西南地区晚古生代深水生物相初探

Late paleozoic Deep Water Biofacies of SW China

西南地区晚古生代时位于华南陆板块的南部被动大陆边缘及陆内。自早泥盆世中晚期开始发生裂陷运动，在滇东、黔南和广西地区发生沿北西向为主，北东向为次的拉张裂陷沉降，最终形成由狭长的台问海槽和弧立碳酸盐台地相间排列的古地貌格局。由于浊流的发育、洋流作用，使深水海槽内海水局部混和充氧，各海槽内海水不完全停滞，不同于黑海式全封闭的阻隔式盆地。不同深度的海槽内具有不同的古生物组合，从浅到深，可归入充氧生物相，充氧──贫氧生物相，贫氧──厌氧生物相及厌氧生物相．

During the Late paleozoic, SW China was located at the passive continental margin of South China plate. From Middle to Late Devonian,a series of NW and NE rift(with the dominant orientation of NW)occurred to East Yunnan, South Guizhou and the whole Guangxi province,thus forming grabens and horsts. This topographic feature then developed into interplatform rough and isolated platform framework. Generally,tLe deep water environment of this area can be influenced by gravity flow and is much different from the modern Black Sea Models. According to the organism feature in different troughs,integrated with the nature of sediments and sedimentary strustures, several biofacies can be identified. Generally, aerobicbiofacies, aerobic-dysaerobic biofacies,dysaerobic-anaerobic biofacies and anaerobic biofacies belong to the platform margin environment, sub-shallow water interplatform trough, subdeep water interplatform trough and inherited deep water interplatform trough respectively.