河南留山盆地太山庙组沉积相及遗迹化石特征

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

采用沉积学和遗迹学的理论及分析方法,研究了河南留山盆地上三叠统太山庙组的沉积环境。结果显示:该组为一套温暖潮湿气候条件下的河流-湖泊相含煤沉积,整个沉积经历了河流相-湖沼相-滨、浅湖相-深湖相-滨、浅湖相-半深湖相-滨、浅湖相的演化过程,显示该盆地经历了"下降-抬升-下降-抬升"的构造旋回演化过程。在该套地层中已识别出遗迹化石的4个属和4个种,包括Beaconites coronus,Cochlichnus surpuliformis,Palaeophycus tubularis和Planolites montanus等,并详细讨论了该遗迹群落中Beaconites coronus在不同微相中的发育特征,推测其造迹生物最适宜的生境是滨湖环境。该项研究成果可为本区晚三叠世岩相古地理图的编制,进而为矿产资源评价与开发提供理论依据。

Based on the research of sedimentology and ichnology,the upper Triassic Taishanmiao Formation in Li-ushan basin of Henan province is considered to be a set of terrestrial fluvial—lacustrine and coal-bearing deposi-tional 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 poten-tial mineral resources in this area.