Quantitative palaeogeographical reconstruction of the North China Block during the Carboniferous and Permian transition: Implications for coal accumulation and source rock development

The Impact of Marine Influence on the Hydrocarbon Generation Potential and Process of Upper Paleozoic Coal in the Eastern Ordos Basin, China: Implications for Unconventional Gas Exploration of Coal Measures

“…Coal samples from the Benxi Formation (1.98% TS), Taiyuan Formation (1.38% TS), and Shanxi Formation (0.46% TS) display a decreasing sulfur trend (Table ). This is in accordance with the sedimentary background of the coal measures. , The Upper Paleozoic coal deposition in the Ordos Basin predominantly occurred in tidal delta plain, tidal flat, and fluvial delta plain. , The organic sulfur content in macerals in coals formed in different depositional environments decreases in the order of tidal delta plain > tidal flat > fluvial delta plain . This suggests that the sulfur content of coals increases due to marine intrusion.…”

“…A more promising scenario emerges in the Panhe block of the southern Qinshui Basin, where coal seams possess thermal maturities ranging from 3.4 to 4.0% . Importantly, the Upper Paleozoic coal seams in both the Qinshui and Ordos Basins share a similar sedimentary background . Consequently, we can anticipate that marine-influenced coal seams (Taiyuan and Benxi Formations) within the Panhe block would hold greater potential for late-stage hydrocarbon gas generation compared to the nonmarine Shanxi Formation coals.…”

“…Located in central China on the western edge of the North China Craton, the Ordos Basin covers a vast area of 25 × 10 4 km 26 It is a large craton basin with a variety of tectonic systems and sedimentary types. The Ordos Basin can be divided into six tectonic units: the Western thrust fault belt and Tianhuan depression in the west, the Jinxi fold belt in the east, the Yishan slope in the middle, the Yimeng uplift in the north, and the Weibei uplift in the south 32 (Figure 1).…”

“…Coinciding with the deposition of the Carboniferous Benxi Formation, several factors, including basement subsidence, global warming, and the retreat of Gondwanan glaciers, facilitated a large-scale transgression. 26 This resulted in a barrier island-coast depositional environment within the eastern Ordos basin. The Permian Taiyuan Formation witnessed a continued rise in the seawater influence.…”

“…26,27 The deposition of the Shanxi Formation witnessed the emergence of a continental lake-delta sedimentary system within the basin. 26 Peat deposition predominantly occurred in terrestrial settings, transitional settings, and marine settings like tidal flats. Notably, the coal-forming conditions were closely linked to significant and frequent eustatic fluctuations.…”