Implications For Depositional Environment Research Articles

Magnetic mineral characterization of the easternmost Indus Molasse sedimentary succession, Ladakh Himalaya: Implications for depositional environment and provenance

Magnetic mineral characterization of the easternmost Indus Molasse sedimentary succession, Ladakh Himalaya: Implications for depositional environment and provenance

Machine learning models to predict rare earth elements distribution in Tethyan phosphate ore deposits: Geochemical and depositional environment implications

The global market for rare earth elements (REE) is growing rapidly, driven by rising demand and limited production sources, prompting interest in recovering REE from secondary sources such as phosphate deposits. The Tethyan belt, extending across North Africa and the Middle East contains substantial Upper Cretaceous to Eocene REE-rich phosphorite deposits but with limited geochemical data available. This study provides a novel machine-learning (ML) method to predict REE contents in these deposits and verify a useful geochemical classification based on the concentrations of nine major element oxides. Four ML models are developed to achieve this: eXtreme Gradient Boosting (XGBoost), Random Forest (RF), Support Vector Regression (SVR), and Decision Tree (DT). The datasets are divided geochemically into oxic and sub-oxic patterns and these are evaluated with the ML models separately and in combination to accurately predict light REE (LREE), heavy REE (HREE), and total REE contents (∑REE). For the oxic pattern dataset, Fe2O3 and K2O exhibit the highest feature importance consistent with a glauconite influence. For the sub-oxic pattern dataset, MnO and SiO2 exhibit the highest feature importance consistent with high terrigenous inputs (MnO), and silicification. The ML results support the importance of the local deposition environment in determining REE distributions in these deposits. Paleogeography, ocean-margin tectonics, sea-level oscillations, and marine currents exert influence on the local depositional environments. The eXtreme Gradient Boosting model generates the lowest REE prediction errors for all the datasets evaluated.

Geochemistry of Brown Detrital Limestone BedswWithin Sarmord Formation, Sulaimani, Kurdistan Region, Iraq: Implication for Depositional Environment, Provenance and Tectonic Setting

Fifteen samples of brown detrital limestone beds within the Sarmord Formation from the Imbricated Zone (Qaiwan and Barzinjah sections) and High Folded Zone (Zewe section), Kurdistan region, NE-Iraq were analyzed. The analysis includes the major oxides, trace elements, and rare earth elements (REEs) to find out their provenance, tectonic setting, and depositional environment. These beds are mainly composed of detrital limestone in which calcite and traces of quartz are confirmed by XRD and the microscopic study. Al2O3/TiO2, La/Sc, La/Co, Th/Sc, Cr/Th and Th/Cr ratios and {(TiO2 + V2O3) - (MgO/ (MgO + Al2O3)}, (TiO2 - Ni), (La/Th - Hf), (La/Sc - Co/Th) diagrams reveal sourcing from the mixed carbonate platform and felsic rocks. The ratios of major, trace, and REE with PAAS values fall within the range of felsic rocks, which agree with Cretaceous western Iraq (present Western Desert) as a source of these beds. The (Rb – Sr – Ba) ternary diagram and (Sr/Ba-Sr/Rb) diagram display the distribution of the samples between the continental margin and inland field. Tectonically, these detrital limestones are transported from the erosion of the interior of the Arabian platform into deep marine and interbedded with the green marl. The V/Cr, U/Th, Ni/Co, and Sr/Ca ratios and diagram of Al2O3-V indicate deposition under shallow marine oxic to the dysoxic environment and transported to the deep marine. The paleoclimate index C-value, Sr/Cu ratio, and SiO2 - (Al2O3 + K2O + Na2O) diagram indicates hot arid conditions. Paleosalinity ratios Rb/K and Sr/Ba imply brackish to marine water conditions.

Palynostratigraphy of Late Cretaceous subsurface sediment of southern Bornu Basin, Nigeria: Implications for depositional environments and palaeoclimatic predictions.

Sedimentary records are helpful in tracking ancient environments and climates. By analysing Late Cretaceous subsurface sediment from the Gaibu-1 Well in the southern Bornu Basin, Nigeria, predominantly arenaceous lithologies were identified, and five stratigraphic sub-divisions were recognised: Bima, Yolde, Gongila, Fika (Upper, Middle, and Lower members), and Gombe Formations. Palynozonation facilitated the identification of four assemblage zones (A1 – A4): A (1) Triorites africaensis, A (2) Cretacaeiporites scabratus/Odontochitina costata, A (3) Droseridites senonicus, and A (4) Syncolporites/Milfordia spp. These findings suggest that the subsurface Cenomanian – Maastrichtian (younger) successions were deposited in the inner continental shelf (4600–3420 m), middle continental shelf (3420-2300 m), and distal middle continental shelf (2300-1500 m) settings. This Late Cretaceous succession is characterised by monocolpate pollens resembling modern Cenomanian palms, Nypa vegetation in wet lowland habitats, and conifer vegetation in relatively dry hinterlands during the Turonian-Maastrichtian, all under a tropical to subtropical climate systems. The data advocate that the Late Cretaceous era was characterised by prevalent tropical to subtropical climates featuring warm and humid conditions. This aligns seamlessly with the recognised Cretaceous Palmae Province of Africa–Southern America. This research demonstrates the reliability of integrated sedimentological and palynozonation datasets for refining the current understanding of ancient depositional environments and climate.

Petrographical and Geochemical Studies of the Upper Cretaceous Sandstones in Wadi Feiran, West-Central Sinai, Egypt: Implications for Depositional Environment and Diagenesis

The main focus of this paper is on the sandstones from the Upper Cretaceous period found in the Wadi Feiran area. The study aims to investigate various aspects of the sandstones, including their petrographic characteristics such as textural maturity and mineralogical classification, as well as their paleoenvironment, diagenesis, and chemical composition. The results show that the sandstones are sub-mature and were formed in relatively shallow neritic environments. Based on their mineralogical composition, they are classified as quartz arenite. The paleoenvironmental analysis suggests that the sediments were deposited in an area of mild tectonic stability. During diagenesis, the sandstones underwent various physical and chemical stages. Analysis of their chemical composition indicates that they were deposited under relatively warm and slightly alkaline conditions in a relatively shallow and restricted medium, with major and trace components including Al2O3, SiO2, Fe2O3, CaO, MgO, K2O, Na2O, P2O5, Cl, SO3, Ti, Mn, Cu, Ni, and Sr.

Microfacies and stable isotope analysis of Kuldhar Member Limestone (Callovian–Oxfordian), Jaisalmer Basin, western Rajasthan: implications for depositional environment and diagenetic evolution

Microfacies and stable isotope analysis of Kuldhar Member Limestone (Callovian–Oxfordian), Jaisalmer Basin, western Rajasthan: implications for depositional environment and diagenetic evolution

Stable isotopes and rare-earth elements of carbonate rocks, Paleocene–Eocene Kolosh Formation, High Folded Zone, NE Iraq: implication for depositional environment and Diagenesis

Stable isotopes and rare-earth elements of carbonate rocks, Paleocene–Eocene Kolosh Formation, High Folded Zone, NE Iraq: implication for depositional environment and Diagenesis

Geochemical and mineralogical analysis of the Upper Cretaceous dolomitic phosphates at Queih Mine, Quseir, Central Eastern Desert, Egypt: depositional environment implications and pollution indices

Soon for the security of phosphorus world supply, which comes primarily from non-renewable sources, the moderate carbonate phosphates will need further geochemical multidiscipline investigations to participate in the phosphorous supply chains necessary to increase human productivity. Dolomitic phosphates represented the main carbonate phosphate rocks of the Upper Member of Duwi Formation, at Um Queih Mine, South-Western Quseir, that phosphate can be classified as intermediate grade phosphate ore. It was enriched in V, Ni, Mo, U, Cu, Cr, Cd, Co as well as Zn and their ratios indicated that the deposition occurred in anoxic environment (reducing conditions). Mineralogical investigations indicated that the studied phosphorites are composed of two main mineral phases; fluorapatite and non-phosphatic minerals (dolomite, calcite, pyrite, gypsum, and quartz). The petrographic examination revealed that these phosphorites are composed of phosphatic lithoclasts, phosphatic bioclasts, opaques, and quartz grains embedded in a cryptocrystalline phosphatic matrix. The parent rocks of the studied phosphorites represented by basaltic mafic provenance were affected by low chemical weathering and deposited under marine anoxic environment. The mineralogical and geochemical characteristics indicated that the studied phosphorites deposited in marine anoxic condition. The weathering of these rocks can be harmful to the surrounding environment owing to its content of pyrite and potentially toxic elements (PTEs), the EF (enrichment factor) gives extremely high enriched with Mo, Cd, and Se.

Palynofacies analysis of the JOG16N-8 borehole, K5 formation from the Maniamba Basin (middle Permian), Mozambique: A contribution for hydrocarbon exploration

The Maniamba Basin in Mozambique is surveyed mainly in regard to coal exploration. However, this basin is also known for containing well preserved fossil plants and vertebrate fossils that shed light to the understanding of Gondwana ecosystems. Nevertheless, organic matter analysis (palynofacies) and its implication for depositional environment and hydrocarbon source rock have not yet been performed. Here, we report for the first time in the Maniamba Basin, results from palynofacies analysis combined with thermal maturation and kerogen typification. Palynofacies analysis was applied on 69 samples from the sediments of the JOGN16N-8 borehole, K5 Formation (middle Permian).The results indicate that sediments are dominated by phytoclasts with less abundant sporomorphs and sparse amorphous organic matter (AOM). Three palynofacies were identified suggesting depositional settings in a general proximal and oxic lacustrine-fluvial deltaic environment. The dominance of opaque phytoclasts may be due to wildfires, oxidation conditions before or post deposition in proximity to terrestrial settings and an environment under obliquity cycle controlled monsoon climate. The organic matter composition combined with Spore Colour Index (SCI), pointed out the existence of an abundant type IV kerogen followed by type III in immature phase suggesting very little or no potential for gas exploration. Very few horizons suggest the existence of kerogen type II. This study, gives significant information for better understanding of the variation of organic matter, palaeoenvironment and source rock potential of the studied area.

Sedimentological and Petrographic Analysis of Side Wall Samples from the Niger Delta Basin, Nigeria: Implications for Depositional Environments and Reservoir Quality.

Sedimentological and Petrographic Analysis of Side Wall Samples from the Niger Delta Basin, Nigeria: Implications for Depositional Environments and Reservoir Quality.

Field and Sedimentological Studies of Nataco-Banda Sediments of Lokoja Formation, Southern Bida Basin, Nigeria: Implication for Depositional Environment

The study area falls within the Lokoja Formation of the Southern Bida Basin. The objective of this study was to evaluate the field characteristics and sedimentological parameters of depositional environment of the Nataco-Banda Sediments of Lokoja Formation, Southern Bida Basin, Nigeria using appropriate techniques such as granulometric and pebble morphometric analysis. Field studies revealed a repeated alternating sequence of conglomeratic and pebbly to coarse-grained sandstone and overbank fine sediment that is indicative of a braided fluvial source while the presence of crossbedding is suggestive of tidal influence. The morphometric analysis shows a fluvial setting where pebbles plot in the river area than the beach area. Environmental discrimination formulae for Y1, Y2 and Y3 indicated the dominance of Beach and Shallow agitated marine in both Y1 and Y2, respectively, while the almost equal percentage values of Y3 in both fluvial and shallow marine settings are highly suggestive of a shallow marine environment that is largely influenced by fluvial deposition.

Major and Rare Earth Element Characteristics of Late Paleozoic Coal in the Southeastern Qinshui Basin: Implications for Depositional Environments and Provenance.

To understand the geochemical characteristics of late Paleozoic coal in the Changzhi and Jincheng mining areas in the southeastern Qinshui Basin, major and rare earth element analyses were conducted through inductively coupled plasma–mass spectrometry (ICP–MS), X-ray fluorescence spectrometry (XRF), and proximate analysis. The results show that the study coals are bituminous A rank and anthracite C rank (Ro,ran: 1.6–3.24%) with low-ash, low-moisture, low-volatile, and low- to medium-sulfur characteristics. The main forms of sulfur in the study coals are organic sulfur, followed by pyritic sulfur, only some coals with high sulfur contents in the Taiyuan Formation (SGJ, WTP, FHS) are mainly pyritic sulfur, and the contents of sulfate sulfur are extremely low. The major elements of the late Paleozoic coal in the southeastern Qinshui Basin are mainly SiO2 (4.77%) and Al2O3 (3.64%), followed by Fe2O3 (1.22%), CaO (1.53%), FeO (0.48%), MgO (0.25%), Na2O (0.21%), P2O5 (0.18%), TiO2 (0.15%), and minor K2O (0.04%) (on a whole-coal basis). Through correlation analysis and cluster analysis, the occurrence states of major elements in the Shanxi and Taiyuan Formations are different. The average rare earth elements and yttrium (REY) value in the study area is 88.68 μg/g (on a whole-coal basis). The mean light REY (LREY)-to-heavy REY (HREY) ratio is 26.33. The mean values of δEu, δCe, Y, and Gd are 0.60, 0.99, 1.07, and 1.02, respectively. The Shanxi Formation is dominated by the L-type REY enrichment, while the Taiyuan Formation is dominated by the M–H-type REY enrichment. The fractionation degree of REY in the Taiyuan Formation is lower than that in the Shanxi Formation. Rare earth elements in Shanxi coal mainly occur in clay minerals, and some rare earth elements are adsorbed and enriched by vitrinite. Rare earth elements in Taiyuan coal mainly occur in clay minerals and pyrite, and some rare earth elements occur in inertinite. A warm, humid, low-salinity, oxidizing, and acidic environment was favorable for REY enrichment. The coal-forming environment was weakly oxidizing and reducing, and the paleosalinity of the water was relatively high during late Paleozoic coal deposition in the southeastern Qinshui Basin. The paleotemperature of the Shanxi Formation is higher than that of the Taiyuan Formation. The provenance is mainly from an upper crustal felsic source region, the source rocks are mainly post-Archean sedimentary and calcareous mudstones mixed with some granite and alkaline basalt from the Yinshan Upland, and the tectonic setting of the source area mainly includes island arcs and active continental margins.

Lithofacies characterisation of the Miocene Surma sediments in the Barak basin, western Manipur, India: Implications for depositional environment

The depositional environment of the Miocene Surma sediments of the Naga–Manipur hills around Nungba, western Manipur, India have been studied using lithofacies analysis technique. The entire assemblage of the Surma Group (Bhuban Formation) succession has been classified into six different lithofacies types. All these facies are well preserved in five measured vertical profile sections besides lithofacies schemes in respect of the Surma rocks of the study area. Overall intertidal to subtidal environment may be envisaged for the deposition of the Bhuban Formation sediments under the influence of storm processes.

Geology, petrology, and geochemistry of the Mesoproterozoic Kaimur Group of rocks of the Vindhyan Supergroup, Eastern India: implications for depositional environment and sequence stratigraphy

Geology, petrology, and geochemistry of the Mesoproterozoic Kaimur Group of rocks of the Vindhyan Supergroup, Eastern India: implications for depositional environment and sequence stratigraphy

Maceral Association in Coal-bearing Formation of Mae Than Coal Mine in Lampang, Thailand - Implication for Depositional Environment

The Mae Than Basin in Lampang Province contains low-ranked coal reserves of northern Thailand. Coal seams and ball clays were mined in the southern part of the basin. This study focuses on the coal petrography of coal samples collected from the upper coal seam in the Mae Than Coal Mine. Both the organic and inorganic constituents provide information on the nature and characteristics of the coal, reflecting the physical and chemical behaviors of coal. Petrological analysis reveals that the Mae Than coals contain more huminite than liptinite macerals, while inertinite is negligible. Huminite occurs mainly in the form of texto-ulminite, textinite, densinite, and gelinite. Liptinite consists of sporinite, cutinite, resinite, suberinite, liptodetrinite, and terpenite. The morphology of cutinite, sporinite, and the presence of terpenite indicate that the peat-forming vegetation may consist of conifers. In addition to the macerals, the coal samples contain a small to moderate amount of mineral matter. Silica and clay minerals are the main minerals found in the cavities and between the cracks of the coals. The assemblage of macerals and mineral matter indicates that the Mae Than coals were formed mainly from common peat-forming vegetation, possibly conifers, in a freshwater forest swamp or mire in a warm temperate climate. In addition, the high degree of preservation of the macerals indicates a high water table and suggests rheotrophic, anoxic, limnotelmatic to telmatic conditions during deposition.

Iron speciation in organic-rich shales from the Upper Triassic Yanchang Formation, Ordos Basin, Northern China: Implications for depositional environment

The iron (Fe) cycle is one of the most important marine and lacustrine geochemical cycles and is closely related to environmental redox conditions, which directly affects carbon, sulfur, phosphorus cycling. Analysis of Fe speciation (including Feox, Femag, Fecarb, and Fepy) of organic-rich shale samples provides new insights into the controversial redox conditions during the Chang 7 sedimentary period. Our results show that Fecarb and Fepy of the Chang 7 organic-rich shale are the main forms of reactive Fe pools, indicating that reactive Fe mainly existed in the form of Fe2+ in sediments. With a few exceptions, most samples fall into the ferruginous region in crossplots of Fepy/FeHR versus FeHR/FeT, indicating that pore water environments during early diagenesis were ferruginous accompanied by intermittent euxinic. Previous works examining the size of framboidal pyrite, the molar ratio of organic carbon and total phosphorus (P), and nitrogen isotope values suggest the bottom water environments conditions were oxic-suboxic accompanied by intermittent anoxic. We argue these patterns may be explained by the proximity of the redox boundary of depositional environment to the sediment–water interface during most of the Chang 7 period, with short-term fluctuations. Euxinic pore water conditions correspond to anoxic bottom water conditions and elevated total organic carbon (TOC) content, indicating that these environmental conditions would increase the flux of P diffused from sediments. As a result, lacustrine primary productivity would be elevated, creating conditions conducive to the accumulation of organic matter that is characteristic of the Chang 7 sedimentary period. This work will further our understanding of the accumulation mechanism of organic matter in the Chang 7 shale, the principal source rock for the Mesozoic oil-bearing system in the Ordos Basin.

Bone diagenesis of tetrapods from the Middle Triassic Tarjados Formation: implication for depositional environment and palaeoclimate

Bone diagenesis of tetrapods from the Middle Triassic Tarjados Formation: implication for depositional environment and palaeoclimate

Sedimentary facies of the Mesoproterozoic Srisailam Formation, Cuddapah basin, India: Implications for depositional environment and basin evolution

Sedimentary facies of the Mesoproterozoic (~1400−1327 Ma) Srisailam Formation, exposed in the Srisailam sub-basin in the northern part of the Cuddapah basin, India, were analyzed. It helped in identifying eighteen different facies that can be grouped into six facies associations (FA-I to VI) – alluvial fan/fan-delta, delta top, delta front, lacustrine, fluvial, and aeolian. Hinterland geology, integrated palaeomagnetic, geochemical and sedimentological observations, and inferred palaeohydrological condition and palaeoclimate indicate more control of tectonic regime on the evolution of the facies architecture. Analysis of vertico-lateral disposition of the identified facies suggests that the deposition of the Srisailam sediments was initiated in a number of fault-controlled isolated depocenters (riftogenic lakes). However, those isolated lakes were deep enough to allow the evolution of lacustrine and deltaic depositional regimes. Basin-wide lacustrine environment was established during subsequent rifting and regional peak subsidence (rift-climax) of the basin floor. Cessation of further basin subsidence facilitated progradation of fluvial sediments. During low-stage fluvial sediments were reworked locally by aeolian processes, and during protracted dry periods, aeolian regimes were established over considerable stretches of the Srisailam sub-basin.It is likely that the Srisailam half-graben, adjacent to the Nallamalai Fold Belt, was developed due to lithospheric doming and limited crustal stretching during a mantle upwelling event responsible for lamproite (alkaline) magmatism in the northern part of the Cuddapah basin. The evolution of the Srisailam rift-basin may be compared with the Cenozoic rift system of Europe, where rift development took place simultaneously with the orogenic activity in the Alps and Pyrenees. The style of sedimentation in the Srisailam sub-basin may be considered as a variant of the Newark-type lacustrine facies complex, and the tripartite basin filling model of half-graben lacustrine complexes may possibly be extended to the Mesoproterozoic era.

Sedimentological characteristics and mineralogical studies of some Cretaceous sandstones in Nigeria: implications for depositional environment and provenance

Sedimentological characteristics and mineralogical studies of some Cretaceous sandstones in Nigeria: implications for depositional environment and provenance

Trace element and isotope Geochemistry of Neoarchean carbonate rocks from the Dharwar craton, southern India: Implications for depositional environments and mantle influence on ocean chemistry

Neoarchean carbonate rocks of the Vanivilas Formation (2.7 Ga) occur extensively in greenstone belts of western Dharwar craton, are associated with banded Fe-Mn formations and clastic sediments including diamictites, preserve well-developed stromatolitic structures. We intend to understand the depositional environments of these carbonates, extent of oxygenation in shallow oceans and to examine the mantle and continent inputs to Neoarchean oceans. Depleted LREESN and slightly enriched HREESN patterns, Y/Ho > 28, La, Y and Eu spiking and varying Ce anomalies shown by most of the samples, are consistent with their marine origin. However, 4 samples exhibit negative Ce anomaly indicating presence of oxygen supporting the hypotheses of localised, protected, shallow marine oxygenation in redox stratified late Meso- to Neoarchean oceans. δ13C values are well preserved (mean = -0.27‰ (PDB)) similar to other Archean marine carbonates from other cratons and show no correlation with δ18O and Mn/Sr ratios. Whereas, the δ18O values (mean= -10.78‰) show considerable depletion and can be attributed to later interactions with diagenetic/meteoric fluids. The mantle dominated, yet continental affected Neoarchean ocean chemistry is apparent from Sr-Nd isotope systematics. The lowest 87Sr/86Sri of carbonates, 0.7024 reflects ocean water Sr isotopic composition at 2.7 Ga, is higher than the model seawater evolution curve of Shields and Veizer, (2002). Similarly, other recent studies on Archean carbonates and barites reported higher 87Sr/86Sri values. This is due to the existence of Paleoarchean continental crust subjected to chemical weathering resulting in increased continental flux than previously thought of. Range of ℇNd values (-8.39 to 5.83) suggest that the carbonates had variable contributions of Nd from a long term depleted mantle through hydrothermal fluids, as well as, from 3.5 Ga old continental crust in the Dharwar craton. The carbonates were deposited in the Neoarchean ocean at variable depths within the shelf and those deposited at shallower and deeper environments are characterized respectively, by inputs derived from chemical weathering of ≥3.5 Ga old continental crust and mantle through hydrothermal fluids associated with submarine volcanic activity.