Analysis of Remote Sensing Data for Geologic Mapping -
Ultrahigh Pressure Metamorphic Belt and Collisional Tectonics of
The Dabieshan Orogenic Belt, Central Eastern China*
Zhang Wenhua, Zhao Zhongyan, Wang Changjiang
Laboratory of Lithosphere Tectonic Evolution, Institute of Geology,
Chinese Academy of Sciences, Beijing 100029, China
Tel: (86)-010-6202-7766 Fax : (86)-010-6237 5167
He Guojin, Ho Deyong
Chinese Satellite Ground Station, Chinese Academy of Sciences,
Beijing, 100086, China. Tel : (86)-010-6255-9679
Abstract
Processing methods were tested to effectively enhance the spectral and spatial information of the images. The image processing approach used in this study revealed previously unrecognized major structures and some lithologic units. Geological evidences showed the Dabieshan mountain is characterized by four linear tectonic belts trending NWW, which formed during tectonic collision between Sino-Korean and Yangtze plates in the Triassic Magnetotelluric survey revealed that a major decollement at 15-20 km depth runs 150 km directly underneath the Dabieshan. Above the decollement, the four tectonic belts formed a series thrust sheets and accommodated all the deformation. Below the decollement relatively intact Yangtze plate underthrust the Dabieshan over 200 km from the foreland fold and thrust belt of the Yangtze to the Northern Haiyang belt of the Sino-Korean plate.
Introduction
The study area is located at the Southwestern Anhai Province (Fig. 1). Dabieshan is one of the few orogenic belts in the world where diamond-and coesite-bearing ultrahigh pressure (UHP) metamorphic rocks are found in crustal environment (Wang et al., 1989; Okay et al., 1989; Xu et al., 1992). In the last a few years, studies in detail by geologists from many countries have given a good views (e. g. Okay et al., 1989; Wang, et. al., 1992; Li et al., 1989, 1993; Cong, 1996; Zhai, 1996).
Fig. 1. Location of the studied area in Dabieshan, Anhui Province Eastern China.
High ground resolution satellite imagery has been used to detect Dabeishan tectonic units. Therefore, when examining a Landsat TM image or aerial photographs of the Dabeishan, a number of northwest-southeast and northeast trending liner features can be observed.
In this paper we provide our present knowledge of the UHP metamorphic belt, regional geology and deep structures of the Dabieshan revealed by Magnetotelluric survey, Remote Sensing data and discuss the tectonic units and evolution of the Dabieshan organic belt.
