干旱区生态环境知识资源中心

The structural and geomorphological analysis of the area south of Umm Gheig contributed in unraveling and understanding the neotectonic evolution of the Central Eastern Desert of Egypt. The analysis of the landsat images, scale 1: 100,000 helped in identification and description of four major tectonic trends comprising N-S, E-W, NW-SE and NE-SW Twenty-six subhomogeneous drainage domains were defined reflecting complexity of their origin. Fault lines and general dip of sedimentary rocks are the main controllers of the drainage course. The structural factor has predominance in drainage development over the other controllers. Drainage anomaly of neotectonic origin comprising drainage meander, local braiding, deflected drainage lines, centripetal and centrifugal drainage and ridges were identified and mapped. A slip rate of 0.6 to 2.7 mm/y was estimated as a tentative and rough value along active faults in the study area. Active faults have priority over inactive faults. The NW-SE faults control the majority of the mountain fronts. Commonly, slope angles range from 5 to 15. The slopes are generally controlled by fault trends and there is a longitudinal offset of ridges due strike-slip faults. Weathering-limited and transportlimited slopes were recognized. Recorded anomalous widening and necking of valleys allowed to infer the sense of movement along the faults guiding the valley courses. Widenings and necks are sites of voids and restraining steps respectively that may refer to neotectonic activity along the guiding faults. Faults in different trends show complicated history. Linear valleys, shutter ridges, fresh scarps and fresh striations were recorded as neotectonic criteria.