Paleoenvironment controls on organic matter accumulation in transitional shales from the eastern Ordos Basin, China

Abstract

To investigate the paleoenvironmental controls on organic matter accumulation of Upper Paleozoic shales in the eastern Ordos Basin, China, 26 shale samples were collected from two wells drilled into the Shanxi and Taiyuan Formations. The total organic carbon (TOC) content, mineral compositions and elemental geochemistry of the samples were analyzed. Quartz (35.42%) and clay minerals (48.34%) are the dominant minerals and trace elements (Li, Cs, Cu, V, Co, and Cr) are commonly enriched in the shale samples compared to the Upper Continental Crust. C-values (ranging from 0.2 to 4.5), chemical indices of weathering (CIW) values (48.82 to 99.11), and Sr/Cu ratios (1.00 to 11.05) suggest that the paleoclimate was humid in the study area during the Late Paleozoic. Elemental redox indices (e.g., Al₂O₃/(Al₂O₃+Fe₂O₃), V/Cr, Ni/Co, V/(V+Ni) and U/Th) indicate a dysoxic to oxic paleoenvironment characterized by transitional sedimentary deposits in a continental margin setting. In addition, chemical index of alteration (CIA, ranging from 77.92% to 98.36%) and CIW (89.19% to 99.11%) values suggest that there was intense chemical weathering in the study area, while the Al₂O₃-CaO^*+Na₂O-K₂O (A-CN-K) ternary diagram demonstrates that the shales were not subjected to potassium metasomatism during diagenesis. Al₂O₃/TiO₂ and TiO₂/Zr ratios, as well as REE characteristics suggest a felsic source rocks and discount seawater as an REE source. Ce anomalies indicate an oxic environment with terrigenous input during black shale deposition, and LREE enrichment with negative Eu anomalies suggests that both shale formations were affected by detrital input rather than hydrothermal fluids. The correlation of TOC (ranging from 1.10% to 6.39%, with an average of 2.77%) with trace elemental redox indices (Sr/Cu, Sr/Ba, V/Cr, and U/Th) indicates that a warm-humid, dysoxic to oxic environment preserved much of the organic matter.

Graphical abstract

Keywords

Late Paleozoic / shale / geochemistry / paleoenvironment / eastern Ordos Basin

References

[1] Algeo T J, Maynard J B (2004). Trace-element behavior and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems. Chem Geol, 206(3–4): 289–318

[2] Arthur M A, Sageman B B (1994). Marine black shales: depositional mechanisms and environments of ancient deposits. Annu Rev Earth Planet Sci, 22(1): 499–551

[3] Bai F, Sun Y, Liu Y, Guo M (2017). Evaluation of the porous structure of Huadian oil shale during pyrolysis using multiple approaches. Fuel, 187: 1–8

[4] Bai Y, Liu Z, Sun P, Liu R, Hu X, Zhao H, Xu Y (2015). Rare earth and major element geochemistry of Eocene fine-grained sediments in oil shale- and coal-bearing layers of the Meihe Basin, Northeast China. J Asian Earth Sci, 97: 89–101

[5] Bezard R, Hébert R, Wang C, Dostal J, Dai J, Zhong H (2011). Petrology and geochemistry of the Xiugugabu ophiolitic massif, western Yarlung Zangbo suture zone, Tibet. Lithos, 125(1–2): 347–367

[6] Birk D, White J C (1991). Rare earth elements in bituminous coals and underclays of the Sydney Basin, Nova Scotia: element sites, distribution, mineralogy. Int J Coal Geol, 19(1–4): 219–251

[7] Chermak J A, Schreiber M E (2014). Mineralogy and trace element geochemistry of gas shales in the United States: environmental implications. Int J Coal Geol, 126: 32–44

[8] Dai S, Li T, Seredin V V, Ward C R, Hower J C, Zhou Y, Zhang M, Song X, Song W, Zhao C (2014). Origin of minerals and elements in the Late Permian coals, tonsteins, and host rocks of the Xinde Mine, Xuanwei, eastern Yunnan, China. Int J Coal Geol, 121: 53–78

[9] Dai S, Ren D, Chou C, Li S, Jiang Y (2006). Mineralogy and geochemistry of the No. 6 Coal (Pennsylvanian) in the Junger Coalfield, Ordos Basin, China. Int J Coal Geol, 66(4): 253–270

[10] Dai S, Seredin V V, Ward C R, Hower J C, Xing Y, Zhang W, Song W, Wang P (2015b). Enrichment of U–Se–Mo–Re–V in coals preserved within marine carbonate successions: geochemical and mineralogical data from the Late Permian Guiding Coalfield, Guizhou, China. Miner Depos, 50(2): 159–186

[11] Dai S, Yang J, Ward C R, Hower J C, Liu H, Garrison T M, French D, O’Keefe J M K (2015a). Geochemical and mineralogical evidence for a coal-hosted uranium deposit in the Yili Basin, Xinjiang, northwestern China. Ore Geol Rev, 70: 1–30

[12] Douville E, Bienvenu P, Charlou J L, Donval J P, Fouquet Y, Appriou P, Gamo T (1999). Yttrium and rare earth elements in fluids from various deep-sea hydrothermal systems. Geochim Cosmochim Acta, 63(5): 627–643

[13] Fu X, Wang J, Zeng Y, Tan F, He J (2011a). Geochemistry and origin of rare earth elements (REEs) in the Shengli River oil shale, northern Tibet, China. Chemistry, 71(1): 21–30

[14] Fu X, Wang J, Zeng Y, Tan F, Feng X (2011b). Concentration and mode of occurrence of trace elements in marine oil shale from the Bilong Co area, northern Tibet, China. Int J Coal Geol, 85(1): 112–122

[15] Gao P, Liu G, Jia C, Young A, Wang Z, Wang T, Zhang P, Wang D (2016). Redox variations and organic matter accumulation on the Yangtze carbonate platform during Late Ediacaran–Early Cambrian: constraints from petrology and geochemistry. Palaeogeogr Palaeocl Palaeoeco, 450: 91–110

[16] Hakimi M H, Abdullah W H, Sia S G, Makeen Y M (2013). Organic geochemical and petrographic characteristics of Tertiary coals in the northwest Sarawak, Malaysia: implications for palaeoenvironmental conditions and hydrocarbon generation potential. Mar Pet Geol, 48: 31–46

[17] Han S, Hu K, Cao J, Pan J, Xia F, Wu W (2015). Origin of early Cambrian black-shale-hosted barite deposits in South China: mineralogical and geochemical studies. J Asian Earth Sci, 106: 79–94

[18] Han S, Zhang J, Wang C, Tang X (2018). Elemental geochemistry of lower Silurian Longmaxi shale in southeast Sichuan Basin, South China: constraints for paleoenvironment. Geol J, 53(4): 1458–1464

[19] Hayashi K I, Fujisawa H, Holland H D, Ohmoto H (1997). Geochemistry of approximately 1.9 Ga sedimentary rocks from northeastern Labrador, Canada. Geochim Cosmochim Acta, 61(19): 4115–4137

[20] He J, Ding W, Zhang J, Li A, Zhao W, Dai P (2016). Logging identification and characteristic analysis of marine–continental transitional organic-rich shale in the Carboniferous-Permian strata, Bohai Bay Basin. Mar Pet Geol, 70: 273–293

[21] He T, Lu S, Li W, Sun D, Pan W, Zhang B, Tan Z, Ying J (2020). Paleoweathering, hydrothermal activity and organic matter enrichment during the formation of earliest Cambrian black strata in the northwest Tarim Basin, China. J Petrol Sci Eng, 189: 106987

[22] He T, Lu S, Li W, Tan Z, Zhang X (2018). Effect of salinity on source rock formation and its control on the oil content in shales in the Hetaoyuan Formation from the Biyang Depression, Nanxiang Basin, Central China. Energ Fuels, 32(6): 6698–6707

[23] Hofmann M H, Li X H, Chen J, MacKenzie L A, Hinman N W (2016). Provenance and temporal constraints of the Early Cambrian Maotianshan Shale, Yunnan Province, China. Gondwana Res, 37: 348–361

[24] Hu J, Tang S, Zhang S (2016). Investigation of pore structure and fractal characteristics of the Lower Silurian Longmaxi shales in western Hunan and Hubei Provinces in China. J Nat Gas Sci Eng, 28: 522–535

[25] Jones B, Manning D A (1994). Comparison of geochemical indices used for the interpretation of palaeoredox conditions in ancient mudstones. Chem Geol, 111(1–4): 111–129

[26] Kasanzu C, Maboko M A H, Manya S (2008). Geochemistry of fine-grained clastic sedimentary rocks of the Neoproterozoic Ikorongo Group, NE Tanzania: implications for provenance and source rock weathering. Precambrian Res, 164(3–4): 201–213

[27] Li Y, Tang D, Wu P, Niu X, Wang K, Qiao P, Wang Z (2016). Continuous unconventional natural gas accumulations of Carboniferous-Permian coal-bearing strata in the Linxing area, northeastern Ordos basin, China. J Nat Gas Sci Eng, 36: 314–327

[28] Li Y, Fan T, Zhang J, Zhang J, Wei X, Hu X, Zeng W, Fu W (2015). Geochemical changes in the Early Cambrian interval of the Yangtze Platform, South China: implications for hydrothermal influences and paleocean redox conditions. J Asian Earth Sci, 109: 100–123

[29] Li Y, Wang Z, Pan Z, Niu X, Yu Y, Meng S (2019a). Pore structure and its fractal dimensions of transitional shale: a cross section from east margin of the Ordos Basin, China. Fuel, 241: 417–431

[30] Li Y, Wang Z, Gan Q, Niu X, Xu W (2019b). Paleoenvironmental conditions and organic matter accumulation in Upper Paleozoic organic-rich rocks in the east margin of the Ordos Basin, China. Fuel, 252: 172–187

[31] Li Y, Wang Y, Wang J, Pan Z (2020a). Variation in permeability during CO₂–CH₄ displacement in coal seams: Part I—experimental insights. Fuel, 263: 116666

[32] Li Y, Yang J, Pan Z, Tong W (2020b). Nanoscale pore structure and mechanical property analysis of coal: an insight combining AFM and SEM images. Fuel, 260: 116352

[33] Ma L, Teng F Z, Jin L, Ke S, Yang W, Gu H O, Brantley S L (2015). Magnesium isotope fractionation during shale weathering in the Shale Hills Critical Zone Observatory: accumulation of light Mg isotopes in soils by clay mineral transformation. Chem Geol, 397: 37–50

[34] McLennan S M (1993). Weathering and global denudation. J Geol, 101(2): 295–303

[35] McLennan S M (2001). Relationships between the trace element composition of sedimentary rocks and upper continental crust. Geochem Geophy Geosy, 2: 2000GC000109

[36] Meng Q, Liu Z, Bruch A A, Liu R, Hu F (2012). Palaeoclimatic evolution during Eocene and its influence on oil shale mineralisation, Fushun basin, China. J Asian Earth Sci, 45: 95–105

[37] Michard A, Albarède F (1986). The REE content of some hydrothermal fluids. Chem Geol, 55(1–2): 51–60

[38] Murray R W (1994). Chemical criteria to identify the depositional environment of chert: general principles and applications. Sediment Geol, 90(3–4): 213–232

[39] Nesbitt H, Young G (1982). Early Proterozoic climates and plate motions inferred from major element chemistry of lutites. Nature, 299(5885): 715–717

[40] Nesbitt H, Young G (1984). Prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations. Geochim Cosmochim Acta, 48(7): 1523–1534

[41] Newport L P, Aplin A C, Gluyas J G, Greenwell H C, Gröcke D R (2016). Geochemical and lithological controls on a potential shale reservoir: Carboniferous Holywell Shale, Wales. Mar Pet Geol, 71: 198–210

[42] Olivarez A M, Owen R M (1991). The europium anomaly of seawater: implications for fluvial versus hydrothermal REE inputs to the oceans. Chem Geol, 92(4): 317–328

[43] Qiu X, Liu C, Mao G, Deng Y, Wang F, Wang J (2014). Late Triassic tuff intervals in the Ordos Basin, Central China: their depositional, petrographic, geochemical characteristics and regional implications. J Asian Earth Sci, 80: 148–160

[44] Qiu X, Liu C, Wang F, Deng Y, Mao G (2015). Trace and rare earth element geochemistry of the Upper Triassic mudstones in the southern Ordos Basin, Central China. Geol J, 50(4): 399–413

[45] Sarki Yandoka B M, Abdullah W H, Abubakar M B, Hakimi M H, Adegoke A K (2015). Geochemistry of the Cretaceous coals from Lamja Formation, Yola Sub-basin, Northern Benue Trough, NE Nigeria: implications for paleoenvironment, paleoclimate and tectonic setting. J Afr Earth Sci, 104: 56–70

[46] Stepanova V A, Pokrovsky O S, Viers J, Mironycheva-Tokareva N P, Kosykh N P, Vishnyakova E K (2015). Elemental composition of peat profiles in western Siberia: effect of the micro-landscape, latitude position and permafrost coverage. Appl Geochem, 53: 53–70

[47] Sun Y, Zhao C, Qin S, Xiao L, Li Z, Lin M (2016). Occurrence of some valuable elements in the unique ‘high-aluminium coals’ from the Jungar coalfield, China. Ore Geol Rev, 72: 659–668

[48] Tang L, Song Y, Jiang Z, Jiang S, Li Q (2019). Pore structure and fractal characteristics of distinct thermally mature shales. Energ Fuels, 33(6): 5116–5128

[49] Tao S, Shan Y, Tang D, Xu H, Li S, Cui Y (2016). Mineralogy, major and trace element geochemistry of Shichanggou oil shales, Jimusaer, Southern Junggar Basin, China: implications for provenance, palaeoenvironment and tectonic setting. J Petrol Sci Eng, 146: 432–445

[50] Tribovillard N, Algeo T J, Lyons T, Riboulleau A (2006). Trace metals as paleoredox and paleoproductivity proxies: an update. Chem Geol, 232(1–2): 12–32

[51] Udchachon M, Thassanapak H, Feng Q, Burrett C (2017). Palaeoenvironmental implications of geochemistry and radiolarians from Upper Devonian chert/shale sequences of the Truong Son fold belt, Laos. Geol J, 52(1): 154–173

[52] Vosoughi Moradi A, Sarı A, Akkaya P (2016a). Geochemistry of the Miocene oil shale (Hançili Formation) in the Çankırı-Çorum Basin, Central Turkey: implications for Paleoclimate conditions, source–area weathering, provenance and tectonic setting. Sediment Geol, 341: 289–303

[53] Vosoughi Moradi A, Sarı A, Akkaya P (2016b). Paleoredox reconstruction of bituminous shales from the Miocene Hançili Formation, Çankırı-Çorum Basin, Turkey: evaluating the role of anoxia in accumulation of organic-rich shales. Mar Pet Geol, 78: 136–150

[54] Wang J, Chen D, Wang D A N, Yan D, Zhou X, Wang Q (2012). Petrology and geochemistry of chert on the marginal zone of Yangtze Platform, western Hunan, South China, during the Ediacaran-Cambrian transition. Sedimentology, 59(3): 809–829

[55] Wang S, Dong D, Wang Y, Li X, Huang J, Guan Q (2016). Sedimentary geochemical proxies for paleoenvironment interpretation of organic-rich shale: a case study of the Lower Silurian Longmaxi Formation, Southern Sichuan Basin, China. J Nat Gas Sci Eng, 28: 691–699

[56] Wang S, Zou C, Dong D, Wang Y, Li X, Huang J, Guan Q (2015). Multiple controls on the paleoenvironment of the Early Cambrian marine black shales in the Sichuan Basin, SW China: geochemical and organic carbon isotopic evidence. Mar Pet Geol, 66: 660–672

[57] Xiao X M, Zhao B Q, Thu Z L, Song Z G, Wilkins R W T (2005). Upper Paleozoic petroleum system, Ordos Basin, China. Mar Pet Geol, 22(8): 945–963

[58] Xiong F, Jiang Z, Huang H, Wen M, Moortgat J (2019). Mineralogy and gas content of Upper Paleozoic Shanxi and Benxi Shale Formations in the Ordos Basin. Energy Fuels, 33(2): 1061–1068

[59] Xu G, Hannah J L, Bingen B, Georgiev S, Stein H J (2012). Digestion methods for trace element measurements in shales: paleoredox proxies examined. Chem Geol, 324-325: 132–147

[60] Xu H, Tang D, Tang S, Zhang W, Meng Y, Gao L, Xie S, Zhao J (2015). Geologic and hydrological controls on coal reservoir water production in marine coal-bearing strata: a case study of the Carboniferous Taiyuan Formation in the Liulin area, eastern Ordos Basin, China. Mar Pet Geol, 59: 517–526

[61] Yang C, Xiong Y, Zhang J, Liu Y, Chen C (2019). Comprehensive understanding of OM-hosted pores in transitional shale: a case study of Permian Longtan Shale in South China based on organic petrographic analysis, gas adsorption, and X-ray diffraction measurements. Energy Fuels, 33(9): 8055–8064

[62] Yang H, Fu J, Wei X, Liu X (2008). Sulige field in the Ordos Basin: geological setting, field discovery and tight gas reservoirs. Mar Pet Geol, 25(4–5): 387–400

[63] Yang N, Tang S, Zhang S, Chen Y (2015). Mineralogical and geochemical compositions of the No. 5 coal in chuancaogedan mine, Junger Coalfield, China. Minerals (Basel), 5(4): 788–800

[64] Yang N, Tang S, Zhang S, Chen Y (2016). Modes of occurrence and abundance of trace elements in Pennsylvanian coals from the Pingshuo Mine, Ningwu Coalfield, Shanxi Province, China. Minerals (Basel), 6(2): 40

[65] Zhang J, Fan T, Algeo T J, Li Y, Zhang J (2016). Paleo-marine environments of the Early Cambrian Yangtze Platform. Palaeogeogr Palaeocl Palaeoeco, 443: 66–79

[66] Zhang S, Tang S, Tang D, Pan Z, Yang F (2010). The characteristics of coal reservoir pores and coal facies in Liulin district, Hedong coal field of China. Int J Coal Geol, 81(2): 117–127

[67] Zhao J, Xu H, Tang D, Mathews J P, Li S, Tao S (2016a). Coal seam porosity and fracture heterogeneity of macrolithotypes in the Hancheng Block, eastern margin, Ordos Basin, China. Int J Coal Geol, 159: 18–29

[68] Zhao J, Tang D, Xu H, Li Y, Li S, Tao S, Lin W, Liu Z (2016b). Characteristic of in situ stress and its control on the coalbed methane reservoir permeability in the eastern margin of the Ordos Basin, China. Rock Mech Rock Eng, 49(8): 3307–3322

Acknowledgements

The research was supported by National Natural Science Foundation of China (Grant No. 41872178).

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