Characteristics of Weathering Crust and Formation of Planation Surface in Wangmangling at the Southern Edge of Taihang Mountain
ZHANG Lei;ZHANG Xu-jiao;WU Fa-dong;DENG Hui-juan;CHEN Kang;Cores and Samples Center of Land and Resources,China Geological Servey;School of Earth sciences and Resources, China University of Geosciences(Beijing);
Through field investigation, indoor test analysis and regional comparison, the characteristics of the weathering crust in the Wangmangling area and the formation environment of the plane of the surface are discussed. From the aspects of geomorphology, palaeokarst, and weathering crust, it is verified that there are planation surface(1 400~1 600 m) and paleo-valley-mountain surface(800~1 100 m) in Wangmangling. Through the geochemical test of the weathering crust, it is believed that the planation surface was formed in a hot and humid climatic environment, and the aluminiferization effect of the weathering crust on the weathering crust was obvious, but it was still moderately developed; paleo-valley-mountain surface was formed in a warm and humid climatic environment, and its weathering crust was not strong enough for desilication, and its development was moderately weak. Finally, through regional comprehensive comparisons, it is concluded that the planation surface is Taihang planation surface which was formed in Oligocene, and the paleo-valley-mountain surface is Tangxian planation surface which was formed in Pliocene.