内蒙古林西县及邻区晚二叠世生物礁和环境意义

发布时间：2018-04-06 02:05

本文选题：生物礁　切入点：造礁环境　出处：《中国科学:地球科学》2016年07期

【摘要】：在内蒙林西县及邻区首次观察到大量晚二叠世台缘礁和丘状礁.初步研究证实,兴-蒙地区当时为开放海槽环境.本文首先分析林西官地林西组四、五段沉积相和相序叠置,再造晚二叠世晚期林西-九台裂陷带的稳定沉降-缓慢抬升-迅速闭合过程;并且利用多门类化石的属种延续和丰度分布,确定含生物礁地层的地质时代和划分对比,为生物礁研究奠定基础.然后详细研究多类造礁生物,即海绵、苔藓虫和钙藻等的形态功能和造礁机制,恢复各门类的生态条件和造礁环境,划分出6个造礁生物组合.综合沉积相、地层和生物古生态研究成果,识别出晚二叠世晚期2类陆棚边缘,即丘状礁缓坡陆棚边缘和障壁礁陡坡陆棚边缘.从而论证生物礁的线状分布标志中朝板块北缘及兴蒙-海槽内林西-九台裂陷带在晚二叠世末期闭合.
[Abstract]:For the first time, a large number of late Permian platform margin reefs and hilly reefs were observed in Linxi County, Inner Mongolia.Preliminary study confirmed that the Xing-Mongolia area was an open trough environment at that time.This paper first analyzes the sedimentary facies and facies sequence superposition of the fourth and fifth member of Guandi Linxi formation, and reconstructs the stable subsidence, slow uplift and rapid closure process of the late late Permian Linxi-Jiutai rift belt.The geological age and classification and correlation of reef bearing strata are determined by using the genus and species continuation and abundance distribution of multi-family fossils, which lays a foundation for the study of reef.Then the morphological function and reef-forming mechanism of many kinds of reef organisms, I. E. sponges, bryophytes and calcium algae, were studied in detail, and the ecological conditions and reef-making environment of each group were restored, and six reef assemblages were divided.Based on the results of sedimentary facies, stratigraphy and biopaleoecology, two types of shelf margins were identified in the late late late Permian, I. E. the margin of the shelf on the gentle slope of the hilly reef and the edge of the shelf on the steep slope of the barrier reef.It is demonstrated that the linear distribution of the reef marks the northern margin of the Sino-Korean plate and the closure of the Linxi-Jiutai rift zone in the Xingmen-trough at the end of the late Permian.
【作者单位】：中国地质科学院地质研究所;中国地质科学院矿产资源研究所;中国地质科学院科技处;
【基金】：国家自然科学基金项目(批准号:41472027) 中国地质调查项目(编号:1212011120927)资助
【分类号】：P534.46

【参考文献】