Search Results (212)

The Southern Lhasa Terrane, as the southernmost tectonic unit of the Eurasian continent, has long been a focal area in global geoscientific research due to its complex evolutionary history. The Yeba Formation exposed in this terrane comprises an Early–Middle Jurassic volcanic–sedimentary sequence that records multiphase tectonic deformation. This study applies structural analysis to identify three distinct phases of tectonic deformation in the Yeba Formation of the Southern Lhasa Terrane. The D₁ deformation is characterized by brittle–ductile shearing, as evidenced by the development of E-W-trending regional shear foliation (S₁). S₁ planes dip northward at angles of 27–87°, accompanied by steeply plunging stretching lineations (85–105°). Both south- and north-directed shear-rotated porphyroclasts are observed in the hanging wall. ⁴⁰Ar-³⁹Ar dating results suggest that the D₁ deformation occurred at ~79 Ma and may represent an extrusion-related structure formed under a back-arc compressional regime induced by the low-angle subduction of the Neo-Tethys Ocean plate. The D₂ deformation is marked by the folding of the pre-existing shear foliation (S₁), generating an axial planar cleavage (S₂). S₂ planes dip north or south with angles of 40–70° and fold hinges plunge westward or NWW. Based on regional tectonic evolution, it is inferred that the deformation may have resulted from sustained north–south compressional stress during the Late Cretaceous (79–70 Ma), which caused the overall upward extrusion of the southern Gangdese back-arc basin, leading to upper crustal shortening and thickening and subsequently initiating folding. The D₃ deformation is dominated by E-W-striking ductile shear zones. The regional shear foliation (S₃) exhibits a preferred orientation of 347°∠75°. Outcrop-scale ductile deformation indicators reveal a top-to-the-NW shear sense. Combined with regional tectonic evolution, the third-phase (D3) deformation is interpreted as a combined product of the transition from compression to lateral extension within the Lhasa terrane, associated with the activation of the Gangdese Central Thrust (GCT) and the uplift of the Gangdese batholith since ~25 Ma. Full article

The Raohe subduction–accretion complex (RSAC) in the Wandashan Block, NE China, comprises ultramafic rocks, gabbro, mafic volcanic rocks, deep-sea and hemipelagic sediments, and trench–slope turbidites. We investigate the basalts within the RSAC to resolve debates on its origin. Zircon U-Pb dating of pillow basalt from Dadingzi Mountain yields a concordant age of 117.5 ± 2.1 Ma (MSWD = 3.6). Integrating previous studies, we identify three distinct basalt phases. The Late Triassic basalt (210 Ma–230 Ma) is characterized as komatites–melilitite, exhibiting features of island arc basalt, as well as some characteristics of E-MORB. It also contains high-magnesium lava, suggesting that it may be a product of a juvenile arc. The Middle Jurassic basalt (around 159 Ma–172 Ma) consists of a combination of basalt and magnesium andesite, displaying features of oceanic island basalt and mid-ocean ridge basalt. Considering the contemporaneous sedimentary rocks as hemipelagic continental slope deposits, it is inferred that these basalts were formed in an arc environment associated with oceanic subduction, likely as a result of subduction of the young oceanic crust. The Early Cretaceous basalt (around 117 Ma) occurs in pillow structures, exhibiting some characteristics of oceanic island basalt but also showing transitional features towards a continental arc. Considering the regional distribution of the rocks, it is inferred that this basalt likely formed in a back-arc basin. Integrating the formation ages, nature, and tectonic attributes of the various structural units within the RSAC, as well as previous research, it is inferred that subduction of the Paleo-Pacific Ocean had already begun during the Late Triassic and continued into the Early Cretaceous without cessation. Full article

The Jurassic Tamulangou Formation in the Hongqi Depression has favorable hydrocarbon generation conditions and great resource potential. This study systematically analyzes the geochemical characteristics and thermal evolution history of the source rocks using data from multiple key wells. The dark mudstone of the Tamulangou Formation has a thickness ranging from 50 to 200 m, with an average total organic carbon (TOC) content of 0.14–2.91%, an average chloroform bitumen “A” content of 0.168%, and an average hydrocarbon generation potential of 0.13–3.71 mg/g. The organic matter is primarily Type II and Type III kerogen, with an average vitrinite reflectance of 0.71–1.36%, indicating that the source rocks have generally reached the mature hydrocarbon generation stage and are classified as medium-quality source rocks. Thermal history simulation results show that the source rocks have undergone two major thermal evolution stages: a rapid heating phase from the Late Jurassic to Early Cretaceous and a slow cooling phase from the Late Cretaceous to the present. There are differences in the thermal evolution history of different parts of the Hongqi Depression. In the southern part, the Tamulangou Formation entered the hydrocarbon generation threshold at 138 Ma, reached the hydrocarbon generation peak at approximately 119 Ma, and is currently in a highly mature hydrocarbon generation stage. In contrast, the central part entered the hydrocarbon generation threshold at 128 Ma, reached a moderately mature stage around 74 Ma, and has remained at this stage to the present. Thermal history simulations indicate that the Hongqi Depression reached its maximum paleotemperature at 100 Ma in the Late Early Cretaceous. The temperature evolution pattern is characterized by an initial increase followed by a gradual decrease. During the Late Jurassic to Early Cretaceous, the Hongqi Depression experienced significant fault-controlled subsidence and sedimentation, with a maximum sedimentation rate of 340 m/Ma, accompanied by intense volcanic activity that created a high-temperature geothermal gradient of 40–65 °C/km, with paleotemperatures exceeding 140 °C and a heating rate of 1.38–2.02 °C/Ma. This thermal background is consistent with the relatively high thermal regime observed in northern Chinese basins during the Late Early Cretaceous. Subsequently, the basin underwent uplift and cooling, reducing subsidence and gradually lowering formation temperatures. Full article

The Erentaolegai silver deposit is located within the Derbugan metallogenic belt in the eastern segment of the Central Asia–Mongolia giant orogenic belt. The ore bodies are primarily hosted in the volcanic rocks of the Middle Jurassic Tamulangou Formation of the Mesozoic. The mineralization process of the deposit is divided into three stages: Stage I: Pyrite–Quartz Stage; Stage II: Sulfide–Quartz Stage; Stage III: Quartz–Manganese Carbonate Stage. This paper discusses the ore-forming fluids, ore-forming materials, and deposit genesis of the Erentaolegai silver deposits using fluid inclusions microthermometry, laser Raman spectroscopy, and H-O-S isotope analyses. Fluid inclusion microthermometry and laser Raman spectroscopy analyses indicate that the Erentaolegai silver deposit contains exclusively fluid-rich two-phase fluid inclusions, all of which belong to the H₂O-NaCl system. Homogenization temperatures of fluid inclusions in the three stages (from early to late) ranged from 257 to 311 °C, 228 to 280 °C, and 194 to 238 °C, corresponding to salinities of 1.91 to 7.86 wt%, 2.07 to 5.41 wt%, and 0.70–3.55 wt% NaCl equivalent, densities of 0.75 to 0.83 g/cm⁻³, 0.80 to 0.86 g/cm⁻³ and 0.85 to 0.89 g/cm⁻³. The mineralization pressure ranged from 12.2 to 29.5 MPa, and the mineralization depth was 0.41 to 0.98 km, indicating low-pressure and shallow-depth mineralization conditions. H-O isotope results indicate that the ore-forming fluid is a mixture of magmatic fluids and meteoric water, with meteoric contribution dominating in the late stage. The δ³⁴S values of metallic sulfides ranged from −1.8 to +4.0‰, indicating that the metallogenic material of the Erentaolegai silver deposit was dominated by a deep magmatic source. This study concludes that meteoric water mixing and subsequent fluid cooling served as the primary mechanism for silver mineral precipitation. The Erentaolegai silver deposit is classified as a low-sulfidation epithermal silver deposit. Full article

The Lower–Middle Jurassic of the Kuqa Depression consists of terrestrial clastic deposits containing coal seams and thick lacustrine mudstones, and is of great significance for oil and gas exploration. Based on the comprehensive analysis of core, well-logging, outcrop, and seismic data, the sequence stratigraphy, depositional systems, and the controlling factors of the basin filling in the depression are systematically documented. Four primary depositional systems, including braided river delta, meandering river delta, lacustrine, and swamp deposits, are identified within the Ahe, Yangxia, and Kezilenuer Formations of the Lower–Middle Jurassic. The basin fills can be classified into two second-order and nine third-order sequences (SQ1–SQ9) confined by regional or local unconformities and their correlative conformities. This study shows that the sedimentary evolution has undergone the following three stages: Stage I (SQ1–SQ2) primarily developed braided river, braided river delta, and shallow lacustrine deposits; Stage II (SQ3–SQ5) primarily developed meandering river, meandering river delta, and extensive deep and semi-deep lacustrine deposits; Stage III (SQ6–SQ9) primarily developed swamp (SQ6–SQ7), meandering river delta, and shore–shallow lacustrine deposits (SQ8–SQ9). The uplift of the Tianshan Orogenic Belt in the Early Jurassic (Stage I) may have facilitated the development of braided fluvial–deltaic deposits. The subsequential expansion of the sedimentary area and the weakened sediment supply can be attributed to the planation of the source area and widespread basin subsidence, with the transition of the depositional environments from braided river delta deposits to meandering river delta and swamp deposits. The regional expansion or rise of the lake during Stage II was likely triggered by the hot and humid climate conditions, possibly associated with the Early Jurassic Toarcian Oceanic Anoxic Event. The thick swamp deposits formed during Stage III may be controlled by the interplay of rational accommodation, warm and humid climatic conditions, and limited sediment supply. Milankovitch cycles identified in Stage III further reveal that coal accumulation was primarily modulated by long-period eccentricity forcing. Full article

This study conducted a spatiotemporal review of the coelacanth fossil record and explored its distribution and diversity patterns. Coelacanth research can be divided into two distinct periods: the first period, which is based solely on the fossil record, and the second period following the discovery of extant taxa, significantly stimulating research interest. The distribution and research intensity of coelacanth fossils exhibit marked spatial heterogeneity, with Europe and North America being the most extensively studied regions. In contrast, Asia, South America, and Oceania offer substantial potential for future research. Temporally, the coelacanth fossil record also demonstrates significant variation across geological periods, revealing three diversity peaks in the Middle Devonian, Early Triassic, and Late Jurassic, with the Early Triassic peak exhibiting the highest diversity. With the exception of the Late Devonian, Carboniferous, and Late Cretaceous, most periods remain understudied, particularly the Permian, Early Jurassic, and Middle Jurassic, where the record is notably scarce. Integrating the fossil record with phylogenetic analyses enables more robust estimations of coelacanth diversity patterns through deep time. The diversity peak observed in the Middle Devonian is consistent with early burst models of diversification, whereas the Early and Middle Triassic peaks are considered robust, and the Late Jurassic peak may be influenced by taphonomic biases. The low population abundance and limited diversity of coelacanths reduce the number of specimens available for fossilization. The absence of a Cenozoic coelacanth fossil record may be linked to their moderately deep-sea habitat. Future research should prioritize addressing gaps in the fossil record, particularly in Africa, Asia, and Latin America; employing multiple metrics to mitigate sampling biases; and integrating a broader range of taxa into phylogenetic analyses. In contrast to the widespread distribution of the fossil record, extant coelacanths exhibit a restricted distribution, underscoring the urgent need to increase conservation efforts. Full article

The Jiapigou mining district (>180 t Au) is an important gold district in China. For a long time, the ore genesis of the gold deposits in the Jiapigou district has been a subject of controversy and differing opinions, which has severely hindered metallogenic theories and mineral exploration. Here we present a comprehensive investigation including geology, fluid inclusions (FIs), and H–O–S isotopic data for the Naizhigou deposit in the Jiapigou district to elucidate the sources of orefluids and metals, as well as the metallogenic mechanism. The results show the following: (1) The Naizhigou deposit is characterized by quartz vein-type ores and is hosted in the Middle Jurassic granitic pluton. Native gold and sulfides were mainly deposited in the second stage (quartz–polymetallic sulfides) compared with the first (quartz–pyrite–molybdenite) and third (quartz–calcite) stages. (2) The FI studies indicated that the orefluids evolved from the early–main-stage CO₂–H₂O–NaCl system to the late-stage H₂O–NaCl system and have homogenization temperatures of 289–363, 210–282, and 124–276 °C and salinities of 4.1–20.9, 5.8–16.4, and 6.1–12.7 wt% NaCl equivalent, respectively. Fluid boiling and fluid mixing collectively controlled the precipitation of gold and ore-forming elements. (3) The δD values of the FIs hosted in quartz from the three stags range from −81 to −75 ‰, from −99 to −86 ‰, and from −110 to −101 ‰, while δ¹⁸O_water values of these FIs range from 5.3 to 5.9 ‰, from 1.1 to 5.2 ‰, and from −2.1 to −0.7 ‰, respectively. Pyrite samples from the three stages in the Naizhigou deposit have δ³⁴S values of 2.1 to 2.5 ‰, 3.1 to 4.3 ‰, and 3.8 to 3.9 ‰, respectively. The stable isotopes indicate that the orefluids and metals mainly originated from magma. A comparative study of regional observations reveals that the Naizhigou deposit is a magmatic-related mesothermal gold deposit, rather than a metamorphism-related orogenic gold deposit. The estimated ore-forming depths are 4.0–20.7 km, with exhumation depths of 4.1–5.5 km, which indicated that the deposit has been well preserved. Regionally, the new exploration strategies should place greater emphasis on work concerning ore-related plutons, ore-controlling faults, and hydrothermal alteration. Full article

The Caucasian Sea was among the vast tropical water masses that existed on Earth in the Mesozoic. The knowledge of Kimmeridgian–Hauterivian deposits from the central Western Caucasus can facilitate the understanding of the Caucasian paleogeography at the Jurassic–Cretaceous transition. Taking into account the scale of the study area and its geological complexity, a generalized synthesis of the published information seems to be an appropriate option to propose a tentative paleogeographical model. Some original field and laboratory studies, including the examination of the composition of Hauterivian alluvial sandstones, contribute to this model. Kimmeridgian–Hauterivian deposits crop out in the northern, western, and southern domains of the study area, but older rocks are exposed in its central and eastern parts. The Caucasian Sea covered the study area in the early Kimmeridgian, but a large land appeared in the late Kimmeridgian and existed until the end of the Hauterivian despite certain shoreline shifts. The land was eroded deeply, with exposure of pre-Upper Jurassic rocks, including Precambrian–Paleozoic crystalline complexes, and the sedimentary material was delivered to an alluvial plain on its periphery. The registered sea–land interplay was controlled tectonically. Full article

The Great Xing’ an Range is located in the eastern part of the Xing’ an-Mongolian Orogenic Belt, which is an important component of the Central Asian Orogenic Belt. To determine the emplacement age and petrogenesis of the granitoids in the Gegenmiao and Taonan areas of the central Great Xing’an Range, and to investigate its tectonic setting, petrographic studies, zircon U-Pb geochronology, whole-rock Sr-Nd isotopic analysis, zircon Hf isotopic analysis, and detailed geochemical investigations of this intrusion were carried out. The results indicate the following, in relation to the granitoids in the study areas: (1) The zircon U-Pb dating of the granitic rocks in the study areas yields ages ranging from 141.4 ± 2.0 Ma to 158.7 ± 1.9 Ma, indicating their formation during the Late Jurassic to Early Cretaceous; (2) the geochemical characteristics indicate that these rocks belong to the calc-alkaline series and peraluminous, classified as highly fractionated I-type granites with adakite features; (3) the Sr-Nd isotopic data show that the εNd(t) values of Gegenmiao granitic rocks are 2.8 and 2.1, while those of Taonan granitic rocks range from −1.5 to 0.7; (4) the Zircon εHf(t) values of the granitic rocks from Gegenmiao and Taonan vary from 2.11 to 6.48 and 0.90 to 8.25, respectively. They are interpreted to have formed through partial melting of thickened lower crustal material during the Meso-Neoproterozoic. The Gegenmiao and Taonan granitic rocks were formed in a transitional environment from post-orogenic compression to extension, which is closely associated with the Mongolia–Okhotsk tectonic system. Full article

The nocturnal, flightless camel crickets (Rhaphidophoridae) have a global distribution and are believed to have originated prior to the breakup of Pangea. We investigated the phylogeny and the timing of the radiation of East Asian species with mitogenomic data. Initially we analyzed a large taxon dataset (n = 117) using available partial mitochondrial and nuclear DNA sequences to confirm the monophyly of subfamilies and current taxonomy. Our findings support the monophyly of each genus within the subfamily Aemodogryllinae, with a minor inconsistency between taxonomy and phylogeny resolved by resurrection of the genus Gymnaeta Adelung. Fossil-calibrated molecular clock analysis used 11,124 bp alignment of 13 complete mitochondrial protein-coding genes for 20 species of Rhaphidophoridae, with a focus on the neglected Rhaphidophorinae and Aemodogryllinae lineages. Divergence time estimates suggest that the most recent common ancestor of the family lived during the Early Jurassic (189 Mya ± 23 Mya) before Pangea broke into the supercontinents or possibly during the early stage of breakup when Gondwana and Laurasia were still connected by land. The two subfamilies, Rhaphidophorinae and Aemodogryllinae, that overlap in Asia are estimated to have diverged 138 Mya ± 17 Mya, well before the Late Cretaceous northern connection between America and Asia (the Bering Land Bridge). Thus, our extended sampling of species from East Asia and Oceania refutes the importance of continental drift in the evolution of this wingless orthopteran family. Full article

The Davie Fracture Zone (Davie FZ)—among the longest offshore transform systems in East Africa—mediated Madagascar’s southward displacement following Gondwana’s Early Jurassic breakup. This giant structure has a distinct topography and gravity field signals. However, it is buried by thick sediments in its northern segment offshore Tanzania, hindering understanding of the internal structures and their origin. In this study, we applied 2-D multichannel seismic to analyze the structural characteristics and evolution of the Davie FZ. The Davie FZ is located in the oceanic domain, which is bordered by the landwards-dipping overthrust fault at the continent–ocean boundary. Volcano sediments atop the basement with undulating Moho reflection below depict a typical oceanic domain. Distinct compressive deformation characterized by the crustal undulation of around 40 km wavelength forms folded oceanic crust, and Late Jurassic sediments onlap onto the crest of the folded basement. The Davie FZ is localized in a corridor with the thickened oceanic crust and is presented by positive flower structures with faulted uplifted basement and deepened Moho. The Davie FZ evolved from a proto-transform fault located in Gondwana before the spreading of the West Somali Basin. During the Late Jurassic, a kinematic change shifted the spreading direction from NW–SE to N–S, resulting in a strike-slip of the Davie FZ and contemporaneous transpressional deformation offshore Tanzania. The Davie FZ is an excellent case to understand the tectonic-magmatic process forming this transform margin. Full article

The Sichuan Basin is a key area for shale gas energy exploration in China. However, the pore evolution mechanism and accumulation effect of the Lower Jurassic continental shale gas in the northeastern Sichuan Basin remain poorly understood. In this study, the pore structure characteristics of shale reservoirs and the dynamic accumulation and evolution of shale gas in the northern Fuling and Yuanba areas were systematically analyzed by adsorption experiments, high-pressure mercury injection joint measurement, and thermal simulation experiments. The results indicate the following: (1) The continental shale in the study area is predominantly composed of mesopores (10–50 nm), which account for approximately 55.21% of the total pore volume, followed by macropores (5–50 μm) contributing around 35.15%. Micropores exhibit the lowest proportion, typically less than 10%. Soluble minerals such as clay minerals and calcite significantly promote pore development, while soluble organic matter may block small pores during hydrocarbon generation, which facilitates the enrichment of free gas. (2) The thermal simulation experiment reveals that pore evolution can be divided into two distinct stages. Prior to 450 °C, hydrocarbon generation leads to a reduction in pore volume due to the compaction and transformation of organic matter. After 450 °C, organic matter undergoes cracking processes accompanied by the formation of shrinkage fractures, resulting in the development of new macropores and a significant increase in pore volume. This indicates that thermal energy input during the thermal evolution stage plays a key role in reservoir reconstruction. (3) The early Jurassic sedimentary environment controls the enrichment of organic matter, and the Cretaceous is the key period of hydrocarbon accumulation. Hydrocarbon generation and diagenesis synergistically promote the formation of gas reservoirs. The Cenozoic tectonic activity adjusted the distribution of gas reservoirs, and finally formed the enrichment model with the core of source–reservoir–preservation dynamic matching. For the first time, combined with dynamic thermal simulation experiments, this study clarifies the stage characteristics of pore evolution of continental shale and identifies the main controlling factors of shale gas accumulation in the Lower Jurassic in northeastern Sichuan, which provides a theoretical basis for continental shale gas exploration and energy resource development, offering important guidance for optimizing the selection of exploration target areas. Full article

Continental rifting is the process by which land masses separate and create new ocean basins. The emplacement of large igneous provinces (LIPs) is thought to have played a key role in (super) continental rifting; however, this relationship remains controversial due to the lack of a clearly established mechanism linking LIP emplacement to continental fragmentation. Here, we show that plume flow links LIP magmatism to continental rifting quantitatively. Our findings are further supported by the sedimentary record, as well as by the mineralogy and petrology of the rocks. This study analyzes the early Cretaceous separation of West Gondwana into South America and Africa. Prior to rifting, Jurassic hiatuses in the stratigraphic record of continental sediments from both continents indicate plume ascent and the resulting dynamic topography. Cretaceous mafic dyke swarms and sill intrusions are products of major magmatic events that coincided with continental rifting, leading to the formation of large igneous provinces in South America and Africa, including the Central Atlantic Magmatic Province, Equatorial Magmatic Province, Paraná–Etendeka, and Karoo. It has been suggested that dyke intrusions may weaken the lithosphere by reducing its mechanical strength, creating structural weaknesses that localize extensional deformation and facilitate rift initiation. The sedimentary analysis and petrological evidence from flood basalt magmas indicate that plumes may have migrated from the depths toward the surface during the Jurassic and erupted during the Cretaceous. It is thought that the resulting fast plume flow, induced by one or more mantle plumes, generated a dynamic force that, in combination with lithospheric weakening from dyke intrusion, eventually rifted the lithosphere of West Gondwana. Full article

The Dehbid region, located in the southern part of the Sanandaj–Sirjan Zone (SSZ), is a significant iron oxide mining district with over 20 iron oxide deposits (IODs) and reserves of up to 50 million tons of iron oxide ores. The region features a NW–SE oriented ductile shear zone, parallel to the Zagros thrust zone, experienced significant deformation. Detailed structural studies indicate that the iron mineralization is primarily stratiform to stratabound and hosted in late Triassic to early Jurassic silicified dolomites and schists. These ore deposits consist of lenticular iron oxide orebodies and exhibit various structures and textures, including banded, laminated, folded, disseminated, and massive forms of magnetite and hematite. The Fe₂O₃ content in the mineralized layers varies from 30 to 91 wt%, whereas MnO has an average of 3.9 wt%. The trace elements are generally low, except for elevated concentrations of Cu (up to 4350 ppm) and Zn (up to 3270 ppm). Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis of magnetite reveals high concentrations of Mg, Al, Si, Mn, Ti, Cu, and Zn, with significant depletion of elements such as Ga, Ge, As, and Nb. This study refutes the hypothesis of vein-like or hydrothermal genesis, providing evidence for a sedimentary origin based on the trace element geochemistry of magnetite and LA-ICP-MS geochemical data. The Dehbid banded iron ores (BIOs) are thought to have formed under geodynamic conditions similar to those of BIOs in back-arc tectonic settings. The combination of anoxic conditions, submarine hydrothermal iron fluxes, and redox fluctuations is essential for the formation of these deposits, suggesting that similar iron–manganese deposits can form during the Phanerozoic under specific geodynamic and oceanographic conditions, particularly in tectonically active back-arc environments. Full article

A combination of microstructural, fluid inclusion, and in situ sulfur isotopic analyses of pyrite, along with major and trace element studies of the mineralization-hosting sandstone, reveals the complexity of its genesis from the Jurassic Toutunhe Formation in the Liuhuanggou sandstone-hosted uranium deposit, Southern Junggar Basin. Based on field geological investigations and the geochemical characteristics, it is concluded that the source of the ore-bearing sandstones originates from felsic igneous rocks in the Northern Tianshan and Central Tianshan regions. Through optical microscopy and scanning electron microscopy (SEM), three generations of pyrite were identified: framboidal pyrite, concentric overgrown pyrite, and sub-idiomorphic to idiomorphic cement pyrite. The sulfur isotopes of the pyrite were analyzed using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The results indicate that each type of pyrite has distinct sulfur isotope compositions (the framboidal pyrite: −16.85‰ to +2.16‰, the concentric overgrown pyrite: −7.86‰ to +10.32‰, the sub-idiomorphic to idiomorphic cement pyrite: +9.16‰ to +16.77‰). The framboidal pyrite and the sub-idiomorphic to idiomorphic cement pyrite were formed through bacterial sulfate reduction (BSR), while the concentric overgrown pyrite was formed through thermochemical sulfate reduction (TSR) triggered by the upward migration of hydrocarbons. The discovery of hydrocarbon inclusions provides evidence for the involvement of deep-seated reducing fluids in uranium mineralization. Uranium mineralization occurred in two distinct stages: (1) The early stage involved the interaction of uranium-bearing fluids with reductants in the mineralization-hosting strata under the influence of groundwater dynamics, leading to initial uranium enrichment. (2) The later stage involved the upward migration of deep-seated hydrocarbons along faults, which enhanced the reducing capacity of the sandstone and resulted in further uranium enrichment and mineralization. Full article