New Evidence of Submarine Exhalative Sedimentation in the Uranium-Polymetallic Phosphorite Deposit in Baizhuyu, Hunan, China
by
,
Zhixing Li
1,2, 
Mingkuan Qin
1,2,*,
Yuqi Cai
1,2,*,
Longsheng Yi
1,2
,
Wenquan Wang
1,2,
Jian Wang
1,2 and
Longlong Li
3 1
CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, Beijing 100029, China
2
CNNC Beijing Research Institute of Uranium Geology, Beijing 100029, China
3
Oil Production Plant 6 of PetroChina Changqing Oilfield Company, Yulin 719000, China
*
Authors to whom correspondence should be addressed.
Minerals 2022, 12(7), 826; https://doi.org/10.3390/min12070826
Submission received: 5 May 2022
/
Revised: 19 June 2022
/
Accepted: 23 June 2022
/
Published: 29 June 2022
Abstract
:There are as many as 25 kinds of minerals (including non-ferrous metals, ferrous metals, rare and dispersed elements, precious metals, non-metallic and energy minerals) enriched in uranium-polymetallic fertile beds in black rock series, which is therefore widely attracting scholars all over the world. However, there is still great controversy in terms of the metallogenic mechanism in such beds. The black rock series have been systematically sampled from the Baizhuyu deposit in northwestern Hunan Province, China based on field geological and radioactivity surveys. Major and trace elements as well as rare earth elements (REE) of uranium-polymetallic phosphorite and its wall rocks were analyzed. Furthermore, carbon and oxygen isotopes, Sm-Nd isotopes, and mineralogy of the Baizhuyu deposit were studied. The results show that dolomite is a normal marine sediment, while and uranium-polymetallic elements were pre-enriched in phosphorites and black carbonaceous argillaceous shales and slates that formed from marine sedimentation and submarine exhalative sedimentation. Hydrothermal reworking to uranium-polymetallic phosphorites is significant as a result of submarine exhalative sedimentation. The research results of this paper can support a better understanding of metallogenesis and the future exploration of uranium-polymetallic phosphorite in the Lower Cambrian Niutitang Formation in the study area.
1. Introduction
Black rock series, widely distributed worldwide, mainly formed on a global scale in semi-deep sea-deep sea, swamp, or stagnant coastal-shallow sea environments, and consist of dark gray-black siliceous rocks, carbonaceous rocks, argillaceous rocks (tuffs), and their metamorphosed rocks [1,2,3,4]. They occur in the Lesser Himalayas of India, Iran, northern Pakistan, southern France, Wales, England, the Netherlands, Germany, Russia, northern Oman, southern Australia, Canada, Mongolia, Central Asia, and China [5]. In China, the black rock series formed from the Proterozoic to Tertiary. They are mainly located in the eastern, western, and northern margins of the Yangtze terrain, and the southern and northern margins of the North China and Tarim landmasses [6]. Uranium-polymetallic phosphorites, as a member of the black rock series, are commonly found at the base of the Lower Cambrian. There are as many as 25 kinds of minerals (including non-ferrous metals, ferrous metals, rare and dispersed elements, precious metals, non-metallic and energy minerals), which have a close genetic and spatial relationship with the uranium-polymetallic fertile beds in the black rock series, and often formed in large-super large deposits [7,8,9,10,11,12].
The Baizhuyu deposit is one of the few Ni-Mo polymetallic deposits that is being mined from the black rock series. Moreover, this kind of deposit, in which Ni and Mo coexist and both reach the economic mining conditions, is rare in the world [13,14,15]. The metallogenic mechanism of uranium-polymetallic phosphorite in the Lower Cambrian Niutitang Formation is still controversial. There are five main points of view. (1) Genesis of celestial impact, which is according to the unique element assemblage and Ir anomaly characteristics of the black rock series at the bottom of the Lower Cambrian in South China. Fan Delian proposed that platinum group elements (PGE), Co, and Ni might have been sourced from other places [16,17]. (2) Genesis of normal marine sediments, given that the Mo isotopic composition of the polymetallic rich beds of the black rock series is principally consistent with the values of modern seawater and the ore-forming age is consistent with the stratigraphic age of the Niutitang Formation, so it is speculated that the Ni-Mo polymetallic rich beds are normal marine sedimentary deposits [18,19,20,21]. (3) Genesis of submarine hydrothermal exhalation, because the extraordinary polymetallic enrichment in the black rock series has been found to be closely related to submarine exhalative sedimentation [13,22,23,24,25,26]. (4) Genesis of magmatic volcanic debris, which was raised by Luo Taiyi, who believes that alkaline-ultramafic magmatic activity exists during the Early Cambrian in the deep part of the Ni-Mo ore bed in the Songlin mining area of Zunyi, and the dominant material source is in deep magmatic rock. The metallogenic process experienced magmatism, hydrothermal sedimentation, and mechanical sedimentation, which is the product of the strong eruption period of deep magmatic activity [27,28]. (5) Biogenesis [29].
In this study, aiming at the systematic anatomy of the Baizhuyu uranium-polymetallic deposit in northwestern Hunan, on the basis of geological and radiological investigations of the black rock series in South China, samples collected from tunnel sections in the Baizhuyu deposit were analyzed for major elements, trace elements, and rare earth elements as well as carbon and oxygen isotopes and Sm-Nd isotopes, and were also studied through the Advanced Mineral Identification and Characterization System (AMICS), an automatic mineral parameter quantitative analysis tool. We aimed to place a better understanding on: (1) the elemental geochemical characteristics of the uranium-polymetallic fertile beds and its upper and lower host rocks; (2) the mineralogical characteristics of the uranium-polymetallic phosphorite; and (3) the enrichment mechanism of the uranium-polymetallic phosphorite.
2. Geological Characteristics of the Baizhuyu Deposit
Figure 1 illustrates the uranium-polymetallic phosphorite deposit in Baizhuyu. The stratigraphic structure is relatively stable regionally. The Lower Cambrian Niutitang Formation uranium-polymetallic phosphorite is the main ore-bearing bed of the Baizhuyu deposit. It is exposed along two wings of Cili depression. It has a clear boundary with the underlying gray-white massive dolomite of the Sinian Dengying Formation and the overlying black carbonaceous argillaceous shale and slate of the Lower Cambrian Niutitang Formation. Occurrence, morphology, distribution, and scale of the uranium-polymetallic phosphorite layers were controlled by wavy landform of the ancient denudation surface of the Dengying Formation. The thickness of the uranium-polymetallic phosphorite layer varied (20~40 cm) in the Cili depression area. Additionally, uranium-bearing phosphorites could be observed at the bottom. The layer of black carbonaceous-argillaceous shales and slates of the Niutitang Formation was above the uranium-polymetallic phosphorite layer. The lithological conditions and stratigraphic contact relation are shown in Figure 2.
3. Materials and Methods
Thorough sampling of the uranium-polymetallic phosphorite layer in the Baizhuyu deposit was conducted. Four samples were taken every 10 cm. Meanwhile, two samples from the underlying dolomites and four samples from the overlying black shales were collected. Figure 2 shows the detailed sampling sites and sample numbers.
All of the studied samples were crushed and pulverized to 200 meshes before being analyzed. The major, trace, and rare earth elements of all samples, the C, O isotopes, and Sm-Nd isotopes of the uranium polymetallic phosphorite samples were analyzed. All analyses mentioned were completed at the Beijing Research Institute of Uranium Geology (BRIUG).
The major elements of the samples were determined by X-ray fluorescence spectrometer (XRF, PW2404 by Phillips) at a relative humidity of 33% and temperature of 23 °C. The trace and rare earth elements of samples were determined by inductively coupled plasma mass spectrometer (ICP-MS, ELEMENT XR) at a relative humidity of 30% and temperature of 20 °C. C and O isotopes of the samples were determined by mass spectrometer (MAT 253). PDB was employed as the standard for δ13C, while PDB and SMOW were employed as the standards for δ18O. The Sm-Nd isotopes of the samples were determined by a thermal surface ionization mass spectrometer (TIMS, ISOPROBE-T, by GV UK), at a relative humidity of 30% and temperature of 20 °C. The error was down to 2σ.
The mineral composition and characteristics were studied through the automatic quantitative analysis of mineral parameters at the Analytical Laboratory of BRIUG. The automatic mineral parameter quantitative analysis system consisted of a ZESS sigma300 high resolution field emission scanning electron microscope, BrukerXflash6130 X-ray spectrometer, and automatic mineral analysis data processing software. The test conditions were high vacuum mode, working voltage 20 KV, working distance 9.5–10 mm, aperture 120 μm.
4. Results
4.1. Geochemical Results of Major Elements
The major elemental composition of the dolomite, uranium-polymetallic phosphorite and black carbonaceous-argillaceous shales and slates are listed in Table 1. Dolomites were mainly composed of CaO and MgO, of which the average contents were 29.59% and 20.09%, respectively; the average content of SiO2 was 3.13%; and the average content of loss on ignition (LOI) was 44.28%. The uranium-polymetallic phosphorites were mainly composed of CaO and P2O5, of which the average contents were 38.4% and 30.6%, respectively; the average content of SiO2 was 9.56%; and the average content of LOI was 10.06%. Black carbonaceous-argillaceous shales and slates are mainly composed of SiO2, of which the average content was 61.89%; the average contents of Al2O3 and K2O were 12.99% and 4.13%, respectively; and the average content of LOI was 13.78%. From the bottom (i.e., dolomite) to the top (i.e., shales and slates), the contents of SiO2, Al2O3, K2O, and Fe2O3 increased, the content of CaO in the overlying black carbonaceous-argillaceous shales and slates decreased drastically, and P2O5 was significantly enriched in the uranium-polymetallic phosphorite layer of the Lower Cambrian Niutitang Formation.
4.2. Geochemical Results of Trace Elements
The trace elements (U, Ni, and Mo) were enriched in the dolomites, uranium-polymetallic phosphorites, and black carbonaceous-argillaceous shales and slates when compared with the upper crust. Herein, uranium-polymetallic phosphorites exhibited the maximum enrichment coefficients. The grades of U, Ni, and Mo reached their minable industrial index of China and compared with the upper crust, the average enrichment coefficients of U, Ni, and Mo in the uranium-polymetallic phosphorites were 482.1, 341.1, and 1402.5, respectively [31]. Re, Tl, and V reached the Chinese minable industrial index as byproducts of the uranium deposit and the average enrichment coefficients of Re, Tl and V in the uranium-polymetallic phosphorites were 2.7, 40.0, and 14.6, respectively [32]. Figure 3 shows the primitive mantle standardized cobweb map of averages of some trace elements in dolomites, uranium-polymetallic phosphorites, and carbonaceous-argillaceous shales and slates. As observed, these samples exhibited similar primitive mantle standardized distribution curves, while the enrichment coefficients of Ba, U, La, P, Sm and Y in the uranium-polymetallic phosphorites were higher than those in the other two kinds of ores.
The content of Ba tends to be extremely low in modern seawater, but relatively high in submarine hydrothermal fluids. Hence, Ba is a key indicator element of hydrothermal sedimentation [33,34]. In hydrothermal sedimentation environments, uranium tends to be enriched due to accelerated sedimentation [35,36]. In the dolomites, as shown in Table 2, the contents of Ba were 71.2 × 10−6~122 × 10−6 (average = 96.6 × 10−6, average enrichment-deficit coefficient with the upper crust = 0.18), the Sr/Ba ratios were 0.79~1.92 (average = 1.36), and the U/Th ratios were 3.48~4.88 (average = 4.18). In uranium-polymetallic phosphorites, the contents of Ba were 6167 × 10−6~8424 × 10−6 (average = 7471.5 × 10−6, average enrichment-deficit coefficient with the upper crust = 13.58), the Sr/Ba ratios were 0.06~0.08 (average = 0.07), and the U/Th ratios were 653.11~1083.78 (average = 821.48). In black carbonaceous-argillaceous shales and slates, the contents of Ba were 1057 × 10−6~2267 × 10−6 (average = 1631.3 × 10−6, average enrichment-deficit coefficient with the upper crust = 2.97), the Sr/Ba ratios were 0.01~0.04 (average = 0.03), and the U/Th ratios were 3.3~3.98 (average = 3.65).
Abnormal enrichments of V, Cu, Zn, and Ba, which are indicator elements of hydrothermal fluids [37,38,39], were also frequently observed. The average enrichment-deficit coefficients of V in dolomites, uranium-polymetallic phosphorites, and black carbonaceous-argillaceous shales and slates with the upper crust were 0.72, 14.56, and 16.82, respectively. The average enrichment-deficit coefficients of Cu in dolomites, uranium-polymetallic phosphorites, and black carbonaceous-argillaceous shales and slates with the upper crust were 0.82, 12.2, and 2.10, respectively. The average enrichment-deficit coefficients of Zn in dolomites, uranium-polymetallic phosphorites, and black carbonaceous-argillaceous shales and slates with the upper crust were 1.24, 8.91, and 1.49, respectively. The average enrichment-deficit coefficients of Ba in dolomites, uranium-polymetallic phosphorites, and black carbonaceous-argillaceous shales and slates compared with the upper crust were 0.18, 13.58, and 2.97, respectively.
4.3. Geochemical Results of REE
As shown in Figure 4b, normalized by North American shale composites (NASC), the REE distribution curves of the dolomites, uranium-polymetallic phosphorites, and carbonaceous-argillaceous shales and slates in the Baizhuyu deposit were horizontal or slightly inclined to the left. The overall average contents of REE in the dolomites, carbonaceous-argillaceous shales and slates, and uranium-polymetallic phosphorites were 25.07 ppm, 133.36 ppm, and 533.17 ppm, respectively.
For the dolomites, δCe was 0.5~0.52 (average = 0.51) and δEu was 0.88~0.91 (average = 0.90). For the uranium-polymetallic phosphorites, the δCe was 0.44~0.46 (average = 0.45) and the δEu was 1.24~1.29 (average = 1.26). For carbonaceous-argillaceous shales and slates, the δCe was 0.88~0.90 (average = 0.89) and the δEu was 0.85~0.95 (average = 0.89).
Figure 4a illustrates the w (La)/w (Yb)-w (∑REE) of samples collected from the Baizhuyu deposit. As observed, uranium-polymetallic phosphorite samples were located in the intersecting area of alkaline rocks and granites; black carbonaceous-argillaceous shales and slates samples were located in the intersecting area of alkaline and sedimentary rocks (one sample) and the area of sedimentary rocks (three samples, near the areas of alkaline rocks and granites); the dolomite samples were located in the area of sedimentary rocks.
4.4. Results of C, O Isotopic Analysis
Compositions of light C, O isotopes can provide information about the fluid provenance [40]. Table 3 shows the C, O isotopic data of the uranium-polymetallic phosphorite samples.
The δ13CPDB of marine sedimentary carbonates in crust is usually 0‰ and remain unchanged during the diagenetic process [41,42]; the δ13CPDB of mantle-originated igneous rocks is usually −5‰ [40]; the δ13CPDB of granites in South China is usually −37.9~−7.5‰ [43]. The δ18O of detrital sedimentary rocks is usually aligned with that of the original rocks. However, the overall δ18OSMOW of detrital sedimentary rocks is between that of unaltered volcanic rocks (5~15‰) and that of clay minerals (20~30‰) due to weathering and the components of clay minerals. The δ18OSMOW of shales and submarine sediments is typically 5~25‰, while the δ18OSMOW of modern marine limestones is typically 28~30‰ [44].
The δ13CV-PDB of the uranium-polymetallic phosphorite samples was −3.4~−3.8‰, with an average of −3.6‰; the δ18OV-SMOW of uranium-polymetallic phosphorite samples was 16.5~18.4‰, with an average of 17.2‰. The δ13CV-PDB of the uranium-polymetallic phosphorite samples was between that of the marine sedimentary carbonates in the crust and mantle-originated igneous rocks and close to that of the mantle-originated igneous rocks. The δ18OV-SMOW of the uranium-polymetallic phosphorite samples was between that of the shales and that of the submarine sediments. The C, O isotopes indicate hydrothermal reworking during conventional sedimentations.
4.5. Results of Sm-Nd Isotopic Analysis
Table 4 lists the Sm-Nd isotopic composition of the uranium-polymetallic phosphorite samples. Indeed, Nd isotopes can effectively reflect the provenance components and characteristics of sediments. McLennan et al. [45] claimed that the εNd of sediments originated from the ancient upper crust are usually below −10, while the εNd of sediments (rocks) originated from mid-ocean ridge basalt (MORB) are usually above +5. The εNd (0) of the uranium-polymetallic phosphorites in the Baizhuyu deposit was −21.26~−16.03 (see Table 4).
4.6. Results of Mineralogical Analysis
Based on the microscopic observation of the uranium-polymetallic phosphorites samples, further mineralogical analysis was undertaken using the Advanced Mineral Identification and Characterization System (AMICS). The results showed that the phosphorite was mainly composed of apatite and quartz, both of which account for about 90% weight percentage, therein, the apatite was 81.138% and the quartz 8.586%. Second, it also contained molybdenite, anhydrite, illite, pentlandite, pyrite, barite, uraninite, sphalerite, kaolinite, and rutile. The weight percentages were 3.429%, 1.478%, 1.426%, 1.352%, 1.027%, 0.533%, 0.355%, 0.011%, 0.005%, 0.002%, and 0.001%, respectively. Uraninite, molybdenite, pentlandite, pyrite, and anhydrite were mainly distributed along the fractures. Molybdenum mainly exists in molybdenite, and nickel mainly exists in pyrite. For the space occupation of some of the major minerals, see Figure 5.
5. Discussion
Investigations of the geochemical characteristics of trace elements in the dolomite, uranium-polymetallic phosphorite, and black carbonaceous-argillaceous shales and slates from the Baizhuyu Deposit indicate that these samples had similar primitive mantle standardized distribution curves, suggesting similar provenances. Additionally, V, Cu, Zn, and Ba, which are indicator elements of hydrothermal fluids, were abnormally enriched in the samples of the uranium-polymetallic phosphorite and black carbonaceous-argillaceous shales and slates [37,38,39]. The enrichment-deficit coefficients of V, Cu, Zn, and Ba in the uranium-polymetallic phosphorite samples with the upper crust were 14.56, 12.2, 8.91, and 13.58, respectively. The enrichment-deficit coefficients of V, Cu, Zn, and Ba in the samples of black carbonaceous-argillaceous shales and slates with the upper crust were 16.82, 2.10, 1.49, and 2.97, respectively. The enrichment-deficit coefficients of V, Cu, Zn, and Ba in the dolomite samples with the upper crust were −0.72, −0.82, 1.24, and −0.18, respectively. The Sr/Ba ratio has also been widely used for the determination of rock provenance [34]. Previous studies have demonstrated that rock provenances of hydrothermal fluids and sedimentation are characterized by Sr/Ba ratio < l and Sr/Ba ratio > 1, respectively. The average Sr/Ba ratios of the samples of dolomite, uranium-polymetallic phosphorite, and black carbonaceous-argillaceous shales and slates were 1.36, 0.07, and 0.03, respectively. Likewise, geochemical characteristics of the trace elements demonstrate that hydrothermal fluids were present in the formations of uranium-polymetallic phosphorites and black carbonaceous-argillaceous shales and slates in the Baizhuyu deposit, but not in that of the dolomites in the Baizhuyu deposit.
Some studies have concluded that normal seawater sedimentations are characterized by the enrichment of light REE, resulting in right-inclined curves and abnormally positive Ce. The hydrothermal sedimentation curves are horizontal or slightly inclined, the light/heavy REE ratio is small, and Ce is abnormally negative [46]. Indeed, the ΣREE of normal seawater tends to be extremely low and REE-enriched sediments can barely be observed. Hence, high contents of REE in sediments are indicators of hydrothermal sedimentations. Some scholars have claimed that abnormally positive Eu is an indicator that highly reductive hydrothermal fluids are injected or that ocean basalts inherit the characteristics of the origin after submarine alteration [46,47,48]. This proposal has been widely supported. For instance, Michard et al. [49] reported that hydrothermal fluids in hydrothermal vents in the East Pacific Ocean and metallic sediments in the Galapagos Rift and the Red Sea hot brine pool had significantly abnormal positive Eu. The standardized distribution curves of REE in the NASC in the samples of dolomite, uranium-polymetallic phosphorite, and black carbonaceous-argillaceous shales and slates were horizontal or slightly inclined to the left and Ce was abnormally negative. The content of REE was minimized in dolomites, with an overall average of 25.07 ppm, and the average δEu of 0.90. The content of REE was maximized in the uranium-polymetallic phosphorites, with an overall average of 533.17 ppm, and the average δEu of 1.26. The overall average content of REE in carbonaceous-argillaceous shales and slates was 133.36 ppm and the average δEu was 0.89. According to w (La)/w (Yb)-w (∑REE), the uranium-polymetallic phosphorite and black carbonaceous-argillaceous shales and slates were located in the intersecting area of alkaline and sedimentary rocks or near the areas of alkaline rocks and granites. The characteristics of REE indicate the presence of hydrothermal reworking during the formation of uranium-polymetallic phosphorites and black carbonaceous-argillaceous shales and slates, especially uranium-polymetallic phosphorites. Additionally, hydrothermal modification is absent in the formation of dolomites.
The average δ13CV-PDB of the uranium-polymetallic phosphorite samples was −3.6‰, while that of the marine sedimentary carbonates in the crust and mantle-originated igneous rocks were 0‰ and −5‰, respectively. The average δ18OV-SMOW of the uranium-polymetallic phosphorite samples was 17.2‰, which was within the range of those of the shales and submarine sediments (5~25‰). The εNd (0) was −21.26~−16.03, indicating that uranium-polymetallic phosphorites originated from the ancient upper crust and indirectly demonstrated the presence of hydrothermal modifications during the formation of uranium-polymetallic phosphorites.
The results of the microscopic observation and automatic quantitative analysis of mineral parameters showed that the uranium polymetallic phosphorite was mainly composed of apatite and quartz. Uraninite, molybdenite, pentlandite, pyrite, and anhydrite were mainly distributed along the fractures. There also existed molybdenite and pentlandite, barite, and rutile, which are typical hydrothermal minerals, indicating that hydrothermal alteration occurred on the basis of the marine sediments.
6. Conclusions
(1) The dolomites in the Sinian Dengying Formation of the Baizhuyu deposit are mainly composed of CaO and MgO. The uranium-polymetallic phosphorites are mainly composed of CaO and P2O5,. The black carbonaceous argillaceous shales and slates had the highest SiO2 content, followed by Al2O3 and K2O, and the uranium-polymetallic phosphorite belonged to the transitional type. From bottom to top, the contents of SiO2, Al2O3, K2O, and Fe2O3 increased, the contents of CaO in the overlying black carbonaceous-argillaceous shales and slates decreased drastically, and P2O5 was significantly enriched in the uranium-polymetallic phosphorite layer at the bottom of the Lower Cambrian Niutitang Formation.
(2) Based on the field geological and radioactivity surveys, a comprehensive analysis of the major elements, trace elements, and REE of the samples of dolomite, uranium-polymetallic phosphorite and black carbonaceous-argillaceous shales and slates as well as the C, O isotopes, Sm-Nd isotopes, and mineralogical characteristics of uranium-polymetallic phosphorite demonstrate that the provenance of dolomites is marine sedimentation, while the provenances of uranium-polymetallic phosphorites and black carbonaceous-argillaceous shales and slates are marine sedimentation and submarine exhalative sedimentation. Uranium-polymetallic pre-enrichment occurred during the formation of phosphorite and carbonaceous argillaceous shales and slates. Meanwhile, hydrothermal reworking is evident in the uranium-polymetallic phosphorites, indicating the presence of submarine exhalative sedimentation during the formation of uranium-polymetallic phosphorites in the Baizhuyu deposit.
The research results of this paper can support a better understanding of the metallogenic theory and regularity on the unique uranium-polymetallic phosphorite in the Lower Cambrian Niutitang Formation in China, and will assist in the uranium exploration in the study area.
Author Contributions
Writing (original draft), Z.L.; Writing (review and editing), Z.L., M.Q., Y.C. and L.Y.; Supervision, M.Q. and Y.C.; Data curation, W.W., J.W. and L.L. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by the CNNC Bureau of Geology (202143-5, 202246-6, 201493).
Data Availability Statement
The data presented in this study are contained within the article.
Acknowledgments
We are grateful for all the funding that supported this research and thank the editors and anonymous reviewers for the journal Minerals.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Fan, D.L.; Ye, J.; Yang, R.Y.; Hong, Z.X. The geological events and ore mineralization nearby the Precambrian-Cambrian boundary in Yangtze platform. Acta Sedimentol. Sin. 1987, 5, 81–95, (In Chinese with English abstract). [Google Scholar]
- Zhang, A.Y.; Wu, D.M.; Guo, L.N.; Wang, Y.L. The Geochemistry of Marine Black Shale Formation and Its Metallogenic Significance; Science Press: Beijing, China, 1987; (In Chinese with English abstract). [Google Scholar]
- Wang, J.G.; Chen, D.Z.; Wang, D.; Yan, D.T.; Zhou, X.Q.; Wang, Q.C. Petrology and geochemistry of chert on the marginal zone of Yangtze platform, western Hunan, South China, during the Ediacaran-Cambrian transition. Sedimentology 2012, 59, 809–829. [Google Scholar] [CrossRef]
- Liu, S.C.; Ning, S.Y.; Zheng, D.S. Petrogenesis and sedimentary environment of black rock series of the Lower Cambrian Shuigoukou Formation in South Qinling. Acta Geol. Sin. 2021, 95, 549–564, (In Chinese with English abstract). [Google Scholar]
- Mao, J.W. Trends in the study of deposits related to black shales. Miner. Depos. 2001, 20, 402–403, (In Chinese with English abstract). [Google Scholar]
- Li, Z.X.; Qin, M.K.; Liu, X.Y.; Wang, W.W.; Wang, J.; Li, L.L. Characteristics, genesis and research significances of multi-elements enrichment layer of black rock series. Uranium Geol. 2022, 39, 14–26, (In Chinese with English abstract). [Google Scholar]
- Qi, F.C.; Zhang, Z.L.; Li, Z.X.; Wang, Z.M.; He, Z.B.; Wang, W.Q. Unconventional uranium resources in China. Uranium Geol. 2011, 27, 193–199, (In Chinese with English abstract). [Google Scholar]
- Chang, B.; Wen, H.J. EMPA research on nickel and molybdenum minerals in Ni-Mo sulfide layer of the lower Cambrian black rock series at Huangjiawan, Zunyi, Guizhou Province. Acta Mineral. Sin. 2008, 28, 439–446, (In Chinese with English abstract). [Google Scholar]
- Yu, B.S.; Dong, H.; Widom, E.; Chen, J.Q.; Lin, C.S. Re-Os and Nd isotopic characteristics of the Lower Cambrian black shale from the Northern Tarim Basin and their correlation with the Yangtze Platform. Sci. China (Series. D Earth Sci.) 2004, 34, 83–88. (In Chinese) [Google Scholar]
- Meyers, P.; Pratt, L.; Nagy, B. Introduction to geochemistry of metalliferous black shales. Chem. Geol. 1992, 99, 7–11. [Google Scholar] [CrossRef] [Green Version]
- Chen, L. Sedimentology and Geochemistry of the Early Cambrian Black Rock Series in the Hunan-Guizhou Area, China. Ph.D. Dissertation, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China, 2006. (In Chinese with English abstract). [Google Scholar]
- Wang, D.H. Study on critical mineral resources: Significance of research, determination of types, attributes of resources, progress of prospecting, problems of utilization, and direction of exploitation. Acta Geol. Sin. 2019, 93, 1189–1209, (In Chinese with English abstract). [Google Scholar]
- Coveney, R.M., Jr.; Murowchick, J.B.; Grauch, R.I.; Glascock, M.D.; Denison, J.R. Gold and platinum in shales with evidence against extraterrestrial sources of metals. Chem. Geol. 1992, 99, 101–114. [Google Scholar] [CrossRef]
- Horan, M.F.; Morgan, J.W.; Grauch, R.I.; Coveney, R.M., Jr.; Murowchick, J.B.; Hulbert, L.J. Rhenium and osmium isotopes in black shales and Ni-Mo-PGE-rich sulfide layers, Yukon Territory, Canada, and Hunan and Guizhou provinces, China. Geochim. Cosmochim. Acta 1994, 58, 257–265. [Google Scholar] [CrossRef]
- Orberger, B.; Pasava, J.; Gallien, J.P.; Daudin, L.; Pinti, D.L. Biogenic and abiogenic hydrothermal sulfides: Controls of rare metal distribution in black shales (Yukon Territories, Canada). J. Geochem. Explor. 2003, 78, 559–563. [Google Scholar] [CrossRef]
- Fan, D.L. Polyelements in the Lower Cambrian Black Shale Series in Southern China, The significance of trace elements in solving petrogenetic problems and controversies. 1983; 447–474. [Google Scholar]
- Fan D., L.; Yang R., Y.; Huang, Z.X. The Lower Cambrian black shale series and the iridium anomaly in South China Developments in Geosciences; Science press: Beijing, China, 1984; pp. 215–224. [Google Scholar]
- Mao, J.W.; Lehmann, B.; Du, A.D.; Zhang, G.D.; Ma, D.S.; Wang, Y.T.; Zeng, M.G.; Kerrich, R. Re-Os dating of polymetallic Ni-Mo-PGE-Au mineralization in lower Cambrian black shales of South China and its geologic significance. Econ. Geol. 2002, 97, 1051–1061. [Google Scholar] [CrossRef]
- Li, S.R.; Xiao, Q.Y.; Shen, J.F.; Sun, L.; Liu, B.; Yan, B.H. Re-Os isotopic constraints on the source of platinum group elements and mineralization age of Lower Cambrian in Hunan and Guizhou. Chin. Sci. (Ser. D Earth Sci.) 2002, 32, 568–575. (In Chinese) [Google Scholar]
- Jiang, S.Y.; Yang, J.H.; Ling, H.F.; Feng, H.Z.; Chen, Y.Q.; Chen, J.H. Re-Os isotopes and PGE geochemistry of black shales and intercalated Ni-Mo polymetallic sulfide bed from the Lower Cambrian Niutitang Formation, South China. Prog. Nat. Sci. 2003, 13, 788–794. [Google Scholar] [CrossRef]
- Wille, M.; Nägler, T.F.; Lehmann, B.; SchrÖder, S.; Kramers, J.D. Hydrogen sulphide release to surface waters at the Precambrian/Cambrian boundary. Nature 2008, 453, 767–769. [Google Scholar] [CrossRef]
- Coveney, R.M., Jr.; Chen, N.S. Ni-Mo-PGE-Au-rich ores in Chinese black shales and speculations on possible analogues in the United States. Miner. Depos. 1991, 26, 83–88. [Google Scholar] [CrossRef]
- Mao, J.W.; Zhang, G.D.; Du, A.D.; Wang, Y.T.; Zeng, M.G. Geology, geochemistry, and Re-Os isotopic dating of the Huangjiawan Ni-Mo-PGE deposit, Zunyi, Guizhou Province: With a discussion of the polymetallic mineralization of basal Cambrian black shales in South China. Acta Geol. Sin. 2001, 75, 234–243, (In Chinese with English abstract). [Google Scholar]
- Yang, R.D.; Zhu, L.J.; Gao, H.; Zhang, W.H.; Jiang, L.J.; Wang, Q.; Bao, M. A study on characteristics of the hydrothermal vent and relating biota at the Cambrian bottom in Songlin, Zunyi County, Guizhou Province. Geol. Rev. 2005, 51, 481–493, (In Chinese with English abstract). [Google Scholar]
- Qi, F.C.; Li, Z.X.; Wang, W.Q.; Yang, Z.Q.; Zhang, Y. Uranium polymetallic ore-forming process of gas solution in marine phosphorite of northwestern Hunan. Miner. Depos. 2015, 34, 179–188, (In Chinese with English abstract). [Google Scholar]
- Wang, W.Q.; Qi, F.C.; Lin, W.J.; Li, Z.X. The existing forms of uranium and genesis of Ni-Mo polymetallic layer in the Songlin area, Zunyi. Acta Geol. Sin. 2021, 95, 1843–1853, (In Chinese with English abstract). [Google Scholar]
- Luo, T.Y.; Zhang, H.; Li, X.B.; Zhu, D. Mineralization characteristics of the multi-element-rich strata in the Niutitang Formation black shale series Zunyi Guizhou China. Acta Mineral. Sin. 2003, 23, 296–302, (In Chinese with English abstract). [Google Scholar]
- Luo, T.Y.; Ning, X.X.; Luo, Y.L.; Li, X.B.; Ning, R.X.; Yao, L.B. Uper-enrichment of Se in the bottom black shales lower Cambrian at Zunyi Guizhou province, China. Acta Mineral. Sin. 2005, 25, 275–282, (In Chinese with English abstract). [Google Scholar]
- Shi, C.H.; Cao, J.; Hu, K.; Han, S.C.; Bian, L.Z.; Yao, S.P. A review on origin of Ni-Mo polymetallic deposits in lower Cambrian black rock series in south China. Geol. Rev. 2011, 57, 718–730, (In Chinese with English abstract). [Google Scholar]
- Li, Z.X.; Qin, M.K.; Wang, W.Q.; Wang, J.; Han, H.Z. Geochemical characteristics of Baizhuyu U-polymetallic phosphorite deposit. Uranium Geol. 2022, 38, 25–37, (In Chinese with English abstract). [Google Scholar]
- Han, Y.W.; Ma, Z.D.; Zhang, H.F.; Zhang, B.R.; Li, F.L.; Gao, S.; Bao, Z.Y. Geochemistry, 2nd ed.; Geology Press: Beijing, China, 2004; pp. 46–47. (In Chinese) [Google Scholar]
- DZ/T 0199–2015; Specifications for uranium mineral exploration. Standards Press of China: Beijing, China, 2015. (In Chinese)
- Li, S.R.; Gao, Z.M. Silicalite of hydrothermal origin in the Lower Cambrian black rock series of south China. Acta Mineral. Sin. 1996, 16, 416–422, (In Chinese with English abstract). [Google Scholar]
- Zhou, H.B. Geochemical Characteristics and Geological Significance of the Lower Cambrian Black Rock Series in Northwestern Hunan. Ph.D. Dissertation, East China University of Technology, Nanchang, China, 2019. (In Chinese with English abstract). [Google Scholar]
- Rona, P.A. Criteria for recognition of hydrothermal mineral deposits in oceanic crust. Econ. Geol. 1978, 73, 135–160. [Google Scholar] [CrossRef]
- Guo, H.Y.; Xia, Y.; He, S.; Xie, Z.J.; Wei, D.T.; Lei, B. Geochemical characteristics of Zhijin phosphorite rare-earth deposit in Guizhou, China. Acta Mineral. Sin. 2017, 37, 755–763, (In Chinese with English abstract). [Google Scholar]
- Kametakaa, M.; Takebeb, M.; Nagaic, H.; Zhud, S.; Takayanagi, Y. Sedimentary environments of the Middle Permian phosphorite-chert complex from the northeastern Yangtze platform, China; the Gufeng Formation: A continental shelf radiolarian chert. Sediment. Geol. 2005, 174, 197–222. [Google Scholar] [CrossRef]
- Goldberg, T.; Strauss, H.; Guo, Q.; Liu, C.Q. Reconstructing marine redox conditions for the Early Cambrian Yangtze Platform: Evidence from biogenic sulphur and organic carbon isotopes. Palaeogeogr. Palaeocl. 2007, 254, 175–193. [Google Scholar] [CrossRef]
- Jia, L.L.; Dai, T.; You, X.; Liu, Y.; Fu, S.; Ouyang, L. Trace element geochemistry of V-Ni-Mo deposits from the Lower Cambrian black rock series of Northwestern Hunan. Earth Sci. Front. 2012, 19, 260–265, (In Chinese with English abstract). [Google Scholar]
- Hoefs, J. Stable Isotope Geochemistry; Springer: New York, NY, USA, 1973. [Google Scholar]
- Faure, G. Principles of Isotope Geology; Wiley: Hoboken, NJ, USA, 1977. [Google Scholar]
- Schidlowski, M. Beginnings of terrestrial life: Problems of the early record and implications for extraterrestrial scenarios. In Proceedings of the SPIE-The International Society for Optical Engineering, San Diego, CA, USA, 6 July 1998. [Google Scholar]
- Zhao, Z.F.; Zheng, Y.F.; Wei, C.S. Carbon concentration and isotope composition of granites from Southeast China. Phys. Chem. Earth Part A Solid Earth Geod. 2001, 26, 821–833. [Google Scholar] [CrossRef]
- Zheng, Y.F. Stable Isotope Geochemistry; Science Press: Beijing, China, 2000. (In Chinese) [Google Scholar]
- McLennan, S.M.; Taylor, S.R.; McCulloch, M.T. Geochemical and Nd-Sr isotopic composition of deep-sea turbidites: Crustal evolution and plate tectonic associations. Geochim. Et Cosmochim. Acta 1990, 54, 2015–2050. [Google Scholar] [CrossRef]
- Fryer, B.I. Rare-earth evidence in iron-formations for changing Precambrian oxidation states. Geochim. Cosmochim. Acta 1977, 41, 361–367. [Google Scholar] [CrossRef]
- Joseph, L.G., Jr. Rare earth elements, iron formations and sea water. Geochim. Cosmochim. Acta 1978, 42, 1845–1850. [Google Scholar]
- Yi, H.S.; Peng, J.; Xia, W.J. The late Precambrian paleo-ocean evolution of the Southeast Yangtze continental margin: REE record. Acta Sedimentol. Sin. 1995, 13, 131–137, (In Chinese with English abstract). [Google Scholar]
- Michard, A.; Albarède, F.; Michard, G.; Minster, J.F.; Charlou, J.L. Rare earth elements and uranium in high-temperature solutions from East Pacific Rise hydrothermal vent field (13N). Nat. Lond. 1983, 303, 795–797. [Google Scholar] [CrossRef]
Figure 1.
A schematic of the lithologic profile and sampling of the Baizhuyu deposit [30].
Figure 1.
A schematic of the lithologic profile and sampling of the Baizhuyu deposit [30].
Figure 2.
The lithological conditions of the uranium-polymetallic phosphorite layer and its contact with the upper and lower country rocks: (a) Contact of the Dengying–Niutitang Formations; (b) grey-white, thick, massive dolomite of the Dengying Formation (the arrowed points); (c) uranium-polymetallic phosphorite layer (the arrowed points); (d) black carbonaceous-argillaceous shales and slates (the arrowed points).
Figure 2.
The lithological conditions of the uranium-polymetallic phosphorite layer and its contact with the upper and lower country rocks: (a) Contact of the Dengying–Niutitang Formations; (b) grey-white, thick, massive dolomite of the Dengying Formation (the arrowed points); (c) uranium-polymetallic phosphorite layer (the arrowed points); (d) black carbonaceous-argillaceous shales and slates (the arrowed points).
Figure 3.
The standardized cobweb map of the trace elements in the primitive mantle.
Figure 4.
(a) A schematic of w (La)/w (Yb)-w (∑REE) in the Baizhuyu deposit; (b) the average NASC - normalized distribution curves of REE in samples collected from the Baizhuyu deposit.
Figure 4.
(a) A schematic of w (La)/w (Yb)-w (∑REE) in the Baizhuyu deposit; (b) the average NASC - normalized distribution curves of REE in samples collected from the Baizhuyu deposit.
Figure 5.
The backscattering image of the uranium-polymetallic phosphorite. Ap—Apatite; Pn—Pentlandite; Py—Pyrite; Mo—Molybdenite; Anh—Anhydrite; Qtz—Quartz; Ur—Uraninite; Brt—Barite. (a) Spatial relationship of minerals; (b) pitchblende, gypsum and pyrite distributed along fractures; (c) strawberry pyrite; (d) Mass distribution of nickel pyrite and molybdenite.
Figure 5.
The backscattering image of the uranium-polymetallic phosphorite. Ap—Apatite; Pn—Pentlandite; Py—Pyrite; Mo—Molybdenite; Anh—Anhydrite; Qtz—Quartz; Ur—Uraninite; Brt—Barite. (a) Spatial relationship of minerals; (b) pitchblende, gypsum and pyrite distributed along fractures; (c) strawberry pyrite; (d) Mass distribution of nickel pyrite and molybdenite.
Table 1.
The major elements of the samples from the Baizhuyu deposit (wB/%).
| Sample No. | BJY-9 | BJY-8 | BJY-7 | BJY-6 | BJY-5 | BJY-4 | BJY-3 | BJY-2 | BJY-1 | BJY-0 |
|---|---|---|---|---|---|---|---|---|---|---|
| Lithology | Black Carbonaceous-Argillaceous Shales and Slates | Uranium-Polymetallic Phosphorites | Dolomites | |||||||
| SiO2 | 68.45 | 62.29 | 59.4 | 57.41 | 11.04 | 9.82 | 7.81 | 8.88 | 3.54 | 2.72 |
| Al2O3 | 12.5 | 13.77 | 13.24 | 12.43 | 2.01 | 1.86 | 1.54 | 1.43 | 1.16 | 0.774 |
| Fe2O3 | 3.18 | 1.69 | 2.47 | 2.76 | 1.68 | 1.84 | 1.43 | 1.5 | 0.84 | 0.419 |
| MgO | 1.54 | 1.63 | 1.6 | 1.4 | 0.512 | 0.522 | 0.449 | 0.513 | 19.94 | 20.23 |
| CaO | 0.22 | 1.12 | 2.43 | 3.29 | 39.72 | 36.94 | 38.53 | 37.42 | 29.27 | 29.9 |
| Na2O | 0.39 | 0.191 | 0.147 | 0.076 | 0.34 | 0.32 | 0.264 | 0.226 | 0.065 | 0.09 |
| K2O | 3.86 | 4.46 | 4.23 | 3.97 | 0.362 | 0.347 | 0.325 | 0.351 | 0.261 | 0.152 |
| MnO | 0.006 | 0.007 | 0.007 | 0.007 | <0.004 | <0.004 | <0.004 | 0.004 | 0.019 | 0.016 |
| TiO2 | 0.517 | 0.622 | 0.604 | 0.585 | 0.082 | 0.07 | 0.062 | 0.073 | 0.061 | 0.03 |
| P2O5 | 0.05 | 0.07 | 0.06 | 0.14 | 30.05 | 29.94 | 31.81 | 30.23 | 0.95 | 0.71 |
| LOI | 9.06 | 13.85 | 15.81 | 16.4 | 11.71 | 9.78 | 8.68 | 9.28 | 43.79 | 44.77 |
| FeO | 0.51 | 0.88 | 0.81 | 0.72 | 0.79 | 0.71 | 0.61 | 0.79 | 0.38 | 0.36 |
| ∑ | 99.78 | 99.7 | 99.99 | 98.46 | 97.51 | 91.44 | 90.9 | 89.91 | 99.9 | 99.81 |
Table 2.
The analytical results of the trace elements and rare earth elements in the Baizhuyu deposit (wB/10−6).
Table 2.
The analytical results of the trace elements and rare earth elements in the Baizhuyu deposit (wB/10−6).
| Sample No. | BJY-9 | BJY-8 | BJY-7 | BJY-6 | BJY-5 | BJY-4 | BJY-3 | BJY-2 | BJY-1 | BJY-0 |
|---|---|---|---|---|---|---|---|---|---|---|
| Lithology | Black Carbonaceous-Argillaceous Shales and Slates | Uranium-Polymetallic Phosphorites | Dolomites | |||||||
| U | 28.2 | 28.1 | 23.3 | 26.8 | 1156 | 1403 | 1604 | 1236 | 3.83 | 3.1 |
| Ni | 73.4 | 59.3 | 63 | 92.3 | 4769 | 8233 | 6711 | 7575 | 44.2 | 38.3 |
| Mo | 164 | 184 | 147 | 179 | 1844 | 2624 | 1981 | 1966 | 40.2 | 29.8 |
| V | 987 | 1241 | 915 | 894 | 832 | 1011 | 722 | 929 | 49 | 37.5 |
| Re | 0.156 | 0.193 | 0.123 | 0.121 | 0.996 | 1.39 | 0.798 | 1 | 0.007 | 0.009 |
| Tl | 2.42 | 7.63 | 9.82 | 9.81 | 21.7 | 39.8 | 26.2 | 32.2 | 0.205 | 0.097 |
| Cu | 53.1 | 46.9 | 50.2 | 59.4 | 244 | 348 | 309 | 319 | 31.2 | 9.81 |
| Co | 7.12 | 1.63 | 3.46 | 4.95 | 20.2 | 34.3 | 30.5 | 31.6 | 2.28 | 1.42 |
| Zn | 215 | 50.5 | 74.7 | 82.6 | 410 | 619 | 752 | 750 | 95.4 | 80 |
| Cr | 95.9 | 103 | 101 | 84.6 | 48.9 | 58.3 | 61.1 | 56 | 10.1 | 5.7 |
| Rb | 115 | 136 | 124 | 118 | 11.7 | 12.4 | 11.2 | 11 | 7.26 | 4.67 |
| K | 32,043 | 37,023 | 35,114 | 32,956 | 3005 | 2880 | 2697 | 2913 | 2166 | 1261 |
| Ba | 1904 | 2267 | 1057 | 1297 | 7988 | 7307 | 8424 | 6167 | 122 | 71.2 |
| Th | 8.15 | 7.26 | 7.06 | 6.74 | 1.77 | 1.95 | 1.48 | 1.49 | 1.1 | 0.635 |
| Nb | 10.3 | 12.7 | 11.6 | 10.7 | 1.56 | 1.45 | 1.06 | 0.932 | 1.86 | 0.639 |
| La | 29.9 | 33.3 | 31.8 | 31.9 | 125 | 147 | 151 | 142 | 6.34 | 4.33 |
| Ce | 52 | 53.9 | 53.3 | 53.9 | 102 | 121 | 121 | 110 | 7.04 | 4.17 |
| Sr | 21.6 | 35.9 | 35.7 | 51.5 | 462 | 531 | 523 | 480 | 95.9 | 137 |
| Nd | 25.6 | 22.5 | 23.2 | 23.5 | 99.2 | 122 | 120 | 111 | 7.39 | 4.2 |
| P | 222 | 301 | 240 | 589 | 131,156 | 130,676 | 138,837 | 131,941 | 4163 | 3103 |
| Zr | 130 | 145 | 141 | 136 | 24.1 | 15.9 | 12.8 | 28.9 | 16.2 | 12.5 |
| Hf | 3.58 | 3.97 | 3.78 | 3.82 | 0.515 | 0.458 | 0.201 | 0.193 | 0.319 | 0.239 |
| Sm | 4.93 | 3.34 | 3.61 | 3.65 | 18.7 | 23.1 | 22.6 | 20.9 | 1.56 | 0.905 |
| Ti | 3099 | 3728 | 3620 | 3507 | 491 | 419 | 371 | 437 | 365 | 179 |
| Y | 45.9 | 25.8 | 27.1 | 27.5 | 373 | 451 | 469 | 410 | 19.6 | 12.1 |
| Yb | 4.3 | 2.9 | 3.03 | 3.19 | 13.2 | 16 | 17.8 | 15.2 | 0.951 | 0.653 |
| Lu | 0.558 | 0.415 | 0.403 | 0.415 | 1.52 | 1.9 | 2.11 | 1.62 | 0.189 | 0.095 |
| δU | 1.82 | 1.84 | 1.82 | 1.85 | 2 | 2 | 2 | 2 | 1.83 | 1.87 |
| U/Th | 3.46 | 3.87 | 3.3 | 3.98 | 653.11 | 719.49 | 1083.78 | 829.53 | 3.48 | 4.88 |
| Sr/Ba | 0.01 | 0.02 | 0.03 | 0.04 | 0.06 | 0.07 | 0.06 | 0.08 | 0.79 | 1.92 |
| ΣREE | 143.54 | 133.4 | 133.41 | 135.36 | 470.39 | 567.48 | 572.56 | 522.25 | 31.18 | 18.96 |
| L∑REE | 119.89 | 119.92 | 118.75 | 120 | 372.6 | 446.98 | 448.27 | 415.28 | 24.26 | 14.72 |
| H∑REE | 23.65 | 13.48 | 14.66 | 15.36 | 97.79 | 120.5 | 124.29 | 106.97 | 6.92 | 4.25 |
| LREE/HREE | 5.07 | 8.89 | 8.1 | 7.81 | 3.81 | 3.71 | 3.61 | 3.88 | 3.5 | 3.47 |
| La/Yb | 6.95 | 11.48 | 10.5 | 10 | 9.47 | 9.19 | 8.48 | 9.34 | 6.67 | 6.63 |
| Ce/La | 1.74 | 1.62 | 1.68 | 1.69 | 0.82 | 0.82 | 0.8 | 0.77 | 1.11 | 0.96 |
| δCe | 0.89 | 0.88 | 0.9 | 0.89 | 0.46 | 0.46 | 0.45 | 0.44 | 0.52 | 0.5 |
| δEu | 0.95 | 0.87 | 0.87 | 0.85 | 1.26 | 1.26 | 1.24 | 1.29 | 0.91 | 0.88 |
δU = 2U/(U + Th/3) (Wignall, 1994).
Table 3.
The C, O isotopic characteristics of the uranium-polymetallic phosphorite samples collected from the Baizhuyu deposit (wB/‰).
Table 3.
The C, O isotopic characteristics of the uranium-polymetallic phosphorite samples collected from the Baizhuyu deposit (wB/‰).
| SN. | Sample No. | Lithology | δ13CV-PDB | δ18OV-PDB | δ18OV-SMOW |
|---|---|---|---|---|---|
| 1 | BJY-5 | uranium-polymetallic phosphorite | −3.4 | −13.5 | 17 |
| 2 | BJY-4 | −3.8 | −14 | 16.5 | |
| 3 | BJY-3 | −3.7 | −13.6 | 16.9 | |
| 4 | BJY-2 | −3.5 | −12.1 | 18.4 | |
| Average | −3.6 | −13.3 | 17.2 | ||
Table 4.
The Sm-Nd isotopic composition of the samples from the Baizhuyu deposit.
| SN. | Sample No. | Lithology | Sm [×10−6] | Nd [×10−6] | 147Sm/144Nd | 143Nd/144Nd | εNd (0) |
|---|---|---|---|---|---|---|---|
| 1 | BJY-5 | uranium-polymetallic phosphorite | 18.1 | 96.9 | 0.113 | 0.511816 | −16.03 |
| 2 | BJY-4 | 21.8 | 117 | 0.1131 | 0.511792 | −16.5 | |
| 3 | BJY-3 | 22.2 | 119 | 0.1122 | 0.511773 | −16.87 | |
| 4 | BJY-2 | 20.1 | 110 | 0.1106 | 0.511548 | −21.26 |
(143Nd/144Nd) CHUR = 0.512638, (147Sm/144Nd) CHUR = 0.1967.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
MDPI and ACS Style
Li, Z.; Qin, M.; Cai, Y.; Yi, L.; Wang, W.; Wang, J.; Li, L. New Evidence of Submarine Exhalative Sedimentation in the Uranium-Polymetallic Phosphorite Deposit in Baizhuyu, Hunan, China. Minerals 2022, 12, 826. https://doi.org/10.3390/min12070826
AMA Style
Li Z, Qin M, Cai Y, Yi L, Wang W, Wang J, Li L. New Evidence of Submarine Exhalative Sedimentation in the Uranium-Polymetallic Phosphorite Deposit in Baizhuyu, Hunan, China. Minerals. 2022; 12(7):826. https://doi.org/10.3390/min12070826
Chicago/Turabian StyleLi, Zhixing, Mingkuan Qin, Yuqi Cai, Longsheng Yi, Wenquan Wang, Jian Wang, and Longlong Li. 2022. "New Evidence of Submarine Exhalative Sedimentation in the Uranium-Polymetallic Phosphorite Deposit in Baizhuyu, Hunan, China" Minerals 12, no. 7: 826. https://doi.org/10.3390/min12070826
Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.
