Late Neoarchean Continental Crust Magmatism and Jurassic Hydrothermal Activity in the Duozhuang Area of Western Shandong, China: Evidence from Zircon in Monzogranite
摘要
The composition, formation time, material sources and evolution processes of craton basements have been research hot spots in the field of earth science. Detailed research on these issues is conducive to the understanding of the early evolution processes of the earth. The basement of North China Craton (NCC), which was formed by the amalgamation of several small continental blocks, has a very large outcrop area and has attracted much attention. The region of Western Shandong, which is a typical region for the exposure of the Precambrian basement of NCC, is an ideal research base for the Precambrian history of NCC. In this paper, a monzogranite sample from the Duozhuang area of this region has been collected for LA-ICP-MS zircon U–Pb dating and trace element analysis. According to the experiment, the age of the sample is about 2508 Ma and it is a product of late Neoarchean continental crust magmatism. The sample is orogenic and its formation may have been related to continent-continent or ocean-continent collision. Thus, cratonization may have occurred as early as late Neoarchean in some regions of NCC. Besides, the lower intersection between the discordant line of the sample and the concordia curve is 172.4 Ma, which indicates that a lead loss event caused by hydrothermal activity took place in zircon of this sample at about 172.4 Ma. As a result, it can be inferred that a major craton destruction event may have occurred in this region at about 172.4 Ma.