Depositional facies and characteristic of trace fossils in the upper Triassic Taishanmiao Formation of Liushan basin, Henan Province

Based on the research of sedimentology and ichnology, the upper Triassic Taishanmiao Formation in Liushan basin of Henan province is considered to be a set of terrestrial fluvial-lacustrine and coal-bearing depositional system under a warm and moist climate conditions.During the late Triassic, the environmental evolution of this basin was a process as fluvial-lucustrine and swamp-lake shore and shallow lacustrine-deep lacustrine-lake shore and shallow lacustrine-semi-deep lacustrine-lake shore and shallow lacustrine.Therefore, the basin went through such two evolutionary stages of sedimentary cycles as "subside-rise-subside-rise".In this work, 4 ichnogenera and 4 ichnospecies, such as Beaconites coronus, Cochlichnus surpuliformis, Palaeophycus tubularis and Planolites montanus, have been identified in the Taishanmiao Formation.This paper especially discusses the developing features of the Beaconites coronus in different micro-facies, and speculates that the trace-makers of Beaconites adapt best to the shore lake environment.The research result provides the theoretical support to not only the compilation of late Triassic lithofacies palaeogeography map but also the evaluation and development of potential mineral resources in this area.