A New Interpretation on the Chengde Thrust

【作者】 汪洋；

【Author】 Yang Wang Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China

【机构】 Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China； School of Earth Science and Resources,China University of Geosciences,Beijing 100083,China；

【摘要】 <正>Since the first interpretation of tectonics around the area extending from Chengde City to Xiabancheng Town (Chengde County) as a north-verged folded thrust by Davis et al (1998, Geology, v.26, p43, and 2001 paper in GSA Memoir v.194, p171), the general attitude upon this interpretation is very negative among many domestic geologists. It may arise mainly due to their prejudice, misunderstanding and faulty observation. For example, the deny of He and Niu (2004, Geological Review, v.50, p464) on the long distance (> 40 km) displacement along Chengde thrust fault is mainly based on: ((?)) the similarity of lithofacies distribution, sequences and thickness of Proterozoic Changcheng strata involved in hanging and foot walls of Chengde thrust; and ((?)) the difference between the Changcheng strata of Chengde thrust plate and of its hypothetical root belt in Kuancheng area, 40 km or more southward far away. Unfortunately, they misunderstood the geometry of Davis’ Chengde thrust; hence He and Niu drew an E-W striking ’Jiyuqing fault’ in north of Xiabancheng Town as the southern trace of Chengde thrust (see their Fig.1). In fact, the southern trace of Chengde thrust turns southwest around Jiyuqing village, and is cut by Chengde County thrust fault in the area west of Xiabancheng Town. Therefore, the hanging wall Changcheng strata in southwestern portion of thrust plate were wrongly regarded as footwall strata by He and Niu. Meanwhile, they cannot identify the extensive recumbent folding and thrusting within Proterozoic strata in Kuancheng area as well as in vast southern part of Yanshan belt (cf. Wang et al, 2005, Beijing Geology, v. 17, no.2, p1). Accordingly, their second argument upon regional correlation of Proterozoic lithofacies and thickness relies on false appearance than fact.更多还原