Next Article in Journal
Implementation of Solvometallurgical Processing in the Recovery of Valuable Metals from a Sulfide Ore
Previous Article in Journal
Advances in Lithium Extraction from Spodumene: Alternatives to Sulfuric Acid Digestion
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 15
Issue 6
10.3390/min15060575
minerals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Constraints from Geochemistry of Mineralization-Hosting Sandstone and Sulfur Isotopes of Pyrite on Uranium Mineralization in the Liuhuanggou Area, Southern Junggar Basin

by
Junyang Li
1,
Yu Zhou
1,*,
Chunji Xue
2,
Shizhong Chen
1,
Guoxiong Ma
3,
Zuohuai Yang
1,
Min Liu
1,
Le Yang
4 and
Jie Gong
5
1
Urumqi Comprehensive Survey Center on Natural Resources, China Geological Survey, Innovation Base of Metallogenic Prediction and Prospecting in Central Asia Orogenic Belt, Urumqi 830057, China
2
State Key Laboratory of Geological Processes and Mineral Resources, School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
3
Xinjiang Research Center for Mineral Resources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
4
School of Geology and Mining Engineering, Xinjiang University, Urumqi 830017, China
5
Xinjiang Branch of China National Logging Corporation, Karamay 834000, China
*
Author to whom correspondence should be addressed.
Minerals 2025, 15(6), 575; https://doi.org/10.3390/min15060575
Submission received: 30 March 2025 / Revised: 13 May 2025 / Accepted: 18 May 2025 / Published: 28 May 2025
(This article belongs to the Section Mineral Geochemistry and Geochronology)
Browse Figures
Versions Notes

Abstract

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.

1. Introduction

The Sandstone-hosted U deposits characterized by shallow burial, great reserves, and low exploitation cost because of in situ techniques has become the most important type of U resources in recent years, accounting for more than 30% of the world annual production [1,2,3,4,5]. While sandstone-hosted U deposits have a global occurrence, the latitudinal belt spanning 20° N to 50° N in the Northern Hemisphere accounts for a disproportionately large share of both known occurrences and estimated global reserves. Particularly noteworthy is the Central Asian Metallogenic Belt, which demonstrates an exceptional concentration of these deposits. (Figure 1). The U mineralization of sandstone-hosted deposits generally occurs in permeable sandstones (predominantly arkosic) that are bounded by and interbedded with less permeable sediments (e.g., coal seams and mudstones) under low-temperature conditions [6,7]. Uranium commonly precipitates as tetravalent U phases at redox interfaces attributed to U (VI) reduction by a variety of reducing media, including organic material, sulfides, and possibly intercalated ferro-magnesian minerals [2,8,9,10,11,12,13].
The main issue about the origin of these deposits is the source of the uranium and its reductants. Some argue that intrinsic carbonaceous debris and sulfide minerals within sandstone reservoirs are the only essential reductants (Model 1), such as the deposits in the Wyoming Basin, USA [7] and the Erlian Basin, China [6]. Others contend that uranium reduction is not easily independently accomplished inside hosting sandstones, and they propose that extrinsic hydrocarbon-bearing (CH4 and H2S) hydrothermal fluids, migrated from deep petroleum systems or coal seams, interact with U-bearing oxygenated fluids, resulting in the precipitation of uranium minerals (Model 2), for instance, in the Texas Coastal Plain of the United States [14]. Then, there is a combination of the above two models (Model 3), marked by an established deposit (Model 1) being re-reduced by extrinsic hydrocarbons, such as the Northern Ordos Basin, China [4]. Whilst substantial evidence supports the involvement of endogenous reduced phases in uranium mineralization, the potential contribution of exogenous hydrocarbon-bearing hydrothermal fluids sourced from hydrocarbon-rich strata to ore-forming processes remains controversial.
The Junggar Basin, as the second largest sedimentary basin in China, is adjacent to a world-renowned concentration of U deposits in the area of the Central Asian Metallogenetic Belt [15]. Large sandstone-hosted U deposits have been discovered in the Turpan-Hami and Yili Basins, which share a similar structural evolution and sedimentary rock associations. However, no major uranium deposits have been found in the Junggar Basin to date.
Pyrite is a common accessory mineral in sandstone-hosted U deposits, and it can be formed during sedimentation or mineralization through interactions between microbial sulfate reduction or oxidizing fluids and reducing substances [1,16,17]. When environmental conditions change, such as pH, Eh, and the concentrations of Fe2+ and S2−, the composition and structure of pyrite will also change. Therefore, the sulfur isotopes of pyrite can constrain the source and role of reductants in the uranium metallogenic system [18,19,20,21,22].
This paper focuses on pyrite in the mineralization-hosting sandstone of the Toutunhe Formation (J2t) in the Liuhuanggou area. This was accomplished by field geological surveys, drill core logging, and petrographic identification; whole-rock major and trace element analyses and in situ sulfur isotope analyses were performed on the mineralization-hosting sandstone and pyrite. The metallogenic process of the deposit is preliminarily discussed, aiming to provide a basis for a deeper understanding of the metallogenesis of the deposit and to provide theoretical support for sandstone-hosted U deposit exploration in the Junggar Basin.
Minerals 15 00575 g001
Figure 1. Mercator projection map with the world distribution of sandstone-hosted U deposits divided into four subtypes (modified from [23]).
Figure 1. Mercator projection map with the world distribution of sandstone-hosted U deposits divided into four subtypes (modified from [23]).
Minerals 15 00575 g001

2. Geological Setting

2.1. Regional Geology

The Junggar Basin is located in the northern part of the Xinjiang Uygur Autonomous Region, and its tectonic setting lies at the convergence of the Kazakhstan Plate, Siberian Paleoplate, and Tarim Paleoplate (Figure 2a). The main body of the basin belongs to the Kazakhstan–Junggar Paleoplate. It is a large superimposed sedimentary basin that developed from the Late Carboniferous to the Quaternary, surrounded on three sides by Paleozoic suture zones [24]. The basin has a complete stratigraphic sequence (Figure 2b). The basin’s basement is generally considered to be a two-layered continental crust composed of a Precambrian crystalline basement with an overlying folded Hercynian complex [25]. The basement mobile belt has undergone multiple stages of folding, magmatism, and metasomatism, with the development of various granites and intermediate–acidic volcanic rocks. The Upper Carboniferous and Permian systems are characterized by continental effusive facies sediments. Current studies suggest that the paleocontinental basement architecture favors uranium mineralization within the basin [26].
The southern margin of the Junggar Basin is located at the junction of the Junggar Basin and the North Tianshan Mountains. It is a long-term developing, multi-stage superimposed inherited structural belt, extending from Usu in the west to Urumqi in the east, bordering the Eren Habirga Mountains in the south and reaching the central depression in the basin’s interior in the north. It consists of five second-order structural units: the Sikeshu Depression, the Qigu Fault–Fold Belt, the Huomatu Anticline Belt, the Huan Anticline Belt, and the Fukang Fault Zone [27].
Minerals 15 00575 g002
Figure 2. (a) Tectonic location map of the southern margin of the Junggar Basin; (b) simplified geological map of the southern margin of the Junggar Basin (modified from [28]). 1. Quaternary System; 2. Neogene System; 3. Paleogene System; 4. Cretaceous System; 5. Upper Jurassic System; 6. Middle-Lower Jurassic System; 7. Triassic System; 8. Permian System; 9. Carboniferous System; 10. Devonian System; 11. Granitic Intrusive Rocks; 12. Mid-Hercynian Gabbro; 13. Fault; 14. Uranium Mineralization Occurrence; 15. City. The black box in Figure 2a delineates the approximate location of the area magnified in Figure 2b, whereas the corresponding black box in Figure 2b identifies the region further detailed in Figure 3b.
Figure 2. (a) Tectonic location map of the southern margin of the Junggar Basin; (b) simplified geological map of the southern margin of the Junggar Basin (modified from [28]). 1. Quaternary System; 2. Neogene System; 3. Paleogene System; 4. Cretaceous System; 5. Upper Jurassic System; 6. Middle-Lower Jurassic System; 7. Triassic System; 8. Permian System; 9. Carboniferous System; 10. Devonian System; 11. Granitic Intrusive Rocks; 12. Mid-Hercynian Gabbro; 13. Fault; 14. Uranium Mineralization Occurrence; 15. City. The black box in Figure 2a delineates the approximate location of the area magnified in Figure 2b, whereas the corresponding black box in Figure 2b identifies the region further detailed in Figure 3b.
Minerals 15 00575 g002

2.2. Deposit Geology

The Liuhuanggou area, where the study area is located, is situated within the first row of anticlinal structures of the Qigu Fault–Fold Belt in the piedmont thrust zone of the North Tianshan Mountains, located between the Akedeke Syncline and the Liuhuanggou Anticline. In this area, the sandstone-hosted U deposits of the Toutunhe Formation are mainly developed in the two limbs of the three rows of structurally broad and gentle anticlines [29] (Figure 3a). The Mesozoic–Cenozoic strata in the Liuhuanggou area are relatively complete and thick (Figure 3b). The Jurassic system (J) consists of a thick sequence of fluvial–lacustrine clastic rocks, exhibiting an angular unconformity with the underlying Triassic system. The strata are well developed and represent the most important mineralization-hosting sequence in the area. From bottom to top, they are the Badaowan Formation (J1b), the Sangonghe Formation (J1s), the Xishanyao Formation (J2x), the Toutunhe Formation (J2t), the Qigu Formation (J3q), and the Kalaza Formation (J3k) (Figure 4): The Badaowan Formation (J1b) is mainly composed of fluvial–lacustrine and swamp facies deposits, containing coal seams or coal streaks. The Sangonghe Formation (J1s) is a set of fluvial–lacustrine gray and grayish-green sandstone, siltstone, and mudstone deposits, with fluvial delta deposits in the marginal areas. The Xishanyao Formation (J2x) is mainly a lacustrine delta system deposit, usually containing two coal seams, with a maximum thickness of 90 m, generally 5–30 m. The Toutunhe Formation (J2t), which is relatively complete in this area and serves as the main uranium-bearing horizon, comprises carbonaceous fluvial–lacustrine variegated, gray, and grayish-green mudstone, sandstone, and conglomerate interbedded with purplish-red mudstone, sandstone, and conglomerate. It contains coal streaks and exhibits an unconformable contact with the underlying strata. The Qigu Formation (J3q) consists of dark red to purplish-red mudstone and sandstone interbedded with tuffaceous sandstone and tuff. The Kalaza Formation (J3k) is characterized by thick sequences of brownish-red piedmont facies and fan-delta facies muddy and sandy conglomerate [30,31].
Minerals 15 00575 g003
Figure 3. (a) Geotectonic location map of the Liuhuanggou area, southern margin of the Junggar Basin; (b) simplified geological map of the Liuhuanggou area, southern margin of the Junggar Basin (modified from [32]). 1. Quaternary System; 2. Dushanzi Formation; 3. Shawan Formation; 4. Anjihaihe Formation; 5. Ziniquanzi and Donggou Formations; 6. Lianmuqin and Shengjinkou Formations; 7. Hutubihe and Qingshuihe Formations; 8. Kalaza Formation; 9. Qigu Formation; 10. Toutunhe Formation; 11. Xishanyao Formation; 12. Sangonghe Formation; 13. Badaowan Formation; 14. Xiaoquangou Group; 15. Stratigraphic Boundary; 16. Angular Unconformity Contact; 17. Observed Fault; 18. Inferred Fault; 19. Observed Strike-Slip Fault; 20. Inferred Strike-Slip Fault; 21. Reverse Fault; 22. Study Area; 23. Uranium Mineralization Occurrence; 24. Sampling and Drilling Locations. The red box in Figure 3a indicates the approximate location of the area depicted in Figure 3b, while the black box in Figure 3b marks the general position corresponding to Figure 11.
Figure 3. (a) Geotectonic location map of the Liuhuanggou area, southern margin of the Junggar Basin; (b) simplified geological map of the Liuhuanggou area, southern margin of the Junggar Basin (modified from [32]). 1. Quaternary System; 2. Dushanzi Formation; 3. Shawan Formation; 4. Anjihaihe Formation; 5. Ziniquanzi and Donggou Formations; 6. Lianmuqin and Shengjinkou Formations; 7. Hutubihe and Qingshuihe Formations; 8. Kalaza Formation; 9. Qigu Formation; 10. Toutunhe Formation; 11. Xishanyao Formation; 12. Sangonghe Formation; 13. Badaowan Formation; 14. Xiaoquangou Group; 15. Stratigraphic Boundary; 16. Angular Unconformity Contact; 17. Observed Fault; 18. Inferred Fault; 19. Observed Strike-Slip Fault; 20. Inferred Strike-Slip Fault; 21. Reverse Fault; 22. Study Area; 23. Uranium Mineralization Occurrence; 24. Sampling and Drilling Locations. The red box in Figure 3a indicates the approximate location of the area depicted in Figure 3b, while the black box in Figure 3b marks the general position corresponding to Figure 11.
Minerals 15 00575 g003
Minerals 15 00575 g004
Figure 4. Stratigraphic section of the Jurassic system in the Liuhuanggou area, southern margin of the Junggar Basin (modified from [33]). Fm = Formation.
Figure 4. Stratigraphic section of the Jurassic system in the Liuhuanggou area, southern margin of the Junggar Basin (modified from [33]). Fm = Formation.
Minerals 15 00575 g004
The mineralization-hosting rock at the bottom of the Toutunhe Formation in the Liuhuanggou area is gray, gravel-bearing, medium- to coarse-grained lithic feldspathic sandstone (Figure 5). The rock is mainly composed of gravel-sized clasts (10%–15%), sand-sized clasts (75%–85%), matrix (2%–7%), and a small amount of opaque minerals (5%–10%). The gravel-sized clasts are mainly fine-grained lithic sandstone, medium- to coarse-grained quartz sandstone, ferruginous siltstone, and monocrystalline K-feldspar and plagioclase, generally subangular to subrounded, with a size of 2–5 mm, and are distributed sporadically. The sand-sized clasts are feldspar, quartz, and lithic fragments, generally subangular to subrounded, with a size of 0.5–1 mm, and are randomly distributed. The feldspars include plagioclase and K-feldspar, while the quartz is predominantly monocrystalline with unaltered surfaces. The lithic fragments include rhyolite, siliceous rock, andesite, metamorphic argillaceous siltstone, and quartzite, with mica flakes also visible. The interstitial materials are clay matrix and calcareous cement. The opaque minerals are predominantly granular-shaped, black-opaque, and distributed as heterogeneous aggregates.
Scanning electron microscopy–energy-dispersive spectroscopy analysis shows that the sandstone cement in the uranium ore contains a large amount of uranium minerals, which mostly occur as coatings around detrital grains (Figure 6a,b). The uranium minerals include uraninite; unknown uranium minerals containing U, Si, P, Y, and other elements; and brannerite. The pitchblende exhibits colloidal, spherulitic, reniform, botryoidal, and submicroscopic morphologies, with particle sizes predominantly ranging from 2 to 10 μm. In backscattered electron (BSE) images, it displays a heterogeneous brightness, suggesting potential post-depositional alteration. It is primarily distributed within clay minerals and pyrite, showing a close association with the three generations of pyrite (Figure 6c,d). Unidentified uranium minerals containing U, Si, P, and Y occur as irregular aggregates, mostly adjacent to pitchblende (Figure 6c,d). The brannerite predominantly displays radial and irregular morphologies, embedded within clay minerals.

3. Analytical Methods

The samples for this study were all collected from drill core from the Liuhuanggou area, from within the gray, gravel-bearing, medium- to coarse-grained lithic feldspathic sandstone of the lower sub-section of the lower Toutunhe Formation. The rock contains abundant carbonaceous detritus and pyrite grains. The samples were collected during drilling and were relatively fresh.

3.1. Scanning Electron Microscope

The energy-dispersive spectroscopy analysis under scanning electron microscopy was performed at the Rock and Mineral Laboratory of the Institute of Geology and Mineral Resources, Beijing Research Institute of Uranium Geology (Beijing, China). The analysis was conducted using a TESCAN VEGA3 (Waltham, MA, USA) tungsten filament scanning electron microscope equipped with an EDAX (Kyoto, Japan) Element energy-dispersive spectrometer. The instrument specifications include a backscattered electron image resolution of 3.5 nm (at 30 kV) and EDAX spectrometer energy resolution of 126 eV. The operational parameters were set at 20 kV accelerating voltage, 15 μA beam current, and 15 mm working distance. The EDS system exhibited a dead time of 30%–40%, with a spectral acquisition time exceeding 30 s.

3.2. Whole-Rock Major and Trace Element Analysis

Whole-rock major element analysis was performed at the Testing Center of the Xinjiang Uygur Autonomous Region Nonferrous Geological Exploration Bureau (Urumq, China). After removing the edges and oxidized parts of the samples, the samples were first crushed into small pieces, then ground into powder finer than 200 mesh, and finally subjected to whole-rock major and trace element testing. Major and trace elements were analyzed using a Thermo Fisher ARL Perform’X 4200 X-ray fluorescence spectrometer and a Perkin-Elmer Sciex ELAN DRCe ICP-MS analyzer manufactured by the Shimadzu Corporation (Kyoto, Japan). The analytical precision was better than 1% and 10%, respectively. Specific experimental steps can be found in [34].

3.3. In Situ Sulfur Isotope Analysis of Pyrite

In situ sulfur isotope analysis was performed at Guangzhou Tuoyan Testing Technology Co., Ltd (Guangzhou, China). Samples were collected from industrial boreholes in the Liuhuanggou area, and samples from different mineralization stages were cut into probe slices. Representative samples of the types of pyrite from each stage were selected for experimental testing. A micro-area in situ S isotope analysis of sulfides was performed using laser ablation–multi-collector inductively coupled plasma mass spectrometry (Omaha, NE, USA; Wrexham, Wales, UK). The laser ablation system was a New Wave Research 193 nm ArF excimer laser ablation system. The laser energy density (fluence) used for S isotope testing was 3.5 J/cm2, the frequency was 3 Hz, the ablation spot size was 25–37 μm, the ablation method was single-point ablation, the carrier gas was high-purity helium (700 mL/min), and the auxiliary gas was Ar, generally 0.96 L/min. S isotope analysis was performed using a Thermo Scientific (Omaha, NE, USA; Wrexham, Wales, UK). multi-collector inductively coupled plasma mass spectrometer Neptune Plus. The Neptune Plus has 8 movable Faraday cups and 1 fixed central cup. Faraday cups L3, C, and H3 receive 34S, 33S, and 32S, respectively. The data acquisition mode was TRA mode, the integration time was 0.131 s, the background acquisition time was 15 s, the sample integration time was 40 s, and the purge time was 70 s. Other instrument parameters were set as follows: RF power: 1300 W; nebulizer gas Neb: 0.96 mL/min. Other detailed analytical methods can be found in [35,36].

3.4. Microspectrofluorometric Analysis of Fluid Inclusions

The microspectrofluorometric analysis of fluid inclusions was conducted at the Key Laboratory of Tectonics and Petroleum Resources (Ministry of Education), China University of Geosciences (Wuhan, China). The analysis was performed using a LEICA TCS SPE (Wetzlar, Germany) confocal microscope system. This system employs prism-based spectral dispersion, demonstrating a significantly higher light transmission efficiency compared to grating-based systems. Equipped with a spectral detection system, it allows wavelength selection across the 430–750 nm range, making it suitable for the detection and spectral scanning of any fluorescent dyes and autofluorescence. The instrument exhibits a high detection sensitivity.

4. Results

4.1. Major Elements

The SiO2 content of the uranium-bearing sandstone in the Liuhuanggou area varies widely (72.56%–80.03%), with an average of 77.04% (Table 1). As the SiO2 content increases, the content of K2O (2.83%–3.18%) and Al2O3 (10.27%–11.89%) also gradually increases, showing a positive correlation. The content of CaO (0.54%–6.99%), MnO (0.02%–0.14%), Na2O (2.19%–2.97%), and TFe2O3 (1.37%–2.36%) gradually decreases, showing a negative correlation. The content of other oxides such as TiO2 (0.20%–0.73%), MgO (0.02%–0.14%), and P2O5 (0.05%–0.07%) shows no significant correlation with the SiO2 content. The Chemical Index of Alteration (CIA) for these sandstones, calculated as 100 × [Al2O3/(Al2O3 + CaO* + Na2O + K2O)], yields values between 33.33 and 58.47 (mean 50.21). These relatively low CIA values suggest that the sandstones experienced only weak chemical weathering processes [37].

4.2. Trace Elements

As shown in Table 2, the total rare earth element (ΣREE) content of the uranium-bearing sandstone is 72.04 × 10−6–162.09 × 10−6, the light rare earth element (LREE) content is 64.22 × 10−6–149.33 × 10−6, and the heavy rare earth element (HREE) content is 10.39 × 10−6–17.41 × 10−6 (Table 2). Due to their similar chemical properties, rare earth elements are basically undifferentiated during diagenesis and metamorphism, and their distribution patterns are still similar to those of the source rocks, so they can be used to trace the provenance of sediments [38]. Chondrite-normalized rare earth element distribution curves show that the rare earth element distribution patterns of the uranium-bearing sandstone are generally consistent, enriched in light rare earth elements (LREEs) and depleted in heavy rare earth elements (HREEs), with LREE/HREE ratios of 6.18–8.75 (average 7.95) (Figure 7a). The δEu values of the samples are all less than 1 (0.72–0.90), the δCe values are all close to 1 (1.01–1.05), and there is a significant Eu negative anomaly, which suggests that the entire mineralization-hosting rock has a unified provenance, sedimentary environment, and tectonic background. Primitive mantle-normalized spider diagrams show that the overall distribution characteristics of the uranium-bearing sandstone are basically the same, with obvious positive anomalies of U, Ba, Nb, Zr, and Zn, and negative anomalies of Pb, Mo, Eu, Sr, and Ni (Figure 7b). The U content varies widely (2.27 × 10−6–79.5 × 10−6) (Table 3), with an average of 17.16 × 10−6. The Th content is 3.72 × 10−6–9.58 × 10−6, and the Th/U ratio is 0.1~2.61.

4.3. Pyrite Micromorphologies

The mineralization-stage pyrite morphologies display the following sequence of crystallization: (i) framboidal pyrite, (ii) concentric overgrown pyrite, and (iii) sub-idiomorphic to idiomorphic cement pyrite (Figure 8). Framboids are composed of densely packed, spherical aggregates of submicrometer-sized pyrite crystals, forming clusters of up to hundreds of individual framboids. Discrete framboids are commonly observed in a range of size varying from 5 to 30 μm in diameter (Figure 8a,b). The framboidal pyrite is predominantly distributed within the matrix, exhibiting a close spatial and genetic association with both clay minerals and organic matter. Significantly, in most cases the microcrystals show a disordered distribution, with the precipitation of U minerals in the interstices between them (Figure 8a,b). The concentric overgrown pyrite radially extends from 10 to 60 μm. Individual concentric overgrown pyrite grains tend to join each other, evolving into larger bands that form larger zones cementing the framboid clusters (Figure 8a,b). Sub-idiomorphic to idiomorphic cement pyrite presenting as homogeneous textures is the most abundant morphology of pyrite in sandstone-hosted U deposits, and it has the effect of cementing clastic particles, thus reducing the porosity of sandstones. The framboids and the concentric overgrowth were both cemented by a final stage of sub-idiomorphic to idiomorphic pyrite (Figure 8c,d).

4.4. Sulfur Isotopes

The sulfur isotopic composition of the pyrite is shown in Table 4. The δ34S values of the three stages of pyrite range from −16.85 to +16.77‰ (n = 35). The δ34S values progressively increase across successive pyrite generations (Figure 9): (i) Framboidal pyrite has strongly negative δ34S values, ranging from −16.85 to −2.16‰ (average −7.41‰). (ii) Concentric overgrown pyrite has intermediate δ34S values, ranging from −7.86 to 10.32‰ (average −0.2‰). (iii) Sub-idiomorphic to idiomorphic cement pyrite has relatively positive δ34S values, ranging from 9.16 to 16.77‰ (average 14.04‰) (Figure 9).

4.5. Microspectrofluorometric Analysis of Fluid Inclusions

The results are shown in Figure 10. Fluorescence microscopy is widely used to identify hydrocarbon inclusions, as hydrocarbons fluoresce under ultraviolet (UV) light excitation. In this study, the samples emitted a blue fluorescence under UV light, indicating the presence of light hydrocarbons within the inclusions. The fluorescence color correlates with hydrocarbon composition and maturity, where blue typically corresponds to a lower maturity or lighter hydrocarbon components. A maximum fluorescence emission wavelength of 495 nm further confirms the dominance of light hydrocarbons.

5. Discussion

5.1. Provenance Terrains of Mineralized Sandstone

In sandstone-hosted U deposits, studying the thickness and distribution characteristics of sand bodies is of great significance for determining the source of materials and understanding fluid migration processes. In terms of sand bodies’ thickness, J2t1-1 has the greatest thickness compared to other lower sub-units, indicating that the sand bodies in the study area are primarily hosted in the lower sub-section of the Lower Member of the Toutunhe Formation (Figure 4). Regarding sand bodies’ distribution, the thickest sand bodies are located in the northwest and western parts of the study area (Figure 11), with a northeastward thickening trend. Based on the analysis of existing drilling data on uranium mineralization, it is concluded that, in the vertical stratigraphic sequence, uranium mineralization is mainly distributed within J2t1-1, occurring as two thinner layers. In terms of spatial distribution, uranium mineralization extends along the NWW direction, indicating that the southwestern erosion source area provided the primary source of material for the study area. This conclusion corroborates earlier research [40], which, through detrital zircon U-Pb geochronology and Hf isotope analysis, suggested that the detrital materials were primarily derived from the Northern Tianshan Orogenic Belt and the Central Tianshan Orogenic Belt. In the discrimination function diagram for sandstone’s provenance (Figure 12), the uranium-bearing sandstone samples are all located within the provenance field of felsic igneous rocks. Based on the findings above and existing research results, it is inferred that the felsic igneous rocks in the Northern Tianshan and Central Tianshan regions may serve as the provenance area for the uranium-bearing sandstones of the Toutunhe Formation.

5.2. Sulfur Sources and Pyrite Genesis

The depletion or enrichment of sulfur isotopes reveals information about geochemical processes, hydrothermal origins, and sedimentary diagenesis [42]. The δ34S values of pyrite in most sandstone-hosted U deposits worldwide exhibit a wide range, varying from −72‰ to +142.8‰ (Figure 13). In the uranium-bearing sandstones of the Liuhuanggou area, the δ34S values of pyrite are relatively dispersed, indicating that the formation of pyrite involved at least two sulfur sources. The isotopic ratios of the framboidal pyrite display discrete characteristics, with most δ34S values showing depletion, ranging from −16.85‰ to 2.16‰, with an average of −7.41‰. Such low δ34S values are characteristic of biological sulfur sources [43,44]. The sulfur in the framboidal pyrite may originate from the dissolution of sulfate minerals in overlying strata during the infiltration of oxidized atmospheric precipitation. During bacterial sulfate reduction, sulfate-reducing bacteria primarily utilize energy provided by organic matter and preferentially break the weaker 32S-O bonds, resulting in sulfides enriched in lighter isotopes [45,46,47,48]. Consequently, the δ34S values of the resulting sulfides are significantly lower than those of the original sulfate. Clay minerals, with their large specific surface area and surface charges, can adsorb organic matter from the surrounding environment onto their surfaces or interlayers through physical or chemical adsorption. Under the microscope, the framboidal pyrite is often observed to coexist with clay minerals (Figure 6c,d).
Unlike the aforementioned biogenic pyrite, the δ34S values of the concentric overgrown pyrite are concentrated within the range of −7.86‰ to +10.32‰, indicating that its formation mechanism differs from bacterial sulfate reduction. The δ34S values are similar to those of magmatic pyrite [74], but they may also correspond to the fractionation effects of thermochemical sulfate reduction [75] or a binary mixture between TSR and BSR [76]. Therefore, it is necessary to further investigate the genesis of concentric overgrown pyrite in conjunction with the geological background of the study area, which is of great significance for understanding the ore-forming fluids of the Liuhuanggou uranium deposit.
Based on drilling and field outcrop observations in the Liuhuanggou area, no evidence of magmatic fluid activity has been found. Moreover, the relatively stable structural characteristics of the Junggar Basin are conducive to sedimentation and the formation of various energy resources. Therefore, the pyrite from various stages is unlikely to be of magmatic origin. BSR typically occurs at temperatures below 60 °C to 80 °C [77,78]. Above this range, the metabolic activity of most sulfate-reducing bacteria ceases. In contrast, TSR generally takes place when burial temperatures reach approximately 100–140 °C [79]. Since the Late Jurassic, the southern margin of the Junggar Basin has undergone a prolonged uplift, leading to the reduced burial depths of sediments and a decrease in geothermal gradients. Concentric overgrown pyrite does not appear to be generated by TSR processes. However, due to the long-term uplift of strata, the dissipation of hydrocarbons in the study area may have occurred. In the northern part of the study area lies the Hutubi gas field. According to research by Chen Lei et al., its formation is attributed to hydrocarbons from the southern or deeper source rocks of the Badaowan, Sangonghe, and Xishanyao formations migrating to shallower northern strata due to tectonic movements [15]. The study area as a whole is located within the Qigu Fold–Thrust Belt of the Junggar Basin, specifically in the first row of anticlines near the core of the three-row anticlinal zone. This position is favorable for the accumulation of hydrocarbons and other reducing substances. Field investigations revealed that although the lower strata of the Toutunhe Formation are predominantly gray-green and gray, a significant amount of white and gray-white sandstone was observed. These distinctly reduced “bleached sandstones” suggest strong hydrocarbon dissipation in the study area. During drilling operations, substantial amounts of bitumen were observed in the sandstone of the Toutunhe Formation. Evidence from oil inclusion in the uranium-bearing sandstone of the Toutunhe Formation further indicates the presence of hydrocarbon emplacement on a certain scale (Figure 14). The upward migration of hydrocarbon-rich fluids, accompanied by deep high-temperature fluids (the average homogenization temperature of the inclusions is 168 °C, unpublished data), may have triggered TSR reactions. Therefore, the moderate δ34S values of concentric overgrown pyrite (−7.86‰ to +10.32‰) are likely caused by TSR processes induced by the heat carried by the upward migration of deep hydrocarbon-rich fluids. The ascending hydrocarbons provide hydrocarbon reductants that facilitate sulfate reduction, enhancing the efficiency of uranium reduction and precipitation, thereby forming uranium–pyrite coexisting assemblages. This phenomenon aligns with microscopic observations showing concentric overgrown pyrite predominantly coexisting with pitchblende (Figure 8a,b). As the strata continue to uplift, the geothermal gradient continues to decrease, and the BSR processes regain dominance. In an open system, due to the unlimited availability of sulfate, the initial δ34S values of sulfate formed by sulfate-reducing bacteria at various stages will be similar, resulting in 34S-depleted pyrite with a limited δ34S value range. In a closed system, according to the Rayleigh isotope fractionation process [17], the sulfate supply is limited, and the pyrite formed at later stages consumes the initial sulfate, leading to increased sulfide deposition and progressively higher δ34S values. Consequently, the δ34S values of the sub-idiomorphic to idiomorphic cement pyrite exhibit heavier δ34S values (+9.16‰ to +16.77‰). Microscopic evidence and in situ sulfur isotope data strongly support the classical coupled fluid model (Model 3), providing evidence for the involvement of deep-seated reduced fluids (Figure 15).

5.3. Genesis of the Deposit

Using evidence from previous studies, combined with the elemental geochemistry and in situ sulfur isotope data obtained in this research, we propose a metallogenic model for the Liuhuanggou uranium deposit (Figure 16). The provenance of the Toutunhe Formation is primarily derived from the felsic igneous rocks of the North Tianshan and Central Tianshan regions. Previous studies on the uranium concentrations in intermediate–acidic volcanic rocks, pyroclastic rocks, and granite bodies in the Tianshan region indicate that their average uranium content exceeds 3 × 10⁻6, with individual granite samples reaching uranium concentrations as high as 9.45 × 10⁻6 [15], which may indicate favorable geochemical conditions.
Currently, industrial uranium orebodies in the Jurassic system have only been identified within the Toutunhe Formation, predominantly hosted in lithic feldspathic sandstone. The average uranium content in the gray sandstone of the Toutunhe Formation is higher than that in the yellow sandstone, suggesting that early uranium pre-enrichment occurred during the deposition of clastic materials sourced from the North Tianshan provenance area. From the Late Jurassic to Early Cretaceous, intense tectonic uplift and erosion led to the formation of a regional unconformity surface between the Lower Cretaceous and Upper Jurassic strata. The Middle–Lower Jurassic strata were tilted and exposed at the surface, forming a regional slope zone [29]. Meanwhile, the climatic environment transitioned from humid to arid-semiarid conditions, facilitating uranium mobilization and migration. This climatic shift promoted the infiltration of oxygen and uranium-bearing fluids, favoring the development of an interlayer oxidation zone-type U deposition. From the Late Cretaceous to Paleogene, the southern margin of the Junggar Basin experienced relatively stable tectonic conditions, which enabled uranium and oxygen-bearing groundwater to establish a hydrological circulation system within the strata. During this period, interlayer oxidation zones formed, and mobile uranium precipitated and accumulated under the influence of reductants in the mineralization-hosting sequences [30] (Figure 16a).
Since the Neogene, the southern margin of the Junggar Basin has undergone a rapid uplift and erosion, leading to intense deformation and folding in the foreland of the southern margin. This has caused the significant uplift and erosion of Jurassic strata [29], resulting in severe weathering. Most of the early interlayer oxidation zone-type U deposits were uplifted to the surface and subjected to erosion or reworking. For example, the Dashagou deposit on the southern flank of the Liuhuanggou Anticline has been almost completely eroded. At the same time, intense tectonic deformation destroyed early-formed oil and gas reservoirs, causing hydrocarbons to migrate along faults or unconformities to the surface. This led to widespread hydrocarbon reduction in the overlying strata, significantly impacting the preservation of ancient uranium deposits and the formation of new ones [32]. The upward migration of hydrocarbons has had two main effects on uranium mineralization in this area. On the one hand, it consumed a large amount of oxygen in the uranium-bearing aquifers, creating a strongly reducing environment in the mineralization-hosting layers, which played a role in concealing and preserving uranium deposits in the Toutunhe Formation. On the other hand, it greatly enhanced the reducing capacity of the sandstone, providing the necessary reducing conditions for later phreatic oxidation uranium mineralization. This accelerated the reduction, precipitation, and enrichment processes of uranium mineralization (Figure 16b).

6. Conclusions

(1) Based on morphological characteristics and paragenetic generations, the pyrite can be further classified into framboidal pyrite, concentric overgrown pyrite, and sub-idiomorphic to idiomorphic cement pyrite.
(2) The provenance of the ore-bearing sandstone in the Toutunhe Formation is the felsic igneous rocks from the North Tianshan and Central Tianshan regions.
(3) Sulfur isotope analysis indicates that the formation of pyrite involves both biotic and abiotic redox processes. Framboidal pyrite is primarily formed through bacterial sulfate reduction, while concentric overgrown pyrite precipitates via thermochemical sulfate reduction driven by hydrocarbon-rich fluids ascending from deeper sources. Sub-idiomorphic to idiomorphic cement pyrite forms through Rayleigh isotope fractionation associated with BSR.
(4) The uranium mineralization underwent two distinct stages. The early stage involved the initial enrichment of uranium due to the reaction between uranium-bearing fluids and reductants in the ore-bearing strata under the influence of groundwater dynamics. The later stage involved the upward migration of deep-seated oil and gas along faults, creating a strongly reducing environment. This process enhanced the reducing capacity of the sandstone, leading to further uranium enrichment and mineralization.

Author Contributions

Conceptualization, J.L., C.X. and S.C.; data curation, J.L. and M.L.; formal analysis, J.L. and Z.Y.; investigation, J.L., Y.Z., S.C., Z.Y., G.M., M.L., L.Y. and J.G.; methodology, J.L., C.X. and S.C.; project administration, Y.Z.; resources, J.L. and Y.Z.; writing—original draft, J.L. and Y.Z.; writing—review and editing, J.L., Y.Z., C.X. and S.C. All authors have read and agreed to the published version of the manuscript.

Funding

This study was jointly supported by the Natural Science Foundation of the Xinjiang Uygur Autonomous Region (2022D01A148), the Third-level Project of the China Geological Survey (DD20211550), and the Major Science and Technology Special Project of the Xinjiang Uygur Autonomous Region (2022A03009-3).

Data Availability Statement

The data are available upon request.

Acknowledgments

We thank the four anonymous reviewers for constructive reviews and significant contributions to improve the clarity and quality of this paper. We would like to express our gratitude to the Testing Center of Xinjiang Nonferrous Metals Geological Exploration Bureau and Guangzhou Tuoyan Testing Technology Co., Ltd., for their assistance during the experimental testing phase.

Conflicts of Interest

The authors declare no conflicts of interest. Among them, Authors Jie Gong are employees of Xinjiang Branch of China National Logging Corporation. The paper reflects the views of the scientists and not the company.

References

  1. Bonnetti, C.; Cuney, M.; Michels, R.; Truche, L.; Malartre, F.; Liu, X.; Yang, J. The multiple roles of sulfate-reducing bacteria and Fe-Ti oxides in the genesis of the Bayinwula roll front-type uranium deposit, Erlian Basin, NE China. Econ. Geol. 2015, 110, 1059–1081. [Google Scholar] [CrossRef]
  2. Reynolds, R.L.; Goldhaber, M.B.; Carpenter, D.J. Biogenic and nonbiogenic ore-forming processes in the south Texas uranium district: Evidence from the Panna Maria deposit. Econ. Geol. 1982, 77, 541–556. [Google Scholar] [CrossRef]
  3. Cuney, M. The extreme diversity of uranium deposits. Miner. Depos. 2009, 44, 3–9. [Google Scholar] [CrossRef]
  4. Cumberland, S.A.; Douglas, G.; Grice, K.; Moreau, J.W. Uranium mobility in organic material-rich sediments: A review of geological and geochemical processes. Earth-Sci. Rev. 2016, 159, 160–185. [Google Scholar] [CrossRef]
  5. Bhattacharyya, A.; Campbell, K.M.; Kelly, S.D.; Roebbert, Y.; Weyer, S.; Bernier Latmani, R.; Borch, T. Biogenic non-crystalline U (IV) revealed as major component in uranium ore deposits. Nat. Commun. 2017, 8, 15538. [Google Scholar] [CrossRef]
  6. Hazen, R.M.; Ewing, R.C.; Sverjensky, D.A. Evolution of uranium and thorium minerals. Am. Miner. 2009, 94, 1293–1311. [Google Scholar] [CrossRef]
  7. Jiao, Y.Q.; Wu, L.Q.; Peng, Y.B.; Rong, H.; Ji, D.M.; Miao, A.S.; Li, H.L. Sedimentary-tectonic setting of the deposition-type uranium deposits forming in the Paleo-Asian tectonic domain, North China. Earth Sci. Front. 2015, 22, 189–205. [Google Scholar]
  8. Cuney, M. Evolution of uranium fractionation processes through time: The secular variation of uranium deposit types. Econ. Geol. 2010, 105, 553–569. [Google Scholar] [CrossRef]
  9. Fayek, M.; Horita, J.; Ripley, E.M. The oxygen isotopic composition of uranium minerals: A review. Ore Geol. Rev. 2011, 41, 1–21. [Google Scholar] [CrossRef]
  10. Granger, H.C.; Warren, C.G. Unstable sulfur compounds and the origin of roll-type uranium deposits. Econ. Geol. 1969, 64, 160–171. [Google Scholar] [CrossRef]
  11. Warren, C.G. A method for discriminating between biogenic and chemical origins of the ore-stage pyrite in a roll-type uranium deposit. Econ. Geol. 1971, 66, 919–928. [Google Scholar] [CrossRef]
  12. Rackley, R.I. Environment of Wyoming Tertiary uranium deposits. Am. Assoc. Pet. Geol. Bull. 1972, 56, 755–774. [Google Scholar]
  13. Dahlkamp, F.J. Uranium Deposits of the World: Asia; Springer: Berlin/Heidelberg, Germany, 2009; pp. 21–24. [Google Scholar]
  14. Hall, S.M.; Mihalasky, M.J.; Tureck, K.R.; Hammarstrom, J.M.; Hannon, M.T. Genetic and grade and tonnage models for sandstone-hosted roll-type uranium deposits, Texas Coastal Plain, USA. Ore Geol. Rev. 2017, 80, 716–753. [Google Scholar] [CrossRef]
  15. Geng, Y.Y.; Liu, Z.Y.; Huang, S.H. Ore -forming environment and direction of mineralization of sandstone uranium ore in the Toutunhe Area, Southern margin of Junggar Basin. Uranium Geol. 2022, 38, 194–206. [Google Scholar]
  16. Bonnetti, C.; Zhou, L.; Riegler, T.; Brugger, J.; Fairclough, M. Large S isotope and trace element fractionations in pyrite of uranium roll front systems result from internally-driven biogeochemical cycle. Geochim. Et Cosmochim. Acta 2020, 282, 113–132. [Google Scholar] [CrossRef]
  17. Hough, G.; Swapp, S.; Frost, C.; Fayek, M. Sulfur isotopes in biogenically and abiogenically derived uranium roll-front deposits. Econ. Geol. 2019, 114, 353–373. [Google Scholar] [CrossRef]
  18. Barrie, C.D.; Boyce, A.J.; Boyle, A.P.; Williams, P.J.; Blake, K.; Ogawara, T.; Akai, J.; Prior, D.J. Growth controls in colloform pyrite. Am. Miner. 2009, 94, 415–429. [Google Scholar] [CrossRef]
  19. Rong, H.; Jiao, Y.Q.; Wu, L.Q.; Ji, D.M.; Li, H.L.; Zhu, Q.; Cao, M.Q.; Wang, X.M.; Li, Q.C.; Xie, H.L. Epigenetic alteration and its constraints on uranium mineralization from the Qianjiadian uranium deposit, southern Songliao Basin. Earth Sci. 2016, 41, 153–166. [Google Scholar]
  20. Wei, H.Y.; Wei, X.M.; Qiu, Z.; Song, H.Y.; Guo, S. Redox conditions across the G-L boundary in South China: Evidence from pyrite morphology and sulfur isotopic compositions. Chem. Geol. 2016, 440, 1–14. [Google Scholar] [CrossRef]
  21. Mahoney, C.; März, C.; Buckman, J.; Wagner, T.; Blanco-Velandia, V.O. Pyrite oxidation in shales: Implications for palaeo-redox proxies based on geochemical and SEM-EDX evidence. Sediment. Geol. 2019, 389, 186–199. [Google Scholar] [CrossRef]
  22. Jiao, Y.Q.; Wu, L.Q.; Rong, H.; Zhang, F.; Tao, Z.P.; Yue, L. Geological Modeling for Uranium Reservoir Heterogeneity: A Sedimentology Basis for Revealing Uranium Metallogenic Mechanism and Enhancing Uranium Recovery in Zhiluo Formation in Ordos Basin; Wang, F.L., Ed.; China University of Geosciences Press: Wuhan, China, 2021; pp. 106–113. [Google Scholar]
  23. IAEA. World Distribution of Uranium Provinces; International Atomic Energy Agency: Vienna, Austria, 2021. [Google Scholar]
  24. Ren, J.Q.; Huang, J.Q. Geotectonics and evolution in China. Sci. Press Rev. 1980, 32, 262–274. [Google Scholar]
  25. Li, J.Y.; Xiao, X.C.; Tang, Y.Q. Basic features of Late paleozoic plate Tectonics in the Karameri Region of East Junggar. Geol. Rev. 1990, 36, 305–316. [Google Scholar]
  26. Song, J.Y.; Qin, M.K.; Cai, X.Q. Basement structural characteristics of Junggar Basin and its influence on sandstone type uranium ore mineralization. Geol. Rev. 2015, 61, 128–138. [Google Scholar]
  27. Zhou, T.Q.; Wu, C.D.; Yu, B. New insights into multiple provebances evolution of the Jurassic from heavy minerals characteristics in southern Junggar Basin, NW CHINA. Pet. Explor. Dev. 2019, 46, 65–78. [Google Scholar] [CrossRef]
  28. Yao, C.; Guo, W.; Liu, J.; Li, H. Xinjiang Uygur Autonomous Region Bureau of Geology and Mineral Resources. In Regional Geology of Xinjiang Uygur Autonomous Region; Geological Publishing House: Beijing, China, 1993. [Google Scholar]
  29. Yan, J.J.; Jia, W.W.; Huang, S. Relationship between Middle-Cenozoic Tectonic evolution and Jurassic uranium mineralization in the Sulphur Gorge Area, southern margin of Junggar Basin. Uranium Geol. 2022, 38, 1022–1031. [Google Scholar]
  30. Chen, Z.L.; Lu, K.G.; Wang, G.; Chen, B.L.; Wang, G.R.; Zhang, E.J.; Cui, L.L.; Ding, W.J. Characteristics of cenozoic structural movements in southern margin of Junggar basin and its relationship to the mineralization of sandstone-type uranium deposits. Acta Petrol. Sin. 2010, 26, 457–470. [Google Scholar]
  31. He, Z.B.; Liu, Z.Y.; Yang, Y. Exploration of the relationship between tectonic-sedimentary evolution and sandstone-type uranium mineralization in the Junggar Basin during the Minddle Cenozoic. Xinjiang Geol. 2016, 34, 410–417. [Google Scholar]
  32. Huang, S.H.; Qin, M.K.; Liu, Z.Y. Constraints on sandstone uranium mineralization by diagenesis and hydrocarbon intrusion-example of sandstone uranium mineralization in the Toutunhe Foration, Liuhuanggou Area, Zhunan. J. Sedimentol. 2016, 34, 250–259. [Google Scholar]
  33. Li, Q.; Wu, B.L.; Zhou, Y. Sedimentary characteristics and uranium mineralization prospect analysis of the Toutunhe Formation in the Liuhuanggou Area of the southern margin of the Junggar Basin. J. Northwest Univ. 2023, 53, 635–654. [Google Scholar]
  34. Qi, L.; Jing, H. Determination of trace elements in granites by inductively coupled plasma mass spectrometry. Talanta 2000, 51, 507–513. [Google Scholar]
  35. Chen, L.; Chen, K.Y.; Bao, Z.A.; Liang, P.; Sun, T.T.; Yuan, H.L. Preparation of standards for in situ sulfur isotope measurement in sulfide using femtosecond laser ablation MC-ICP-MS. Java Authentication Auth. Serv. 2017, 32, 107–116. [Google Scholar] [CrossRef]
  36. Bao, Z.A.; Chen, L.; Zong, C.L.; Yuan, H.L.; Chen, K.Y.; Dai, M.N. Development of pressed sulfide powder tablets for in situ sulfur and lead isotope measurement using LA-MC-ICP-MS. Int. J. Mass Spectrom. 2017, 421, 255–262. [Google Scholar] [CrossRef]
  37. Nesbitt, H.W.; Young, G.M. Early Proteorzoi climates and Plate motion infemed from major element chemistry of lutites. Nature 1982, 299, 715–717. [Google Scholar] [CrossRef]
  38. Zhu, X.Y.; Wang, Y.L.; Wang, Z.C.; Zhang, C.J. Application of REE characteristics in the study of sandstone type uranium deposit: A case study of a uranium deposits in the Northern Sichuan Basin. Geol. Rev. 2005, 51, 401–408. [Google Scholar]
  39. Sun, S.S.; Mcdonough, W.F. Chemical and isotopic systematics of Oceanic Basalts:implications for mantle composition and processes. Geol. Soc. Lond. Spec. Publ. 1989, 42, 313–345. [Google Scholar] [CrossRef]
  40. Geng, Y.Y.; Liu, Z.Y.; He, Z.H.; Huang, S.H.; Guo, Q.; Xu, Q.; Song, J.Y. Provenance and ore-forming tectonic setting of sandstone-type uranium deposits in the southern margin of Junggar Basin-Insights from U-Pb ages and Hf isotopes of detrital zircons. Geol. Rev. 2020, 66, 393–409. [Google Scholar]
  41. Roser, B.P.; Korsch, R.J. Provenance signatures of sandstone-mudstone suites determined using discriminant function analysis of major-element date. Chem. Geol. 1988, 67, 119–139. [Google Scholar] [CrossRef]
  42. Ingham, E.S.; Cook, N.J.; Cliff, J.; Ciobanu, C.L.; Huddleston, A. A combined chemical, isotopic and microstructural study of pyrite from roll-front uranium deposits, Lake Eyre Basin, South Australia. Geochim. Et Cosmochim. Acta 2014, 125, 440–465. [Google Scholar] [CrossRef]
  43. Ohmoto, H. Systematics of sulfur and carbon isotopes in hydrothermal ore deposits. Econ. Geol. 1972, 67, 551–578. [Google Scholar] [CrossRef]
  44. Seal, R.R. Sulfur isotope geochemistry of sulfide minerals. Rev. Miner. Geochem. 2006, 61, 633–677. [Google Scholar] [CrossRef]
  45. Thode, H.G.; Monster, J.; Dunford, H.B. Sulphur isotope geochemistry. Geochim. Et Cosmochim. Acta 1961, 25, 159–174. [Google Scholar] [CrossRef]
  46. Kaplan, I.R.; Rittenberg, S.C. Microbiological fractionation of sulphur isotopes. J. Gen. Microbiol. 1964, 34, 195–212. [Google Scholar] [CrossRef]
  47. Gregory, D.D.; Kohn, M.J. Pyrite: Fool’s gold records starvation of bacteria. Am. Miner. 2020, 105, 282–283. [Google Scholar] [CrossRef]
  48. Yue, L.; Jiao, Y.Q.; Wu, L.Q.; Rong, H.; Xie, H.L.; Wang, Q.Y.; Yan, Q.Q. Selective crystallization and precipitation of authigenic pyrite during diagenesis in uranium reservoir sandbodies in Ordos Basin. Ore Geol. Rev. 2019, 107, 532–545. [Google Scholar] [CrossRef]
  49. Jensen, M. Sulfur isotopes and the origin of sandstone-type uranium deposits. Econ. Geol. 1958, 53, 598–616. [Google Scholar] [CrossRef]
  50. Cheney, E.S.; Jensen, M.L. Stable isotopic geology of the gas hills, Wyoming, Uranium District. Econ. Geol. 1966, 61, 44–71. [Google Scholar] [CrossRef]
  51. Austin, S.R. Some patterns of sulfur isotope distribution in uranium deposits. Earth Sci. Bull. 1970, 3, 243–252. [Google Scholar]
  52. Warren, C.G. Sulfur isotopes as a clue to the genetic geochemistry of a roll-type uranium deposit. Econ. Geol. 1972, 67, 759–767. [Google Scholar] [CrossRef]
  53. Goldhaber, M.B.; Reynolds, R.L.; Rye, R.O. Origin of a south Texas roll-typeuranium deposit: II. Sulfide petrology and sulfur isotope studies. Econ. Geol. 1978, 73, 1690–1705. [Google Scholar] [CrossRef]
  54. Reynolds, R.L.; Goldhaber, M.B. Iron disulfide minerals and the genesis of roll-type uranium deposit. Econ. Geol. 1983, 78, 105–120. [Google Scholar] [CrossRef]
  55. Fishman, N.S.; Reynolds, R.L. Origin of the Mariano Lake uranium deposit, McKinley County, New Mexico. AAPG Bull. 1986, A179, 211–226. [Google Scholar]
  56. Northrop, H.R.; Goldhaber, M.B.; Landis, G.P.; Unruh, J.W.; Reynolds, R.L.; Campbell, J.A.; Wanty, R.B.; Grauch, R.I.; Whitney, I.; Rye, R.O. Genesis of the tabular-type vanadium-uranium deposits of the Henry Basin, Utah. Econ. Geol. 1990, 85, 215–269. [Google Scholar] [CrossRef]
  57. Cai, C.; Li, H.; Qin, M.; Luo, X.; Wang, F.; Ou, G. Biogenic and petroleum-related oreforming processes in Dongsheng uranium deposit, NW China. Ore Geol. Rev. 2007, 32, 262–274. [Google Scholar] [CrossRef]
  58. Cai, C.; Dong, H.; Li, H.; Xiao, X.; Ou, G.; Zhang, C. Mineralogical and geochemical evidence for coupled bacterial uranium mineralization and hydrocarbon oxidation in the Shashagetai deposit, NW China. Chem. Geol. 2007, 236, 167–179. [Google Scholar] [CrossRef]
  59. Wulser, P.A.; Brugger, J.; Foden, J.; Pfeifer, H.R. The sandstone-hosted Beverley uranium deposit, Lake Frome Basin, South Australia: Mineralogy, geochemistry, and a time-constrained model for its genesis. Econ. Geolo. 2011, 106, 835–867. [Google Scholar] [CrossRef]
  60. Meek, A.S. Sandstone Uranium Deposits of Nebraska and Colorado: A Comparative Study. Master’s Thesis, University of Manitoba, Winnipeg, Manitoba, 2014; pp. 45–59. [Google Scholar]
  61. Bonnetti, C.; Liu, X.; Zhaobin, Y.; Cuney, M.; Michels, R.; Malartre, F.; Mercadier, J.; Cai, J. Coupled uranium mineralisation and bacterial sulphate reduction for the genesis of the Baxingtu sandstone-hosted U deposit, SW Songliao Basin, NE China. Ore Geol. Rev. 2017, 82, 108–129. [Google Scholar] [CrossRef]
  62. Lach, P.; Cathelineau, M.; Brouand, M.; Fiet, N. In-situ isotopic and chemical study of pyrite from Chu-Sarysu (Kazahkstan) roll-front uranium deposit. Procedia Earth Planet. Sci. 2015, 13, 207–210. [Google Scholar] [CrossRef]
  63. Liu, J.; Qiu, Y.; Zhou, J.; Wen, Z.; Fayek, M.; Zhang, H. Discussion on biogenic mineralization of sandstone-type uranium ore in Mengqiguer uranium mineral deposit. Sci. Technol. Eng. 2015, 15, 115–119. [Google Scholar]
  64. Chen, C.; Liu, H.J.; Hou, H.Q.; Han, S.Y.; Ke, D.; Bai, Y.S.; Ou, G.X.; Li, Y.R. The relationship between pyrite and sandstone-hosted uranium mineralization of the Zhiluo Formation in the northern Ordos Basin. Acta Geol. Sin. 2016, 90, 3375–3380. [Google Scholar]
  65. Pang, K. The Characteristics of In-Situ Stable Isotopes and Their Geological Significance About Sandstone Uranium Deposit in Northern Ordos Basin. Master’s Thesis, Xi’an Northwest University, Xi’an, China, 2018; pp. 39–44. [Google Scholar]
  66. Zhao, L.; Cai, C.; Jin, R.; Li, J.; Li, H.; Wei, J.; Guo, H.; Zhang, B. Mineralogical and geochemical evidence for biogenic and petroleum-related uranium mineralization in the Qianjiadian deposit, NE China. Ore Geol. Rev. 2018, 101, 273–292. [Google Scholar] [CrossRef]
  67. Chen, Y.; Jin, R.; Miao, P.; Li, J.; Guo, H.U.; Chen, L. Occurrence of pyrites in sandstone-type uranium deposits: Relationships with uranium mineralization in the North Ordos Basin, China. Ore Geol. Rev. 2019, 109, 426–447. [Google Scholar] [CrossRef]
  68. Ding, B.; Liu, H.X.; Zhang, B.; Li, P.; Jiang, H.; Zhang, H.J.; Xie, X.L.; Guo, C.J. Mineralogical and isotopes evidence for origin of pyrite: Implication for formation mechanism of pyrite and its relationship with uranium mineralization in Mengqigu’er uranium deposit, Yili Basin. Miner. Depos. 2019, 28, 1379–1391. [Google Scholar]
  69. Yi, C.; Wang, G.; Li, P.; Li, H.M.; Ding, B.; Zhang, K.; Zhang, Y. Characteristics of the ferrum phases in the Nalinggou uranium deposit, northern Ordos Basin, and its metallogenic significance. Acta Geol. Sin. 2019, 93, 470–486. [Google Scholar]
  70. Zhang, C.Y.; Nie, F.J.; Jiao, Y.Q.; Deng, W.; Peng, Y.B.; Hou, S.R.; Dai, M.J.; Ye, T.F. Characterization of ore-forming fluids in the Tamusu sandstone-type uranium deposit, Bayingobi Basin, China: Constraints from trace elements, fluid inclusions and C-O–S isotopes. Ore Geol. Rev. 2019, 111, 102999. [Google Scholar] [CrossRef]
  71. Zhang, L.; Liu, C.Y.; Lei, K.Y. Green altered sandstone related to hydrocarbon migration from the uranium deposits in the northern Ordos Basin, China. Ore Geol. Rev. 2019, 109, 482–493. [Google Scholar] [CrossRef]
  72. Huang, G.W.; Yu, F.C.; Pan, J.Y.; Cheng, Z.L.; Wu, D.H.; Xue, W.W.; Song, T.Z.; Li, S.P. Genesis of pyrite from the Mengqiguer uranium deposit in Ili Basin of Xinjiang and its implication for mineralization. Geol. China 2021, 48, 507–519. [Google Scholar]
  73. Yue, L.; Jiao, Y.Q.; Fayek, M.; Wu, L.Q.; Rong, H.; Xie, H.L. Transformation of Fe-Bearing Minerals from Dongsheng Sandstone-Type Uranium Deposit, Ordos Basin, North-Central China: Implications for Ore Genesis; American Mineralogist: Chantilly, VA, USA, 2021; Volume 107, pp. 1396–1409. [Google Scholar]
  74. Ishihara, S.; Sasaki, A. Sulfur isotopic ratios of the magnetite-series and ilmeniteseries granitoids of the Sierra Nevada batholith: A reconnaissance study. Geology 1989, 17, 788–791. [Google Scholar] [CrossRef]
  75. Tang, Y.Y.; Bi, X.W.; Fayek, M.; Hu, R.Z.; Wu, L.Y.; Zou, Z.C.; Feng, C.X.; Wang, X.S. Microscale sulfur isotopic compositions of sulfide minerals from the Jinding Zn-Pb deposit, Yunnan Province, Southwest China. Gondwana Res. 2014, 26, 594–607. [Google Scholar] [CrossRef]
  76. Rddad, L.; Mouguina, E.M. Sulfur and lead isotopic compositions of ore sulfides and mining economic potential of the high atlas mississippi valley-type ore province, morocco. J. Geochem. Explor. 2021, 226, 106765. [Google Scholar] [CrossRef]
  77. Machel, H.G.; Krouse, H.Y.; Sassen, R. Products and distinguishing criteria of bacterial and the rmochemical sulfate reduction. Appl. Geochem. 1995, 10, 373–389. [Google Scholar] [CrossRef]
  78. Machel, H.G.; Foght, J. Products and Depth Limits of Microbial Activity in Petroliferous Subsurface Settings. In Microbial Sediments; Riding, R., Ed.; Springer: Berlin/Heidelberg, Germany, 2000; pp. 105–120. [Google Scholar]
  79. Machel, H.G. Bacterial and thermochemical sulfate reduction in diagenetic settings-old and new insights. Sediment. Geol. 2001, 140, 143–175. [Google Scholar] [CrossRef]
Minerals 15 00575 g005
Figure 5. Hand specimens and photomicrographs of mineralized sandstone from the Toutunhe Formation, Liuhuanggou area. (a) Mineralized core; (b) organic-bearing lithic arkose; (c) gray mineralized pebble-bearing coarse-grained lithic arkose; (d) gray medium-sand-bearing coarse-grained lithic arkose. (Kf—Potassium Feldspar; Q—Quartz; Pl—Plagioclase Feldspar; Org—Organic Matter.).
Figure 5. Hand specimens and photomicrographs of mineralized sandstone from the Toutunhe Formation, Liuhuanggou area. (a) Mineralized core; (b) organic-bearing lithic arkose; (c) gray mineralized pebble-bearing coarse-grained lithic arkose; (d) gray medium-sand-bearing coarse-grained lithic arkose. (Kf—Potassium Feldspar; Q—Quartz; Pl—Plagioclase Feldspar; Org—Organic Matter.).
Minerals 15 00575 g005
Minerals 15 00575 g006
Figure 6. Backscattered electron (BSE) image of uranium minerals in the mineralization-hosting sandstone of the Toutunhe Formation, Liuhuanggou area. (a) Distribution characteristics of uranium minerals; (b) relationship between uranium minerals and clay minerals; (c) relationship between uranium minerals and multi-stage pyrite; (d) relationship between uranium minerals and multi-stage pyrite. (Py—Pyrite; Q—Quartz; Pit—Pitchblende). The white box in Figure 6a shows the approximate coverage area of Figure 6b.
Figure 6. Backscattered electron (BSE) image of uranium minerals in the mineralization-hosting sandstone of the Toutunhe Formation, Liuhuanggou area. (a) Distribution characteristics of uranium minerals; (b) relationship between uranium minerals and clay minerals; (c) relationship between uranium minerals and multi-stage pyrite; (d) relationship between uranium minerals and multi-stage pyrite. (Py—Pyrite; Q—Quartz; Pit—Pitchblende). The white box in Figure 6a shows the approximate coverage area of Figure 6b.
Minerals 15 00575 g006
Minerals 15 00575 g007
Figure 7. Spider diagrams of (a) rare earth elements (REEs) and (b) trace elements for uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area. Normalization values are referenced from [39].
Figure 7. Spider diagrams of (a) rare earth elements (REEs) and (b) trace elements for uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area. Normalization values are referenced from [39].
Minerals 15 00575 g007
Minerals 15 00575 g008
Figure 8. Backscattered electron images revealing the textural relationship among authigenic. framboids (i), the concentric overgrown pyrite (ii), and the sub-idiomorphic to idiomorphic cement pyrite (iii). The dashed lines denote the boundaries between populations of mineralization-stage pyrite. The red, green, and blue dashed circles respectively represent the LA-MC-ICP-MS measurements of sulfur isotopes on framboidal, concentric overgrown pyrite, and cement pyrite. The δ34S values (in ‰) indicated on the photographs are presented in Table 4. (a) Textural relationships and sulfur isotopic compositions between the framboids pyrite and the concentric overgrown pyrite pyrites; (b) Textural relationships and sulfur isotopic compositions between the framboids pyrite and the concentric overgrown pyrite pyrites; (c) Textural relationships and sulfur isotopic compositions between the concentric overgrown pyrite and the sub-idiomorphic to idiomorphic cement pyrite; (d) Textural relationships and sulfur isotopic compositions between the concentric overgrown pyrite and the sub-idiomorphic to idiomorphic cement pyrite.
Figure 8. Backscattered electron images revealing the textural relationship among authigenic. framboids (i), the concentric overgrown pyrite (ii), and the sub-idiomorphic to idiomorphic cement pyrite (iii). The dashed lines denote the boundaries between populations of mineralization-stage pyrite. The red, green, and blue dashed circles respectively represent the LA-MC-ICP-MS measurements of sulfur isotopes on framboidal, concentric overgrown pyrite, and cement pyrite. The δ34S values (in ‰) indicated on the photographs are presented in Table 4. (a) Textural relationships and sulfur isotopic compositions between the framboids pyrite and the concentric overgrown pyrite pyrites; (b) Textural relationships and sulfur isotopic compositions between the framboids pyrite and the concentric overgrown pyrite pyrites; (c) Textural relationships and sulfur isotopic compositions between the concentric overgrown pyrite and the sub-idiomorphic to idiomorphic cement pyrite; (d) Textural relationships and sulfur isotopic compositions between the concentric overgrown pyrite and the sub-idiomorphic to idiomorphic cement pyrite.
Minerals 15 00575 g008
Minerals 15 00575 g009
Figure 9. Histogram of the sulfur isotope for different types of pyrite from the Liuhuanggou area, southern margin of Junggar Basin.
Figure 9. Histogram of the sulfur isotope for different types of pyrite from the Liuhuanggou area, southern margin of Junggar Basin.
Minerals 15 00575 g009
Minerals 15 00575 g010
Figure 10. Characteristics of fluid inclusions under microscope in the Liuhuanggou area. (a) Hydrocarbon inclusions within feldspar dissolution pores under plane-polarized light; (b) blue fluorescent hydrocarbon inclusions are observed within feldspar dissolution pores under fluorescence microscopy; (c) the maximum fluorescence emission wavelength is 495 nm, which corresponds to the fluorescent characteristics of aromatic hydrocarbons.
Figure 10. Characteristics of fluid inclusions under microscope in the Liuhuanggou area. (a) Hydrocarbon inclusions within feldspar dissolution pores under plane-polarized light; (b) blue fluorescent hydrocarbon inclusions are observed within feldspar dissolution pores under fluorescence microscopy; (c) the maximum fluorescence emission wavelength is 495 nm, which corresponds to the fluorescent characteristics of aromatic hydrocarbons.
Minerals 15 00575 g010
Minerals 15 00575 g011
Figure 11. Contour map of sand’s thickness in the lower sub-segment (J2t1-1) of the lower part of the Toutunhe Formation.
Figure 11. Contour map of sand’s thickness in the lower sub-segment (J2t1-1) of the lower part of the Toutunhe Formation.
Minerals 15 00575 g011
Minerals 15 00575 g012
Figure 12. Provenance discriminant function diagram for uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area [41].
Figure 12. Provenance discriminant function diagram for uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area [41].
Minerals 15 00575 g012
Minerals 15 00575 g013
Figure 13. Compilation of δ34S values for mineralization-stage pyrite in sandstone-hosted U deposits around the world. Data sources include [1,2,16,17,42,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73].
Figure 13. Compilation of δ34S values for mineralization-stage pyrite in sandstone-hosted U deposits around the world. Data sources include [1,2,16,17,42,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73].
Minerals 15 00575 g013
Minerals 15 00575 g014
Figure 14. Characteristics of oil inclusion under microscope in the Liuhuanggou area. Yellow-brown oil inclusions within quartz grains.
Figure 14. Characteristics of oil inclusion under microscope in the Liuhuanggou area. Yellow-brown oil inclusions within quartz grains.
Minerals 15 00575 g014
Minerals 15 00575 g015
Figure 15. Models for formation of pyrite.
Figure 15. Models for formation of pyrite.
Minerals 15 00575 g015
Minerals 15 00575 g016
Figure 16. Genetic model diagram of the Liuhuanggou uranium deposit. (a) Early-stage mineralization; (b) Late-stage mineralization.
Figure 16. Genetic model diagram of the Liuhuanggou uranium deposit. (a) Early-stage mineralization; (b) Late-stage mineralization.
Minerals 15 00575 g016
Table 1. Major element composition (wt%) of uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area. TFe2O3 represents the total iron expressed as ferric oxide. The Chemical Index of Alteration (CIA = 100 × [Al2O3/(Al2O3 + CaO* + Na2O + K2O)]) is used to indicate the degree of chemical alteration in rocks during weathering processes.
Table 1. Major element composition (wt%) of uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area. TFe2O3 represents the total iron expressed as ferric oxide. The Chemical Index of Alteration (CIA = 100 × [Al2O3/(Al2O3 + CaO* + Na2O + K2O)]) is used to indicate the degree of chemical alteration in rocks during weathering processes.
Sample NumberLithologySampling Depth/mSiO2Al2O3TFe2O3MgOCaONa2OK2OP2O5MnOTiO2LOlFeOFe2O3CIA
GSY53-6-1Gray pebble-bearing coarse-grained arkose622.03–622.2379.1111.141.570.020.832.583.180.050.020.202.500.590.9154.78
GSY53-6-2642.08–642.2880.0311.171.370.020.542.193.090.050.020.292.030.600.7058.47
GSY53-6-3644.08–644.2377.0311.702.300.030.982.422.950.060.030.464.840.921.2856.59
GSY53-6-4674.08–674.2875.3311.261.580.094.322.723.020.050.090.304.610.670.8441.87
GSY53-6-6679.64–679.8472.5610.272.360.146.992.862.870.050.140.226.010.821.4533.33
GSY53-6-7Gray medium- to fine-grained arkose691.48–691.6876.1411.861.810.051.932.972.830.070.050.733.180.601.1450.80
GSY53-6-8Gray pebble-bearing coar
se-grained arkose		693.48–693.6878.2710.991.640.041.512.973.040.060.040.312.330.600.9750.10
GSY53-6-9Gray medium- to coarse-grained arkose610.50–610.7077.8211.891.920.020.852.723.140.050.020.342.310.980.8355.74
Table 2. Rare earth element (REE) compositions of uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area (10−6).
Table 2. Rare earth element (REE) compositions of uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area (10−6).
Sample NumberLaCePrNdSmEuGdTbDyHoErTmYbLuYΣREELREEHREELREE/HREEδEuδCe
GSY53-6-120.8043.104.9018.703.700.923.160.492.780.551.660.261.720.2714.1117.1192.1224.993.690.821.05
GSY53-6-221.2042.104.7018.003.400.903.030.492.740.551.660.281.770.2913.9115.0190.3024.713.650.861.03
GSY53-6-327.7054.406.3023.704.601.084.160.744.310.892.720.432.850.4622.8157.14117.7839.362.990.751.01
GSY53-6-420.1039.204.5017.103.400.883.190.533.140.651.880.301.960.3116.6113.7485.1828.562.980.821.01
GSY53-6-614.2028.603.2012.402.500.752.570.472.800.581.740.261.700.2715.987.9461.6526.292.340.901.04
GSY53-6-734.3067.107.7029.005.401.184.650.784.330.852.790.463.060.4922.4184.49144.6839.813.630.721.01
GSY53-6-826.4051.205.9022.804.201.073.940.623.590.742.280.372.410.4019.5145.42111.5733.853.300.801.01
GSY53-6-925.4050.405.7021.904.101.043.660.553.240.652.010.322.210.3516.8138.33108.5429.793.640.821.03
Table 3. Trace element compositions of uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area (10−6).
Table 3. Trace element compositions of uranium-bearing sandstone in the Toutunhe Formation, Liuhuanggou area (10−6).
Sample NumberLiBeScVCrCoNiCuZnGaGeAsRbSrZr
GSY53-6-16.801.183.4035.714.85.539.497.5614.611.41.189.1291.414896.4
GSY53-6-25.980.963.0232.813.54.197.035.6815.39.601.185.8377.6120109
GSY53-6-37.461.745.3875.427.510.314.711.671.512.81.2724.285.1155238
GSY53-6-45.221.124.3934.615.85.347.986.979.6611.11.134.9987.5171103
GSY53-6-64.141.093.9338.212.46.439.1314.025.29.611.1318.080.940288.3
GSY53-6-75.611.286.8351.029.26.439.398.0616.612.51.114.7584.9163319
GSY53-6-85.191.124.3934.116.66.979.326.7122.911.41.105.9788.9146138
GSY53-6-98.271.194.9243.022.27.9211.57.6722.312.21.115.2294.7130150
Sample NumberNbMoCdInSbCsBaHfTaWTlPbBiThU
GSY53-6-110.94.970.050.020.321.686471.661.190.830.5612.80.084.714.97
GSY53-6-28.612.550.050.020.301.484511.440.910.660.4710.20.084.803.66
GSY53-6-311.625.00.320.061.192.035522.661.221.300.7216.90.127.7279.5
GSY53-6-49.211.410.040.020.431.775361.660.940.730.5211.50.074.515.33
GSY53-6-66.593.630.130.030.781.545861.400.680.550.5411.40.063.7220.2
GSY53-6-713.32.290.050.040.411.935012.801.301.100.4811.00.109.5813.2
GSY53-6-89.401.670.040.020.301.745752.000.950.790.5311.50.106.708.08
GSY53-6-99.460.950.030.030.291.955661.970.950.990.5512.00.085.932.27
Table 4. In situ sulfur isotope composition of pyrite in uranium-bearing sandstone from the Toutunhe Formation, Liuhuanggou area.
Table 4. In situ sulfur isotope composition of pyrite in uranium-bearing sandstone from the Toutunhe Formation, Liuhuanggou area.
Pyrite Typesδ34SV-CDT (‰)2σ
The framboids pyrite−12.230.38
−16.850.43
−8.650.37
−2.660.34
−11.901.35
−0.840.33
2.160.35
−6.690.44
−3.730.22
−7.170.57
−12.930.56
The concentric overgrown pyrite−7.860.22
−0.750.37
−0.070.30
2.880.27
1.390.21
−0.890.49
−2.130.21
−2.670.46
−3.780.55
−1.680.24
−2.480.31
5.110.24
10.320.24
The sub-idiomorphic to idiomorphic cement pyrite14.450.15
13.620.06
14.960.14
16.770.20
14.850.20
14.430.22
15.420.20
15.030.11
11.710.69
9.160.41
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Li, J.; Zhou, Y.; Xue, C.; Chen, S.; Ma, G.; Yang, Z.; Liu, M.; Yang, L.; Gong, J. Constraints from Geochemistry of Mineralization-Hosting Sandstone and Sulfur Isotopes of Pyrite on Uranium Mineralization in the Liuhuanggou Area, Southern Junggar Basin. Minerals 2025, 15, 575. https://doi.org/10.3390/min15060575

AMA Style

Li J, Zhou Y, Xue C, Chen S, Ma G, Yang Z, Liu M, Yang L, Gong J. Constraints from Geochemistry of Mineralization-Hosting Sandstone and Sulfur Isotopes of Pyrite on Uranium Mineralization in the Liuhuanggou Area, Southern Junggar Basin. Minerals. 2025; 15(6):575. https://doi.org/10.3390/min15060575

Chicago/Turabian Style

Li, Junyang, Yu Zhou, Chunji Xue, Shizhong Chen, Guoxiong Ma, Zuohuai Yang, Min Liu, Le Yang, and Jie Gong. 2025. "Constraints from Geochemistry of Mineralization-Hosting Sandstone and Sulfur Isotopes of Pyrite on Uranium Mineralization in the Liuhuanggou Area, Southern Junggar Basin" Minerals 15, no. 6: 575. https://doi.org/10.3390/min15060575

APA Style

Li, J., Zhou, Y., Xue, C., Chen, S., Ma, G., Yang, Z., Liu, M., Yang, L., & Gong, J. (2025). Constraints from Geochemistry of Mineralization-Hosting Sandstone and Sulfur Isotopes of Pyrite on Uranium Mineralization in the Liuhuanggou Area, Southern Junggar Basin. Minerals, 15(6), 575. https://doi.org/10.3390/min15060575

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop