Origin of silica, paleoenvironment, and organic matter enrichment in the Lower Paleozoic Niutitang and Longmaxi formations of the northwestern Upper Yangtze Plate: Significance for hydrocarbon exploration

Li, Delu; Li, Rongxi; Tan, Chengqian; Zhao, Dong Liang; Xue, Teng; Zhao, Bangsheng; Khaled, Ahmed; Liu, Futian; Xu, Feng

doi:10.1016/j.marpetgeo.2019.02.025

Cited by 44 publications

(16 citation statements)

References 54 publications

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“…Previous studies have shown that the silica content is positively correlated with the TOC content for the Early Cambrian Niutitang black shale, indicating the existence of Si bio in this shale [17,76,77]. The fraction of the Si bio content in the shale samples can be estimated as follows [78]:…”

Section: Paleoproductivitymentioning

confidence: 96%

Depositional Environment and Organic Matter Enrichment of Early Cambrian Niutitang Black Shales in the Upper Yangtze Region, China

et al. 2022

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Natural gas generation is the result of organic matter degradation under the effects of biodegradation and thermal degradation. Early Cambrian black shales in the Upper Yangtze Region are rich in organic matter and have shown great shale gas potentiality in recent years. Nevertheless, the enrichment mechanism and distribution of organic matter in these black shales between different sedimentary settings, such as intra-platform basin, slope, and deep basin, are still poorly understood. In this paper, based mainly on elemental geochemistry, a comprehensive study of the marine redox conditions, primary productivity, sedimentation rate, terrigenous input, hydrothermal activity, and water mass restrictions was conducted on the Early Cambrian Niutitang black shale in the Upper Yangtze Region. Our data showed that an intra-platform basin received a higher terrigenous input and that it deposited under more restricted conditions than the slope and deep basin settings. The primary productivity in the slope and deep basin settings was higher than that in the intra-platform basin setting. In the intra-platform basin, the productivity increased from its inner part to its margin. For the slope and deep basin settings, the high paleoproductivity generated large amounts of organic matter and its preservation was synergistically affected by the redox conditions. In contrast to the slope and deep basin, the preservation of organic matter in the inner part of the intra-platform basin was mainly controlled by redox conditions because the paleoproductivity in it was much lower than in the slope and deep basin settings. The intra-platform basin margin was the most favorable area for accumulating organic matter.

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Section: Paleoproductivitymentioning

confidence: 96%

Depositional Environment and Organic Matter Enrichment of Early Cambrian Niutitang Black Shales in the Upper Yangtze Region, China

et al. 2022

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“…It is obvious that the shale lithofacies in the geomorphic highlands had high silicate contents, while these were low in the low-lying areas. According to previous research, the silica in the shales of the Longmaxi Formation mainly were derived from silica radiolarians, which mainly live in deep-water areas (Zhao et al, 2016b;Lu et al, 2018;Yang et al, 2018;Dong et al, 2019;Li et al, 2019;Liu et al, 2019;Yang et al, 2019;, 2020; Guan et al, 2021;Xu et al, 2021). According to this conclusion, the shale lithofacies should be rich in siliceous content in the depressions (low-lying areas) but be lacking siliceous content in geomorphic highlands.…”

Section: Paleogeomorphologymentioning

confidence: 98%

Development Characteristics of Shale Lithofacies in the Longmaxi Formation and their Main Controlling Factors in the Changning Area, South Sichuan Basin, SW China

et al. 2021

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Based on core observations, thin sections, X-ray diffraction (XRD), and seismic data, the lithofacies types in the organic-rich Longmaxi shale (Lower Silurian) in the Changning area of the southern Sichuan Basin were identified. The factors controlling the spatial variations in the shale lithofacies and the influences of the shale lithofacies on shale gas development were also analyzed. Results indicate that there are seven main types of shale lithofacies in the Long11 sub-member of the Longmaxi Formation, including siliceous shale (S-1), mixed siliceous shale (S-2), carbonate-rich siliceous shale (S-3), clay-rich siliceous shale (S-4), carbonate/siliceous shale (M-1), mixed shale (M-2), and argillaceous/siliceous shale (M-4). A vertical transition from the carbonate shale association + mixed shale association at the bottom of the sub-member to a siliceous shale association and mixed shale association + siliceous shale at the top generally appears in the Long11 sub-member. The shale lithofacies of the Long11 sub-member also laterally change from the central depression (low-lying area) to the geomorphic highland in the east and west parts of the Changning area. The spatial variations in shale lithofacies in the Long11 sub-member of the Changning area were mainly controlled by palaeogeomorphology and relative sea level. The geomorphic highland area is dominated by carbonate-rich siliceous shale and mixed siliceous shale, but the depression (low-lying area) is mainly dominated by mixed siliceous shale and argillaceous/carbonate shale.

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“…Chemical index of alteration (CIA) is commonly utilized to analyze the paleoclimate (Wedepohl 1971;Nesbitt and Young 1982;McLennan 1993;Ross and Bustin 2009a, b); the ratio of content of SiO 2 and Al 2 O 3 (SiO 2 /Al 2 O 3 ), the ratio of content of MnO and TiO 2 (MnO/TiO 2 ) and the ratio of content of yttrium and holmium (Y/Ho) are used to indicate the amount of the detrital influx (Ryuichi et al 1982;Webb and Kamber 2000); the ratio of content of vanadium and (vanadium plus nickel) (V/(V + Ni)), the ratio of content of vanadium and chromium (V/Cr), the ratio of content of nickel and cobalt (Ni/Co), EF Mo , EF U , EF V , EF Ni , the ratio of content of uranium and thorium (U/Th) and the ratio of content of cuprum and zincum (Cu/Zn) could indicate the redox environment of water (Algeo and Maynard 2004;Ross and Bustin 2009b;Pi et al 2014;Zhu et al 2018), and the ratio of content of phosphorus and titanium (P/Ti) and ratio of content of barium and aluminum (Ba/Al) could present the paleoproductivity (Dean et al 1997;Algeo et al 2011;Liu et al 2018). Currently, the accumulation characteristics of organic matter with the geochemical method for Niutitang Formation shale in China mainly focus in south of Yangtze platform (Liu et al 2015(Liu et al , 2016Xia et al 2015;Wu et al 2017;Zhou et al 2017Zhou et al , 2019Li et al , 2019Zhang et al 2018;Ma et al 2019;Awan et al 2020). The lithofacies of Niutitang Formation shale in South China could be divided into five types, including organic matter-rich siliceous shale, silty-siliceous shale, argillaceous shale, calcareous shale and silty-siliceous mixed shale (Yang et al 2016;Wu et al 2017).…”

Section: Introductionmentioning

confidence: 99%

The accumulation model of organic matters for the Niutitang Formation shale and its control on the pore structure: a case study from Northern Guizhou

Gao

Wang

et al. 2022

J Petrol Explor Prod Technol

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Shale gas reservoir is a fine-grained sedimentary rock with component of clastic particles and organic matters, and the accumulation of the organic matters would determine the effective development of shale gas. The paleoclimate, detrital influx, redox of the water and paleoproductivity are effective geochemical indicators that could help to find the favorable shale gas reservoir stratum. In this study, the shale samples collected from Niutitang Formation (Northern Guizhou, China) were launched the measurements of the content of major elements and trace elements, and the characteristics of geochemical indicators were analyzed, which can be used to discuss the accumulation model of organic matters. Besides, the pore structure of shale sample controlled by the enrichment of organic matters is also discussed. The paleoclimate is dominant cold and dry, and it changes to warm and humid at the later Niutitang period, and the detrital influx also increased at the later Niutitang period; the water environment of Niutitang Formation shale presents as reductive, and the paleoproductivity of the Niutitang Formation shale is commonly high. The enrichment of organic matters in the Niutitang Formation is dominantly controlled by the redox of the water, while the hydrothermal activity and the paleoproductivity lead to the difference enrichment of organic matters in the Niutitang Formation shale. The accumulation model of organic matters also influences the characteristics of pore structure from the Niutitang Formation shale, and the pore structure could be divided into two types. The shale with high content of organic matters also features high content of quartz and pyrite, and these minerals contribute to the preservation of pore space in the shale, while that of the clay minerals is contrary. The high content of organic matters and preferable pore characteristics indicate the Niutitang Formation favors the development of shale gas, especially that for the lower Niutitang Formation.

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Origin of silica, paleoenvironment, and organic matter enrichment in the Lower Paleozoic Niutitang and Longmaxi formations of the northwestern Upper Yangtze Plate: Significance for hydrocarbon exploration

Cited by 44 publications

References 54 publications

Depositional Environment and Organic Matter Enrichment of Early Cambrian Niutitang Black Shales in the Upper Yangtze Region, China

Depositional Environment and Organic Matter Enrichment of Early Cambrian Niutitang Black Shales in the Upper Yangtze Region, China

Development Characteristics of Shale Lithofacies in the Longmaxi Formation and their Main Controlling Factors in the Changning Area, South Sichuan Basin, SW China

The accumulation model of organic matters for the Niutitang Formation shale and its control on the pore structure: a case study from Northern Guizhou

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