Preservation of organic matter in shale linked to bacterial sulfate reduction (BSR) and volcanic activity under marine and lacustrine depositional environments

Organic-rich formation and hydrocarbon enrichment of lacustrine shale strata: A case study of Chang 7 Member

“…Volcanic ac-tivity is a potential geological force that can lead to global climate change and the extinction of biological populations (Rampino and Stothers, 1988;Olsen, 1999;Wignall, 2001;Lai et al, 2010), which affect both the enrichment and preservation of organic matter. The formation of organic-rich shale and volcanic activity correlate (Lee et al, 2018;Liu et al, 2021).…”

“…In this process, not only organic components play an important role, but also inorganic components have a crucial influence on the formation of organic matter and generation of oil and gas, e.g., water, clay minerals and transitional metal elements can be used as reactants or catalysts (Liu et al, 2019). Previous studies have shown that major shale formations are generally associated with volcanic ash layers (Liu et al, 2021), such as the Upper Devonian-Lower Carboniferous Bakken Formation in the Williston Basin (Dennison and Textoris, 1970), the Middle Devonian Marcellus Formation in the Appalachian Basin (Hayward, 2012), the Upper Cretaceous Eagle Ford Formation in Gulf Coast Basin (Robison, 1997;Duggen et al, 2007;Lee et al, 2018), the Devonian-Carboniferous Bazhenov Formation in Western Siberia, Russia (Shaldybin et al, 2019;Liang et al, 2020), the Jurassic Vaca Muerta Formation in Neuquen Basin, Argentina (Kietzmann et al, 2014), etc. In the Mesozoic and Cenozoic terrigenous petroliferous basins in China, organic-rich shale is also generally accompanied by volcanic activity (Zhao and Liu, 2016), such as the Qingshankou Formation (Gao et al, 2008;Lee et al, 2018) and Yingcheng Formation (Shan et al, 2013) in the Songliao Basin, Shahejie Formation in the Bohai Bay Basin (Du et al, 2014), Yanchang Formation in the Ordos Basin (Qiu et al, 2009;Zhang et al, 2009), Hargau (Li et al, 2010) and Lucaogou (Wu et al, 2012) formations in the Santanghu Basin, and Longmaxi Formation in the Sichuan Basin (Zhao et al, 2015).…”

“…The Chang 7 shale in the Ordos Basin generally contains multiple layers of tuff, indicating that the shale deposition period was accompanied by strong volcanic activity Yuan et al, 2019;Liu et al, 2021). The higher the number of tuff layers is, the greater is the thickness of the organic-rich shale.…”

Mineralogy and Pore Structure of Marine–Continental Transitional Shale: A Case Study of the Upper Carboniferous Keluke Formation in the Eastern Qaidam Basin, China

“…These shales are classified into three types based on origins, including marine shales, marine-continental transitional shales, and continental shales (Zou et al, 2019;Dong et al, 2021). Significant attention has been attracted by marine and continental shales in recent years, where considerable progress has been achieved (Curtis, 2002;Dai et al, 2016;Sweere et al, 2016;Li et al, 2017;Zou et al, 2019;Liu et al, 2021). Comparatively, marine-continental transitional shale is poorly investigated, which requires further and comprehensive study (Chalmers et al, 2012;Zhang et al, 2021).…”

湖相泥页岩层系富有机质形成与烃类富集——以长<bold>7</bold>为例

“…研究表明，国内外主要页岩层系普遍伴生火山灰层(Liu et al, 2021)，如美国 Williston 盆地上泥盆-下石炭统 Bakken 组(Dennison and Textoris, 1970)、 Appalachian 盆地中泥盆统 Marcellus 组(Hayward, 2012)、Gulf Coast 盆地上白垩统 Eagle Ford 组(Robison, 1997; Duggen et al, 2007; Lee et al, 2018)，俄罗斯西西伯利亚的泥盆-石炭系 Bazhenov 组(Shaldybin et al, 2019; Liang et al, 2020)， 阿根廷 Neuquen 盆地 侏罗系 Vaca Muerta 组(Kietzmann et al, 2014)等。在国内中新生代陆相含油气盆地…”