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在对露头及钻孔剖面沉积特征研究的基础上,建立了华南地区晚三叠世含煤岩系层序地层格架,恢复了基于三级层序的岩相古地理,并分析了聚煤规律。根据岩相特征及岩相组合类型,在区内晚三叠世含煤地层中识别出陆相和海陆过渡相两大沉积类型,并可进一步识别出冲积扇、河流(包括辫状河和曲流河)、三角洲、湖泊、潮坪—潟湖、滨海平原和滨浅海等7种沉积类型。陆相沉积主要发育在上扬子地区的四川盆地;海陆过渡相沉积主要发育在东南部湘赣粤滨浅海。在晚三叠世含煤岩系中识别出区域性不整合面和构造应力转换面、砂砾岩体底部冲刷面和岩性突变面等类型的层序界面,将含煤岩系划分为5个三级层序。以三级层序为古地理作图单元,恢复了研究区的古地理格局。由煤层厚度与岩相古地理平面展布规律可知,最有利的成煤环境为三角洲沉积体系,其次为河流、潮坪—潟湖沉积体系,聚煤中心主要分部在四川盆地的乐威煤田以及华蓥山煤田、湘赣粤滨浅海地区的湘东南至赣西萍乡一带。
Based on the study of sedimentary characteristics of outcrop and borehole profiles, the sequence stratigraphic framework of late Triassic coal measures in southern China was established and the lithofacies palaeogeography based on the third-order sequence was restored. law. According to lithofacies characteristics and lithofacies assemblages, two sedimentary types of continental facies and sea-land transitional facies are identified in the Late Triassic coal-bearing strata in the area, and alluvial fans, rivers (including braided rivers and meanders River), delta, lake, tidal flat - lagoon, coastal plain and coastal shallow sea and other seven kinds of sedimentary types. The continental deposition mainly develops in the Sichuan Basin in the Upper Yangtze region. The transitional facies sediments mainly develop in the shallow sea of Guangdong, Jiangxi and Guangdong in the southeast. In Late Triassic coal-bearing rock series, the regional unconformity, tectonic stress transformation surface, the bottom scouring surface of lithic conglomerate body and the lithologic catastrophic surface are identified, and the coal-bearing rock series are divided into five Three-level sequence. Taking the third-order sequence as palaeogeographic mapping unit, the paleogeographic pattern of the study area was restored. Judging from the thickness of coal seam and the distribution pattern of lithofacies palaeogeography, the most favorable coal-forming environment is deltaic sedimentary system, followed by river and tidal flat-lagoon sedimentary system. The main coal accumulation center is in Lewei coalfield in Sichuan Basin and Huayingshan coalfields, Hunan, Guangdong, Guangdong and Hunan shallow coastal areas in the southeastern Hunan Pingxiang area.