Author: MONEY Yanpeng Yang Wentao Ql Shuaishuai | Time: 2020-07-10 | Counts: |
doi:10.16186/j.cnki.1673-9787.2020.4.4
Received:2019/05/08
Revised:2019/06/06
Published:2020/07/15
Geochemical characteristics response of mudstone in the southern margin of the North China Craton during the Paleozoic-Mesozoic structural transition
WANG Yanpeng, YANG Wentao, QI Shuaishuai
Institute of Resource and Environment, Henan Polytechnic University,Jiaozuo 454000,Henan, China
Abstract:The successive sedimentary record of the late Paleozoic-early Mesozoic in Yiyang area, western Henan, provides an important window for studying the sedimentary and tectonic evolution of the southern margin of the North China Craton. Based on the analysis of geochemical characteristics of the main quantity, trace elements and rare earth elements of the mudstone from the Middle Permian to the Lower Triassic in the source area, this paper discussed its attribute characteristics, including the source rock composition, the chemical weathering conditions and the structural background of the source area, and defined the source area of the sediment. The results showed that the source rocks of Middle Permian-Lower Triassic mudstones in Yiyang area were mainly felsic in the upper crust, and which were mainly granitoids with the participation of ancient sedimentary rocks;The source rocks of the Shihezi formation had experienced strong weathering and the sediments might have undergone sedimentary recycling under stable tectonic environment, however, the chemical weathering decreased from the stage of the Sunjiagou Formation, the sediments began to transform to the primary sediments in the tectonic active area ; The structural background of the source area had a trend of evolution from the passive continental margin of the Shihezi Formation to the mixed background of the passive continental margin, continental island arc and active continental margin of the Sunjiagou formation, and finally to the continental island arc and active continental margin of the Liujiagou formation and the Heshanggou formation in the vertical direction. Combined with the evidence of paleocurrent and detrital zircons, it was suggested that the southern margin of North China and the northern Qinling might have a strong uplift from Pingdingshan sandstone section of Sunjiagou formation and become the main provenance of Yiyang area. These significant geochemical differences provided an important geochemical basis for the Paleo-mesozoic tectonic transformation in the southern margin of the North China Craton.
Key words:southern margin of the North China Craton;Yiyang area;Middle Permian -Lower Triassic;mudstone;geochemical characteristic;provenance analysis;tectonic transition