摘要
通过对川西盆地下白垩统古流向的研究发现,川西盆地东缘早白垩世早期沉积的平均古流向为142°～145°,中、晚期沉积的平均古流向则为264°～288°,说明古流向发生了逆变。下白垩统泥质岩稀土、微量元素丰度的纵向变化表明,与此古流向逆变过程相对应沉积层段的元素丰度,也产生了明显的相对异常。这一地球化学异常既为该古流向逆变的存在提供了进一步的佐证,也揭示了该现象具有很好的、区域性的沉积地球化学响应。
The studies on the palaeocurrent of the Lower Cretaceous in the western Sichuan Basin reveal that in the eastern margin area of the basin,the vector mean of palaeocurrent direction in sediments of the early Early Cretaceous is from 142° to 145°,and in the middle-and-late Early Cretaceous sediments is from 264° to 288°.The results indicate that an inversion of palaeocurrent direction happened during this period.At the same time,the vertical abundance variation of trace elements and rare earth elements of the Lower Cretaceous argillaceous rocks in this basin shows that some elements have obviously relative abundance anomaly in corresponding sediments of this inversion.Such a geochemical anomaly not only provides further evidence for the existence of this inversion, but also reveals that it has a strong and regional sedimentary geochemical response.
出处
《古地理学报》
CAS
CSCD
北大核心
2010年第1期116-126,共11页
Journal of Palaeogeography：Chinese Edition
基金
地质过程与矿产资源国家重点实验室课题(编号:GPMR2008K01A)
中国石油化工股份有限公司重点项目(编号:G080006ZS286)联合资助
关键词
川西盆地
下白垩统
古流向逆变
泥质岩
稀土元素
微量元素
丰度异常
western Sichuan Basin Lower Cretaceous inversion of palaeocurrent mudstone rare earth element trace element abundance anomaly
