Paragenesia of Quaternary pediments and river terraces on the north piedmont of Wutai Mountains  

作　　者：ZHANG ShiMin REN JunJie NIE GaoZhong 

机构地区：[1]Institute of Geology, China Earthquake Administration, Beijing 100029, China [2]Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China

出　　处：《Chinese Science Bulletin》2007年第4期521-530,共10页

基　　金：Supported by the Joint Foundation of Seismology (Grant No. 101103);the project "Studies on Seismic Safety Evaluation and Anti-Seismic Structures" of China Earthquake Administration

摘　　要：A study has been made of the paragenetic relations of the pediments and river terraces on the northern piedmont of Wutai Mountains via geomorphologic mapping of 1:10000 scale, and an analysis on the role of tectonic, climatic, and drainage factors in the parageneses. The Quaternary pediments and river terraces on the north piedmont of Wutai Mountains united to constitute six steps of geomorphic surfaces. The episodic uplifting of fault blocks was the dominant factor in the formation of the unified surfaces, however climatic change and drainage diversities led to undulation of the surfaces. The second terrace of Yangyan River (T2) was formed in the last glacial maximum, when the river was in aggradational state. The third to fifth terraces were formed in interglacial stages, when the river was in equilibrium or degradational state. It is inferred that climate had no insignificant effect on the river incision caused by tectonic uplifting. In light of terraces dating, since the Quaternary the Wutai fault-block mountains experienced six rapid uplifting events, and the starting time of the last four events was respectively 1.2, 0.6, 0.13, and 0.02 Ma B.P.A study has been made of the paragenetic relations of the pediments and river terraces on the northern piedmont of Wutai Mountains via geomorphologic mapping of 1：10000 scale, and an analysis on the role of tectonic, climatic, and drainage factors in the parageneses. The Quaternary pediments and river terraces on the north piedmont of Wutai Mountains united to constitute six steps of geomorphic surfaces. The episodic uplifting of fault blocks was the dominant factor in the formation of the unified surfaces, however climatic change and drainage diversities led to undulation of the surfaces. The second terrace of Yangyan River （T2） was formed in the last glacial maximum, when the river was in aggradational state. The third to fifth terraces were formed in interglacial stages, when the river was in equilibrium or degradational state. It is inferred that climate had no insignificant effect on the river incision caused by tectonic uplifting. In light of terraces dating, since the Quaternary the Wutai fault-block mountains experienced six rapid uplifting events, and the starting time of the last four events was respectively 1.2, 0.6, 0.13, and 0.02 Ma B.P.

关 键 词：五台山北麓 构造隆起 断层悬崖 第四纪侵蚀面 河成阶地 共生作用 

分 类 号：P548.2[天文地球—构造地质学] P546[天文地球—地质学]