贵州关岭生物群的埋藏环境与古生态特点

新建并逐层描述了含关岭生物群的上三叠统小凹组。根据小凹组下段岩石学、地球化学和生物群生态特征分析，指出关岭新铺乡一带在晚三叠世时为一个三面环陆、一面可能与特提斯大洋相通的局限海湾。关岭生物群中少量完好保存的植物化石的生态特点指示该区当时具有热带、亚热带的气候特点，雨水充沛。元素地球化学特征则显示海湾中的海水可能受间歇性大量淡水注入影响而出现间歇性淡化，并导致生物原来赖以生存的海洋环境出现间歇性缺氧，而发生生物集群死亡和埋藏。

Taphonomic environment and ecological characteristics of the Guanling biota

The Upper Triassic Xiaowa Formation,bearing the Guanling biota,is established and described bed by bed on the basis of previous work and systematic measurements.Study of the petrology and geo-chemistry of the Lower Member of the Xiaowa Formation,as well as the ecological characteristics of the Guanling biota indicates that the Xinpu area of Guanling County,Guizhou Province,was a restricted gulf encircled by land on three sides and connected with the Tethyan Ocean on one side during the early-middle Canian Stage(Late Triassic).The ecological characteristics of a few well persevered plant fossils and lots of wood fossils found in the Guanling biota reveal that this area would have the tropical and subtropi-cal climatic characteristics and plenty of rainfalls during the early Late Triassic.Element geochemical charac-teristics show that seawater in the gulf may have been freshened intermittently under the influence of inter-mittent input of large amount of fresh water,so that the marine environment that organisms relied on for subsistence was intermittently anoxic or dysoxic and then there occurred mass mortality and burial of organ-isms.