【摘 要】
：
Metavolcanic and metasedimentary rocks from the Paleozoic tectono-stratigraphic units along the northern margin in the Dabie orogen show that there are two type
【机 构】
：
Faculty of Earth Resources,Institute of Geochemistry
论文部分内容阅读
Metavolcanic and metasedimentary rocks from the Paleozoic tectono-stratigraphic units along the northern margin in the Dabie orogen show that there are two types of Pb isotopic compositions, which have some affined regularity with tectonic subdivision. Compared with the main tectonic units of the Qinling orogen, the Dingyuan Formation should be the part of the South Qinling orogenic belt or the northern margin of the Yangtze craton, characterized by less radiogenic Pb isotopic composition, and the Guishan Formation, Nanwan Formation-Foziling Group and the Carboniferous should be the part of the North Qinling orogenic belt which is extended to the east, characterized by more radiogenic Pb isotopic composition. These facts combined with the distribution of the geological units suggest that the Paleozoic subduction zone between the Yangtze and North China cratons should be located in the north boundary of the Nanwan Formation-Foziling Group or somewhere that is covered by the Nanwan Formation-Foziling Group now. From the Pb isotopic evidence and suggestion presented here, one aspect of the constraint is provided for determining the position of the Triassic collision suture between the two cratons.
其他文献
The transport from atmosphere is a more important pathway than that from rivers for certain elements and compounds in the remote ocean. The desert and those ari
了解和掌握隧道止水带作业工艺流程、操作要点和相应的工艺标准,有效的减少和杜绝隧道结构渗漏水的发生,对指导、规范隧道防排水施工,提高工程质量起着关键作用.
随着科技进步,电子文件与电子档案越来越广泛的应用于日常办公与管理.电子档案具有优于纸质档案的很多特征,但也同时伴有自身的缺陷.在对这些进行分析的基础上,提出了如何克
扎实推进企业反腐倡廉建设需要培育和实践廉洁从业的理念,完善制度的刚性约束和控制,维护制度的刚性作用,整合预警监督资源.
Three carbonate ocelli-bearing lamprophyre dykes have been found in the Laowangzhai and Beiya gold orefields in the northern sector of the Ailaoshan gold deposi
Reconstructions of past climate based on pollen data have formed a robust approach and produced a great of products in time scales from a millennium to ten mill
A 50-m firn core drilled in Princess Elizabeth Land, Antarctica, during the 1996/1997 Chinese First Antarctic Inland Expedition, has been measured for δ 18O an
On the basis of the study of volcanic products during 1199-1200AD eruption of Baitou Mountain (Baitoushan), the released volatile content was estimated by compa
The prediction of groundwater level is important for the use and management of groundwater resources. In this paper, the artificial neural networks (ANN) were u
如何确保路基工程施工质量,加快工程进庹,提高经济效益,一直是工程建设者们探讨的问题.文章对影响公路工程路基稳定性、平整度的相关因素及其处理方法进行分析探讨.