Integration of remote sensing technique and field data in geologic mapping of an ophiolitic suture zone in western Arabian Shield

Abstract

© 2017 Elsevier Ltd. Ophiolitic suture zones are characterized by highly deformed rocks of different types and metamorphism in small area. These characteristic conditions make each rock unit is hardly followed on the field and mapped on a small scale. Thus, the present study is suggested to map the rocks and structures of Tharwah part of the Tharwah-Bi'r Umq suture zone in western Arabian Shield using remote sensing techniques and field verification.Rock type, thickness, geometry, isotropism, metamorphism and weathering control mainly the reflectance behavior of the rocks. Thus, the remote sensing works include the spectral signature curves analysis of the present rock units; some relational behavior which led to eight characterized band ratios for distinguished the rock units; moreover four false color band ratios composite were determined to create lithological map of the investigated area which were [7/5, 6/3, 6/7], [6/7, 6/2, (6/5)*(4/5)], [6/2, 7/3, 3] and [6/7, 6/5, 4/2]. Convolution filtering process and resulted lithologic map were used as two components for developing the geologic structure mapping.Although the diversity of rock types and intense structural deformation, the rock units and their affecting structural deformation are mapped clearly on the images and show a significant précised map after field verification, on compared with the other published maps. Tectonically, the thrust sheets affecting the ophiolite sequence were developed initially by a northwestward contractional tectonic event that was followed by an east-west contractional event which induced a transpression movement on the pre-existing thrust and foliation planes.