ASPRS 2009 Annual Conference Baltimore, Maryland  March 9-13, 2009 IMAGE PROCESSING AND ANALYSIS USING LANDSAT ETM + IMAGERY FOR LITHOLOGICAL MAPPING AT FAWAKHIR, CENTRAL EASTERN DESERT OF EGYPT Reda Amer, PhD Student Timothy Kusky, Paul C. Reinert, Professor and Chair of Natural Sciences Abduwasit Ghulam, Research Professor Department of Earth and Atmospheric Sciences and Center for Environmental Sciences Saint Louis University St. Louis, MO 63103 USA ramer@slu.edu tkusky@gmail.com awulamu@slu.edu ABSTRACT A data fusion technique is presented for lithological mapping in arid environments. Landsat Enhanced Thematic Mapper (ETM + ) visible (VIS), near-infrared (NIR) and infrared (IR) bands have been enhanced using image fusion with a high spatial resolution panchromatic band of the same data set. The Hue, Saturation, and Value (HSV) transform is used to convert RGB coordinates into the color coordinates (HSV). Later, Principal Component Analysis (PCA) is applied on the fused (HSV) image for mapping ophiolitic and granitic rocks at Fawakhir in the Central Eastern Desert of Egypt. A revised lithologic map of the Fawakhir area is proposed based on the interpretation of Landsat ETM image results and field verification work. It is concluded that the proposed methods have great potential for lithological mapping in arid and semi arid regions. INTRODUCTION Most of the Precambrian outcrops in Egypt are restricted to the area between the Nile and the Red Sea and the adjacent southern Sinai Peninsula. The Fawakhir area is located 93 km west of the Red Sea coast, along the Qift- Quseir highway in the Central Eastern Desert of Egypt at Lat. 26˚ 00′ 17″ N, and Long. 33˚ 35′ 42″ E (Fig. 1). The Eastern Desert of Egypt is a part of the Pan-African Arabian-Nubian Shield, occupied by igneous and metamorphic rocks that were formed during the evolution of the Mozambique Ocean and its closure culminating in the East African Orogeny marking the collision between East and West Gondwana and the closure of the Mozambique Ocean 600 Ma ago (Stern, 1994; Kusky et al., 2003). The Central Eastern Desert is almost exclusively built up of island arc magmatic rocks, ophiolitic mélange and associated rocks, together with subordinate molasse-type sediments and late-tectonic volcanics and granitoid intrusives (El Ramly et al., 1993). The Fawakhir area is occupied mainly by ophiolitic mélange represented by serpentinites, metagabbro, and metabasalt, then intruded by granitic rocks, and overlain by Hammamat sediments. The Fawakhir granite pluton hosts El Sid and El Fawakhir Gold Mines, which are two of several gold mines in the Eastern Desert of Egypt that have been extensively worked since Pharaonic and Roman times (Amer et al., 2008). Remote sensing techniques have been used successfully in lithological mapping for the Arabian Nubian shield and for other areas worldwide by several authors (e.g. Abrams et al., 1983 & 1988; Sultan et al., 1986; Sabins, 1997; Abdelsalam and Stern, 1999; Rowan et al., 2003 Gad and Kusky 2006). Sultan et al., (1986) used Landsat TM RGB band ratios (5/7, 5/1, 5/4 * 3/4) for mapping serpentinites in the Eastern Desert of Egypt. Landsat ETM band ratio images (5/3, 5/1, 7/5) in RGB and (7/5, 5/4, 3/1) in RGB Gad and Kusky, (2006) are used for mapping serpentinites in the Barramiya area in the Central Eastern Desert of Egypt. Amer et al., (2008) proposed new ASTER band ratios ((2+4)/3, (5+7)/6, (7+9)/8) in RGB by analysis of the image spectra of the ophiolitic rocks at Fawakhir, Central Eastern Desert of Egypt. They also used the Principal Component Analysis (5, 4, 2) in RGB of ASTER image to present a revised lithologic map of the Fawakhir area.