摘要
产于贵州关岭县新铺乡的上三叠统小凹组底部的关岭生物群,主要由海生爬行类(鱼龙、海龙、鳍龙、盾齿龙等)、海百合、菊石、双壳、腕足、牙形刺、鱼类和植物组成,以保存完整精美、数量巨大的海生爬行类和棘皮动物海百合为标志。通过岩相和古地理分析,对关岭生物群的生活环境和演化可以得出两点结论。1关岭生物群生活在水流强度小、相对贫氧的凹向北西的陆缘海湾,离海岸最近的地方约10km。2关岭生物群发生、发展、消亡和环境的变化关系密切。关岭生物群演化经历了几个演化阶段离岸稍远的稳定碳酸盐台地环境,沉积形成竹杆坡组顶部;一次规模较大的海退,形成了竹杆坡组与小凹组岩层之间的突变;离岸较近的海水深浅变化频繁的海湾环境,沉积形成小凹组底部灰岩和含陆源碎屑灰岩互层段;离岸相对不远的比较稳定的海湾环境时期,关岭生物群就生活在这个时期;强烈动荡的海洋环境,沉积形成的是中厚—厚层的具大量滑塌、搅动构造的灰岩层,关岭生物群受突如其来的灾难的影响,迁移到其他地方生息繁衍,结束了关岭生物群在该区的生活。
The Guanling Biota occurs at the bottom of the Upper Triassic Xiaowa Formation, in Xinpu Town, Guanling County, Guizhou Province, China. Its fossils consist of marine reptiles （ichthyosaurus, thalattosaurus, sauropterygia and placodus）, crinoid, ammonite, bivalve, brachiopod, condone, fish and plants. It is marked by a lot of marine reptiles and crinoid with features intact and delicate preservation. Two conclusions are made based on analysis of their lithofacies and paleogeography. One is that the animals of the Guanling Biota lived in a place at least 10 km away from the coastline in a bay concave to the northwest with weak current and low oxygen, and the other is that the emergence, development and extinction of the Guanling Biota are closely related to environmental evolution. The evolution of the Guanling Biota includes several stages. stable carbonate platform, a little far away from the coastline, the upper part of the Zhuganpo Formation deposited; a large-scale regression, resulting in the sharp lithological change between the Zhuganpo Formation and Xiaowa Formation; a near bay with frequent change of sea level, limestones with terrigenous material at the bottom of the Xiaowa Formation formed; a relatively stable bay not far from the coastline, the Guanling Biota prospered; violent environment, medium-bedded massive limestone with slumping structure formed, and the animals of the Guanling Biota run away.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2006年第4期481-490,共10页
Acta Geologica Sinica
基金
2001年中国科学院王宽诚博士后基金项目
2001年贵州省自然科学基金项目(编号[2001]3075)
2002年中国科学院西部之光项目
国土资源部自由探索项目(编号2002415)
2004年贵州省优秀科技教育人才省长专项基金资助项目成果。
