摘要
义县组是热河生物群最繁盛的层位,它承载了热河生物群演化的重要信息,开展义县组沉积环境的深入研究是认识和恢复热河生物群生活环境的有效途径。辽西地区义县组中夹有多层碳酸盐岩沉积层,所含沉积环境信息丰富。通过碳酸盐岩的研究,获取碎屑岩中丢失的环境信息,并与碎屑岩沉积层的研究相结合,为恢复辽西地区义县期热河生物群的古地理、古气候和古生态提供科学的依据。经野外及室内研究共识别出9种碳酸盐岩石类型,并结合沉积学标志进行了环境分析。野外工作表明辽西地区义县组碳酸盐岩夹层的发育向盆地的南侧有层数增多碳酸盐含量增加的趋势。辽西地区在义县期主要以滨浅湖环境为主,碳酸盐岩主要沉积在微咸—咸水的洪泛平原储水洼地和滨浅湖沉积环境中。接受碳酸盐岩沉积时气候相对干热,湖泊水文状况趋于封闭,火山活动频繁,古湖泊水体补给量小于蒸发量。
The Yixian Formation is the most important bed for Jehol Biota.A lot of fossils preserved well of Jehol Biota were found in the Yixian Formation which recorded the important information of the Jehol Biota evolution.In order to understand and rebuild the living environment of the Jehol Biota,it is necessary to carry out further sedimentary environment studies of Yixian Formation.The abundant informations of sedimentary environment were recorded in several carbonate interlayers in the Yixian Formation of western Liaoning.Through the studies of the carbonates,the lost environmental information of the clastic rock can be obtained.The studies of carbonate and clastic rock provide scientific evidence for rebuilding the palaeoclimate,palaeogeography and palaeoecology of the Yixian Jehol Biota of western Liaoning.Eight lithotypes of carbonates have been identified by studies in the field and laboratory.The environmental analysis has been done by studying the sedimentary characteristics of the carbonate.The field works indicate that the development of the carbonate interlayers has the tendency of increase in terms of the layers and carbonate content to the southern direction of the basin.The palaeoenvironment of the western Liaoning was dominated by shore-shallow lacustrine facies in Yixian period,and the carbonates mainly deposited in very shallow depressions on the floodplain as well as slight-brackish water in shore-shallow lacustrine environment.When the carbonate deposited,the climate was relatively dry and hot,the lake hydrology tended to close,volcanic activities were frequent and the lacustrine water supply was less than evaporation.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2011年第4期459-466,共8页
Acta Geologica Sinica
基金
教育部高等学校博士学科点专项科研基金(编号20060145016)
辽宁省国土资源厅计划项目(编号KJ222004102)资助的成果
关键词
辽西地区
义县组
碳酸盐岩夹层
沉积环境
western Liaoning
Yixian Formation
carbonate interlayers
sedimentary environment
