and entrainment of the sediments into cooling and flow fractures in the magma, and the presence of tube-like flow features. There are also hyaloclastite and baked sediments along the contact margins, fumaroles and vesicles within both the sediment and magma. High vesiculation is characteristic of intrusion near the surface, and possibly extrusion at the sediment–water interface. The geochemistry of the intrusion, especially key element ratios of the high-field-strength, major and trace elements, is very different from that of the shoshonites of the nearby Permian (mid Wordian to Capitanian) Gerringong Volcanics, having much lower Zr/TiO2, Nb/Y, Nb/Zr, K2O, P2O5, Rb, Th, U, Y, Zr and Nb, and higher MgO, suggesting they are unrelated. This indicates that the Kinghorn Point intrusion was associated with an earlier intermediate pre-Gerringong Volcanics phase, or it may be distinctive and unrelated. Magmatic geochemical comparisons further afield along the northern Sydney Basin and Tamworth Fold Belt boundary coasts show that volcanism was pervasive during the Wandrawandian glacial episode and that regional mid-Permian mafic volcanism was well evolved in the southern Sydney Basin during sedimentation. A mid-Permian syndepositional dolerite intrusion at Kinghorn Point shows classical peperite and soft-sediment deformation features. Previously unreported mafic tuffaceous sandstone beds within the Wandrawandian Siltstone were probably derived from island volcanoes to the south or southeast. Geochemistry of the intrusion shows that it is not related to the mid Wordian to Capitanian Gerringong Volcanics. Regional volcanism was pervasive during the Wandrawandian glacial episode along the southeast Panthalassan margin of Gondwana. [ABSTRACT FROM AUTHOR]

Seismic investigation in marine gas‐bearing sediments often fails to get information below the acoustic mask created by free gas. To circumvent this problem, we combined collocated multichannel ultra‐high resolution seismic imaging, marine electrical resistivity tomography and core sampling to study the physical properties of gas‐bearing sediments in the Bay of Concarneau (France). We obtained sections of compression (P‐) wave velocity (VP${V_P}$) from the multichannel processing and 2D resistivity models from the marine electrical resistivity tomography data inversion. We observed low resistivity (∼0.5 Ω·m) and low VP${V_P}$ (∼1200 m/s) values where free gas was identified in the seismic data. We tested a joint processing workflow combining the 1D inversion of the marine electrical resistivity tomography data with the 2D P‐wave velocity through a structural coupling between resistivity and velocity. We obtained a series of 2D resistivity models fitting the data whilst in agreement with the VP${V_P}$ data. The resulting models showed the continuity of the geological units below the acoustic gas fronts, which are associated with paleo‐valley sediment infilling. We were able to demonstrate relationships between resistivity and velocity differing from superficial to deeper sediments. We established these relationships at the geophysical scale and then compared the results to data from core sampling (VP${V_P}$ and porosity). We inferred the porosity distribution from the marine electrical resistivity tomography data. At the core locations, we observed a good agreement between this geophysical scale porosity and the core data both within and outside the gas‐bearing sediments. This agreement demonstrated that resistivity could be used as a proxy for porosity where no VP${V_P}$ was available below gas caps. In these regions, the observed low resistivity showed a high porosity (60%–70%) down to about 10–20 m in depth, in contrast with the surrounding medium that has a porosity of less than 55%. These results support the hypothesis that failures inside the paleo‐valley sediment could control the gas migration. [ABSTRACT FROM AUTHOR]

Simple Summary: Original organics and soft tissues are known to persist in the fossil record. To date, these discoveries derive from a limited number of ancient environments, (e.g., rivers, floodplains), and fossils from rarer environments remain largely unexplored. We studied Cretaceous–Paleogene fossils from a peculiar marine environment (glauconitic greensand) from Jean and Ric Edelman Fossil Park in Mantua Township, NJ. Twelve samples were demineralized in acid to remove the mineral component of bone. This treatment frequently yielded products that are visually consistent with bone cells, blood vessels, and bone matrix from modern animals. Fossil specimens that are dark in color exhibit excellent microscopic bone preservation and yielded a greater recovery of original soft tissues, whereas light-colored specimens exhibit poor microscopic preservation and yielded few to no soft tissues. Additionally, a well-preserved femur of a marine crocodilian was found to retain original bone protein by reactions with antibodies. Our results: (1) corroborate previous findings that original soft tissue and proteins can be recovered from fossils preserved in marine environments, and (2) expand the range of ancient environments documented to preserve original organics and soft tissues. This broadens the suite of fossils that may be fruitful to examine in future paleomolecular studies. Endogenous biomolecules and soft tissues are known to persist in the fossil record. To date, these discoveries derive from a limited number of preservational environments, (e.g., fluvial channels and floodplains), and fossils from less common depositional environments have been largely unexplored. We conducted paleomolecular analyses of shallow marine vertebrate fossils from the Cretaceous–Paleogene Hornerstown Formation, an 80–90% glauconitic greensand from Jean and Ric Edelman Fossil Park in Mantua Township, NJ. Twelve samples were demineralized and found to yield products morphologically consistent with vertebrate osteocytes, blood vessels, and bone matrix. Specimens from these deposits that are dark in color exhibit excellent histological preservation and yielded a greater recovery of cells and soft tissues, whereas lighter-colored specimens exhibit poor histology and few to no cells/soft tissues. Additionally, a well-preserved femur of the marine crocodilian Thoracosaurus was found to have retained endogenous collagen I by immunofluorescence and enzyme-linked immunosorbent assays. Our results thus not only corroborate previous findings that soft tissue and biomolecular recovery from fossils preserved in marine environments are possible but also expand the range of depositional environments documented to preserve endogenous biomolecules, thus broadening the suite of geologic strata that may be fruitful to examine in future paleomolecular studies. [ABSTRACT FROM AUTHOR]

Submarine karstic environments are complex and challenging to study. Seismic investigations usually have difficulty getting geological information because of a lack of penetration due to the high reflectivity of the calcareous substratum. To circumvent this problem, we studied how to combine marine electrical resistivity tomography (MERT) with geotechnical data to investigate the porosity structure from the geotechnical to the geophysical scale. We applied the technique to the submarine karstic plateau of Banc de Guérande (Saint‐Nazaire, France), which is mainly composed of hard calcarenite and sandy pockets. We obtained sections of two‐dimensional resistivity models from the MERT data inversion. We used existing geotechnical data on extracted cores at several boreholes close to the MERT profiles using a multi‐sensor core logging (MSCL) bench. We used porosity proxies derived from Archie's law and porosity data from the MSCL inferred from gamma density measurements on the core to combine the data of very different scales (metre for MERT and centimetre for MSCL). The comparison between measurements showed a good similarity between in situ MERT and borehole MSCL data at depths greater than ∼10 m below the seafloor. A larger difference was observed close to the seabed, where the MERT porosity was higher than the MSCL porosity. The extraction of water‐saturated cores and the numerous core fractures could explain this difference near the surface. The results were analysed with respect to the scale difference between geophysical and geotechnical data. The conclusions suggested that the difference between MERT and MSCL porosities could be testified from the local heterogeneity of the soil and indicated whether the surrounding substratum was more porous (and thus fractured or dissolved) than the core or vice versa. The study highlighted the necessity of an excellent collocation of the data to retrieve reliable information from the comparison between geophysical and geotechnical data. [ABSTRACT FROM AUTHOR]

Understanding how depositional environments within a sedimentary system redistribute and sequester sediment is critical for interpreting basin-scale provenance trends. However, sedimentary source-to-sink models commonly examine temporal changes and do not consider how variation in sedimentation processes across a dispersal pathway may result in contrasting provenance signatures. In this paper, we demonstrate a down-paleoslope shift in detrital zircon provenance signatures correlated with shallow-marine lithofacies patterns from the Upper Cretaceous La Anita Formation and underlying continental slope lithofacies of the Alta Vista Formation (Magallanes-Austral Basin, southern Patagonia). New stratigraphic, sedimentologic, and lithofacies analysis results from the La Anita Formation suggest an upward shoaling succession, from a 1) storm-influenced shoreface, 2) fluvially dominated, wave-influenced delta, and a 3) high-energy, gravelly foreshore. Stratigraphic sections are paired with U-Pb detrital zircon sandstone samples (N = 20; n = 5,219), which provide both maximum depositional ages and provenance characteristics. While all samples contain abundant zircon derived from the Andean volcanic arc (ca. 145–75 Ma), the amount from both Jurassic distal volcanic massifs (ca. 188–162 Ma) and recycled orogenic sources exhumed during the advance of the Cretaceous fold-and-thrust belt (>200 Ma; 157–142 Ma) vary with changes in depositional environment. We argue that down-paleoslope, systematic enriching of local fold-and-thrust belt material within the La Anita Formation is reflective of progressive mixing of grains transported via shallow-marine processes, while distally enriched fluvio-deltaic transported zircons were sourced from large, regional catchments. This suggests that competition between transport processes across a shallow and marginal marine sequence of rocks affects the resulting provenance signatures recorded within a single stratigraphic succession. These data also detail the degree of sediment pathway connectivity between shallow-marine sources and deep-marine sinks. Detrital zircon results from muddy continental slope facies of the Alta Vista Formation are made up entirely locally derived material, while zircon results from deep-water, sand-rich channel facies of the Formation are indistinguishable from coeval fluvio-deltaic zircon signatures. This implies that continental shelf-to-slope connectivity in a sediment dispersal system, via submarine canyons or shelf-edge delta progradation, is necessary for detrital zircon distributions from the shallow-marine realm to propagate into the deeper marine.

The late early Permian coincided with a short-lived cold episode in Western Australia, which occurred long after the demise of late Paleozoic ice sheets, and is manifested by conspicuous dropstones in corresponding marine strata. In the northern Perth Basin, this time interval is represented by the Carynginia Formation, which has long been regarded as a record of low-energy marginal-marine sedimentation. The low-diversity body-fossil content and impoverished trace-fossil assemblages in the formation were recognised as evidence of low salinities, low dissolved-oxygen levels and high suspended-sediment concentrations presumably related to freshwater influxes into a restricted basin. However, sedimentary facies indicative of river processes have yet to be documented to explain the sedimentological and paleontological character of the formation. This study examines an overlooked sandstone-rich interval of the Carynginia Formation in the Irwin Sub-basin, a marginal half graben faulted against crystalline basement of the Yilgarn Craton and forming part of a series of late Paleozoic intracratonic rift basins in Western Australia. Facies analysis indicates that the lower part of the interval is dominated by storm-generated deposits containing extraformational pebbles and boulders. These deposits are interpreted as recording lower-shoreface sedimentation under the influence of seasonal sea ice, and constitute a shallower, sandstone-rich equivalent of mudstone-prone strata that otherwise characterise the Carynginia Formation. The upper part of the interval consists of river-borne deposits representing friction-dominated deposition of a river-mouth bar, the first direct record of deltaic sedimentation in the Carynginia Formation. The stratal organisation of mouth-bar bedsets is likely the result of successive sediment-laden pulses related to seasonal floods in a shallow marine basin, and the autogenic evolution of the mouth-bar complex in response to fluctuating river discharge and compensational stacking. Formative runoff events were arguably responsible for reductions in salinity and the introduction of turbid buoyant plumes into the shallow sea that were adverse to faunal development. A fluvial influence may explain the sedimentary character and fossil content of coeval mudstone-prone formations in Western Australian rift basins, especially in the vicinity of cratonic margins. The lower Permian (late Artinskian–Kungurian) mudstone-prone Carynginia Formation in the northern Perth Basin has long been regarded as the record of low-energy, marginal-marine conditions in a cold-water seaway. The low-diversity fossil content in the lower part of the formation indicates stressed physico-chemical conditions influenced by freshwater, sediment-laden influxes. The described mouth-bar deposits are the first direct evidence of deltaic sedimentation in the Carynginia Formation, demonstrating that river outflows likely controlled water chemistry and impacted faunal development. [ABSTRACT FROM AUTHOR]

Endogenous biomolecules and soft tissues are known to persist in the fossil record. To date, these discoveries derive from a limited number of preservational environments, (e.g., fluvial channels and floodplains), and fossils from less common depositional environments have been largely unexplored. We conducted paleomolecular analyses of shallow marine vertebrate fossils from the Cretaceous–Paleogene Hornerstown Formation, an 80–90% glauconitic greensand from Jean and Ric Edelman Fossil Park in Mantua Township, NJ. Twelve samples were demineralized and found to yield products morphologically consistent with vertebrate osteocytes, blood vessels, and bone matrix. Specimens from these deposits that are dark in color exhibit excellent histological preservation and yielded a greater recovery of cells and soft tissues, whereas lighter-colored specimens exhibit poor histology and few to no cells/soft tissues. Additionally, a well-preserved femur of the marine crocodilian Thoracosaurus was found to have retained endogenous collagen I by immunofluorescence and enzyme-linked immunosorbent assays. Our results thus not only corroborate previous findings that soft tissue and biomolecular recovery from fossils preserved in marine environments are possible but also expand the range of depositional environments documented to preserve endogenous biomolecules, thus broadening the suite of geologic strata that may be fruitful to examine in future paleomolecular studies.

Carboniferous units in southern Mexico consist of mixed carbonate-volcaniclastic facies representing shallow marine environments, from the middle ramp to shallow subtidal environments in the inner ramp. The Tournaisian-Visean Santiago Formation is characterized by the dominance of mixed clastic and bioclastic sediments in a mid-ramp setting without a supply of volcanic material within the basin. Instead, the newly reported locality of the Mississippian-Pennsylvanian Ixtaltepec Formation is a mixed succession of volcaniclastic and carbonated sediments deposited under a tidal influence in the middle to the inner ramp. The age is determined to be late Visean and early Serpukhovian (∼333-325 Ma) based on the presence of Actinoconchus lamellosus , Syringothyris sp., and Punctospirifer sp. and corroborated by geochronological data. This study provides new evidence of Carboniferous volcanism in the sediment-sources area in southern Mexico. Volcanic activity in the area is linked to the subduction of the oceanic crust of the Rheic Ocean, which resulted in the formation of magmatic arcs on the Gondwanan realm and the assembly of Pangea. During the Early Mississippian to early Permian, extensive areas of the northwest of South America and southwest of North America were covered by epicontinental seas. Sedimentation in the area was mainly characterized by shallow clastic-carbonate-dominated environments and deep marine settings, where basins within the peri-Gondwana Terranes received volcanic detritus from the North Gondwana and western Pangea arcs. • Carboniferous successions in southern Mexico comprise mixed carbonate–siliciclastic sediments that represent environments from the middle ramp to inner ramp. • The Mississippian-Pennsylvanian Ixtaltepec Formation is characterized by a mixing of volcaniclastic sediment with carbonate-siliciclastic sediment. • The Ixtaltepec Formation was deposited under a tidal influence. • Volcanogenic sediments are interpreted as pyroclastic surges and airfall deposits. • Volcanic activity is linked to the subduction of the oceanic crust of the Rheic Ocean and subsequent closure, which resulted in the formation of magmatic arcs on the Gondwanan realm. [ABSTRACT FROM AUTHOR]

Sedimentological and palynostratigraphical studies were performed on 189 ditch-cutting samples composited at 50 ft intervals from four well sections located in KW field, onshore western Niger Delta Basin, Nigeria, using sieving and visual microscopic observations, hydrochloric and hydrofluoric acids digestion methods to determine their lithological character and palynologic content of the sedimentary successions. The basis of these data is to interpret the lithofacies and biostratigraphy, establish the age of the strata, establish the palynological zones and infer the environments of deposition. Five lithofacies delineated based on the sedimentological study were very coarse sand, coarse to fine sand, shaly sand, muddy sand, and sandy to silty shale. The age of the sedimentary successions ranges from Early Miocene to Pliocene based on the bio-assemblages of these key species. The Early Miocene age is characterized by the occurrence of Magnastriatites howardi , Psilatricolporites triangularis , Praedapollis africanus , Pachydermites diederixi , Spirosyncoilpites spiralis , Praedapollis flexibility , Racemonocolpites hians , Verrutricolporites rotundiporus , Verrutricolporites microporus , and Psilatricolporites divisus. The Middle Miocene age is characterized by the FAD of Crassoretitriletes vanraadshooveni , the occurrence of Belskipollis elegans , in association with Striatricolporites catatumbus , Verrutricolporites rotundiporus , Verrutricolporites microporus , Crassoretitriletes vanraadshooveni , Racemonocolpites hians , Retibrevitricolpites obodoensis , and Retibrevitricolpites protrudens. The Late Miocene age is characterized by the occurrence of Multiareolites formosus , Cyperaceaepollis sp., Stereiosporites sp., Peregrinipollis nigericus , Gemmamonoporites sp. ( Cleistopholis patens) , Laevigatosporites sp., Verrutricolporites sp., Nymphaeapollis clarus , and Verrutricolporites usmensis. The Pliocene age is characterized by the basal occurrence of Retistephenocolpites gracilis in association with Nymphaeapollis clarus , Cyperaceaepollis sp., Laevigatosporites sp., Verrutricolporites sp., and Crassoretitriletes vanraadshooveni. The boundary between the Early Miocene and Middle Miocene from the studied oil well sections is marked by the first appearance datum (FAD) and numerical maximum occurrence of Striatricolporites catatumbus and Belskipollis elegans and FAD of Crassoretitrilettes vanraadshooveni. The boundary between the Middle and late Miocene is defined by the LAD of Verrutricolporites rotundiporus, the quantitative top and numerical maximum occurrence of Racemonocolpites hians , and the numerical maximum occurrence of Zonocostites ramonae . The boundary between the late Miocene and the Early Pliocene is marked by the first appearance datum (FAD) and the numerical maximum occurrence of Retistephenocolpites gracilis, the numerical maximum occurrence of Echiperiporites icacinoides , and the highest abundance of Monoporites annulatus. Four palynozones PAZ-1, PAZ-2, PAZ-3, and PAZ-4, and ten sub-zones were erected. Finally, Fluvial-coastal to shallow marine environments of deposition were inferred for the sedimentary successions using sedimentological study, nature of organic matter, and association of key environmentally-sensitive biomarker species., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (© 2023 The Authors.)

The shallow marine channels and fans in the Yinggehai Basin have huge hydrocarbon exploration potential. The depositional features and filling processes of the submarine channel and fan system during 10.5–7.2 ma were studied based on seismic data, cores, well curves, and lab data. (1) Five depositional elements were recognized in the channel system, including PSC, MSC, DSC, levee, and abandonment fill, and the deposits show the typical sedimentary structure of debris flow. The filling process of the channel system was divided into three stages based on deposits supply intensity. The stages were made up of several filling units, and each unit possessed at least one complete channelized depositional succession. (2) The fan system was developed under the large-scale "U" shaped feeding canyon, and its filling process was divided into two stages, the shape and distribution were controlled by shelf break and syn-sedimentary faults in the early stage, and was influenced by the localized changes of paleogeomorphology in late stage. The influence factors for the development of gravity-driven systems were summarized into two levels: regional depositional environment changes and localized distinctive geologic settings. The former one controlled the development of shallow water gravity-driven deposits in the whole basin, mainly including rapid falling of sea-level, moderate subsidence rate, and stable deposits supply. The latter one controlled the morphology and distribution of depositional elements in gravity-driven systems. The pre-existing banded low terrain induced by blind faults controlled the shape of the confined channel, and variable faulting intensity in different segments of the syn-sedimentary fault and localized paleogeomorphology changes influenced the distribution of channels and inner fan in the fan system. The study of deposition features, internal architecture, and controlling factors may provide a reference for further exploration in this area and a deeper understanding of gravity-driven processes in shallow marine. • The depositional elements were classified for the channelized and fan systems. • The internal architectures and filling processes of the channel and fan systems were figured out. • The sedimentary features in shallow marine gravity-driven systems were discussed. • The effects of regional depositional environment change, localized tectonic activities, and paleogeomorphology on shallow marine gravity-driven deposits were discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • New foraminifer and ostracod data encountered verify a late Ypresian to Lutetian age. • The relative sea-level changes are governed by eustacy and local tectonics. • The flora is comparable to the middle-?late Eocene flora of the Çankırı-Çorum Basin. • A warm and humid climate favoured the establishment of Nypa mangroves along the coast. This study presents the stratigraphy, biostratigraphy and palaeoecology of a 420- m thick sequence of the Mamuca Formation (Dümrek Basin, Eskişehir, Turkey). The age for the strata of the Mamuca Formation in the Çakıroğlu Creek section is narrowed to late Ypresian-Lutetian (early-middle Eocene) by benthic foraminifera (Nummulites planulatus, N. burdigalensis, Assilina placentula, A. laxispira and A. cuvillieri), planktonic foraminifera (Acarinina bulbroki , Acarinina rohri and Acarinina topilensis) and ostracoda (Eopaijenborchella longicosta and Bairdia gliberti). The sedimentation started in coastal conditions and changed basinward into a shallow marine environment. The palynological assemblage is documented by frequency of palms Spinizonocolpites , Proxaperties and Longapertites , and unknown botanical affinity of Psilodiporites iszkaszentgyoergyi linking them to mangrove environments, along with pteridophytic spores indicating coastal sedimentation. Subsequently, a relative sea-level rise is obvious, leading to a sharp increase in the abundance of organic-walled dinocysts and a decrease in mangroves, almost died-off. The following faulting caused a tectonically triggered subsidence of the basin and led to an environment that deepened even more, provided that it was still shallow marine conditions that allowed the accumulation of coarse-grained sediments, devoid of fossil. Palynological data, stable isotopes (δ18O and δ13C) and quantitative palaeoclimate estimates point to a warm (probably tropical) and humid climate during the late Ypresian and Lutetian. [ABSTRACT FROM AUTHOR]

A multidisciplinary approach based on lithostratigraphy, petrography, modal composition and geochemistry was performed for the first time, to study the Early Ediacaran Skoura Turbidites (EEST) of the Skoura inlier, Central High Atlas. It represents widely distributed turbidite successions up to 8 km in thickness. A total of twelve lithofacies types have been distinguished, spread in four profiles, and grouped in three major depositional environments: shallow delta complex (FA1), submarine channel (FA2), and deep-sea fan (FA3). The paleogeographic distribution of the EEST may indicate basin depth changes related to the onset of convergence. Petrographic and modal analyses of EEST reveal greywacke and lith-arenite lithologies displaying similar clast composition, mainly comprising quartz and lithic fragments. Volcanic, plutonic, and metamorphic rocks have been exposed in the source areas feeding the Skoura basin. On Q-F-L diagram, EEST have characteristics of a recycled orogen, suggesting their derivation from an active arc setting. Geochemical data of EEST samples display similar SiO 2 and Al 2 O 3 abundances, with relatively intermediate compositions. Most of the studied samples demonstrate their derivation from a composite of oceanic island and continental arc systems providing felsic and mafic to intermediate detritus to the Skoura basin. Rare-earth element patterns show features similar to those of sandstones in modern active margin zones. The EEST rocks are similar with other Early Ediacaran sediments of the Saghro Group in the Anti-Atlas belt. This architecture suggests deposition of the EEST in an orogenic basin developed in a back-arc setting during the Early Ediacaran time. • Deep sea and shallow marine environments for the Early Ediacaran turbiditic rocks in the Skoura inlier. • Stratigraphic and geochemical features of the Skoura Turbidites are linked to back arc setting. • Geochemical characters of the Skoura Turbidites indicate a mixture of felsic and mafic sources. • The Skoura Turbidites line up with the Early Ediacaran geodynamic evolution at the Northwestern Gondwana margin. [ABSTRACT FROM AUTHOR]

The Hawaz Formation comprises a siliciclastic, shallow to transitional marginal marine succession, deposited on the north-western cratonic margin of Gondwana during the Middle Ordovician. This unit is well documented in the north central part of the Murzuq Basin, where it is often dramatically truncated by Late Ordovician glaciation unconformities, generating a major discontinuity, not only in the studied area but also across the whole Saharan Platform of North Africa. The Hawaz Formation is particularly relevant as one of the two major oil-bearing reservoirs in the Murzuq Basin. However, Late Ordovician erosion ensures that its present configuration bears very little relation to the original sedimentary architecture and, consequently, there is a need for a detailed large-scale correlation and sedimentary reconstruction of the Hawaz in order to improve subsurface management of this reservoir unit. The present study was developed from a previous sedimentological characterization of the Hawaz Formation, based on subsurface data provided by 35 wells. This sedimentological background provided the basis for the reconstruction of the sedimentary architecture of this unit by means of eight correlation panels oriented along both sedimentological dip (NNW-SSE) and strike (WSW to ENE). In addition, a series of Gross Depositional Environment (GDE) maps were also generated with the aim of providing insight into the lateral distribution of facies belts within the framework of a sequence stratigraphic-based reservoir zonation. The results of this study suggest that the Hawaz Formation was deposited in a relatively protected or embayed shoreline with multiple bays/estuaries as the main entry points for sediment into the basin, most likely influenced by the effects of pre-existing north-northwest to south-southeast Pan-African structures controlling local accommodation space and reactivated during Ordovician times. Correlation panels and GDE maps also show the Hawaz Formation to be an extensive and continuous reservoir across the studied area, deposited in a broadly extensive subtidal to intertidal paralic environment, with very few or possibly no modern sedimentary analogues. • Multidisciplinary study based on well data comprising conventional wireline logs, cores, image logs and seismic data. • Reconstruction of the sedimentary architecture of the Hawaz Fm. along both sedimentological dip and strike direction. • Gross Depositional Environment (GDE) maps of a Middle Ordovician embayment based on a sequence stratigraphic reservoir zonation. • Deposition of nearshore subtidal to intertidal deposits in an embayed shoreline controlled by eustasy and local tectonics. [ABSTRACT FROM AUTHOR]

The roughly 6 m thick limestone–green shale alternation within the lignite-bearing Giral Member of the Barmer Basin corresponds to a marine flooding event immediately after the Paleocene–Eocene transition. A detailed characterization of the glauconite using Electron Probe Micro Analyzer (EPMA), X-Ray Diffraction (XRD), Mössbauer and Field Emission Gun-Scanning Electron Microscope (FEG-SEM) reveals its origin in the backdrop of prevailing warm climatic conditions. The glauconite pellets vary from fine silt-sized to coarse sand-sized pellets, often reaching ~60% of the rock by volume. Mineralogical investigation reveals a 'nascent' to 'slightly evolved' character of the marginal marine-originated glauconite showing considerable interstratification. The chemical composition of the glauconite is unusual with a high Al2O3 (>10 wt%) and moderately high Fe2O3(total) contents (>15 wt%). While the K2O content of these glauconites is low, the interlayer sites are atypically rich in Na2O, frequently occupying ~33% of the total interlayer sites. The Mössbauer spectrum indicates 10% of the total iron is in ferrous form. High tetrahedral Al3+ of these glauconites suggests a high-alumina substrate that transformed to glauconite by octahedral Al-for-Fe substitution followed by the addition of K into the interlayer structure. The unusually high Na2O suggests the possibility of a soda-rich pore water formed by the dissolution of alkaline volcanic minerals. The Giral glauconite formation could have been a part of the major contributors in the Fe-sequestration cycle in the Early Eocene shelves. Warm climate during the Early Eocene time favored the glauconitization because of the enhanced supply of Fe, Al, and Si and proliferation of an oxygen-depleted depositional environment. [ABSTRACT FROM AUTHOR]