Source-rock evaluation and depositional environment of black shales in the Triassic Yanchang Formation, southern Ordos Basin, north-central China

Fluid inclusions in buried quartz of the Yanchang sandstone in the Jiyuan area, Ordos Basin, China: Implications for basin evolution and petroleum accumulation

“…The higher temperature will increase the chemical kinetics of quartz dissolution; however, the concentration of SiO 4− iron has an opposite function (Dove, 1994; Ganor et al., 2005). The pH of the pore fluid may be decreased by the hydrocarbon generated in Chang 7 Member and migrated into the adjacent members (Chen et al., 2017; Cui et al., 2019; He et al., 2019), which may have a potential advantage for quartz precipitation rather than dissolution. The rate of the quartz precipitation kept in a relatively low magnitude since a high rate of production can create amorphous silica (Ganor et al., 2005; Rimstidt and Barnes, 1980).…”

“…Dashed lines show isotherms, and black arrow show inferred burial history of sandstones with quartz cement; mean salinity is grayscale coded. He et al, 2019), which may have a potential advantage for quartz precipitation rather than dissolution. The rate of the quartz precipitation kept in a relatively low magnitude since a high rate of production can create amorphous silica (Ganor et al, 2005;Rimstidt and Barnes, 1980).…”

Characteristics of Organic Macerals and Their Influence on Hydrocarbon Generation and Storage: A Case Study of Continental Shale of the Yanchang Formation from the Ordos Basin, China

“…It is bounded by the Yellow River fault to the north, the Weihe River north margin fault to the south, Liupan Mountain and Yinchuan Basin to the west, and the Lishi fault zone with the Lvliang uplift to the east. The basin has experienced a series of complex tectonic movements such as Lvliang, Caledonian, Indosinian, and Yanshan, forming the geological features of the wide and gentle east and narrow west, the well-developed peripheral faults, and the simple structure in the basin [10,11]. Based on the current structural morphology and basin evolution history, the basin can be divided into six tectonic units: the Yimeng uplift in the north, the Weibei uplift in the south, the western edge thrust belt in the west, the Jinxi folding belt in the east, and the Tianhuan depression and Yishan slope in the central region (Figure 1(a)) [12,13].…”

The petrological characteristics and significance of organic-rich shale in the Chang 7 member of the Yanchang Formation, south margin of the Ordos basin, central China

“…The organic-rich shale in the Chang 7 member is the most important source rock in the Mesozoic in the Ordos basin (Yang and Zhang 2005). In order to explore the controlling factors of high-quality source rock, countless studies have already been reported (Zhang et al 2008;Yang et al 2010;Er et al 2015;Sun et al 2015;Ma et al 2016;Li et al 2017;Wang et al 2017;Zhang et al 2017b;He et al 2019).…”