Late Paleozoic Accumulation of Coal-Bearing Successions in the Wuhai Coalfield, Western North China: Back-Arc Basin Response to Southward Subduction of the Paleo-Asian Ocean

The Late Paleozoic is an important epoch of coal-bed accumulation in the North China, particularly its western segment, where a world-class coal field has been found and exploited for three decades. Coal-bearing layers recorded rapid Carboniferous to Early Permian sea-level rise that led evolution shallow marine tidal flat basin, followed by regression resulted formation deltaic facies. However, little attention paid tectonic factors assisted processes, which have demonstrated worldwide be pivotal. In this study, we evaluate significant influence southward subduction middle segment Paleo-Asian Ocean (PAO) during deposition coal-bearing neritic successions China Block (NCB). We pinpoint direct link between basin-filling northwestern Ordos Basin progressive uplift Inner Mongolia continental arc triggered south-dipping Solonker ocean plate. Sedimentary facies variation paleocurrent reconstruction indicate sedimentary routing from north northeast. petrology detrital zircon geochronology sampled sandstones evolving provenances dominated cratonic basement mixed orogen arc. samples are generally quartz arenites contain large number Archean Paleoproterozoic zircons with small amounts pluton components, indicating sediment supply NCB Precambrian basement. contrast, youngest sample Shanxi Formation sub-litharenite, age spectrum characterized dominance ca. 450 270 Ma ages, indicative high influx detritus. This shift sandstone petrology, distribution, depositional setting allows us shoaling mountain building unroofing arc, enhances our understanding both PAO NCB.