APPLICATION OF REMOTELY SENSING DATA IN THE GEOLOGIC AND RADIOACTIVE MAPPING OF WADI FATIRAH PRECAMBRIAN ROCKS, NORTH EASTERN DESERT, EGYPT

Document Type : Original Article

Authors

1 Dept. Geol., Fac. Sciences, Cairo Univ

2 Nuclear Materials Authority, Cairo, Egypt

Abstract

The present study aims to integrate spectral analysis results of multispectral Landsat-8 and ASTER data
besides airborne gamma-ray spectrometric data in geologic and radiometric mapping as well as alteration
types of Wadi Fatirah area, North Eastern Desert, Egypt. The applied image processing techniques
comprising Color Band Composites, Principal Component Analysis, Crosta technique and Band Ratio were
efficient in lithological units discrimination and alteration types identification. The airborne gamma-ray
spectrometric maps discriminate the younger granites in the study area but it could not differentiate between
their phases. The remote sensing products are verified by detailed field, petrographic and radiometric
analysis. The results are elaborated as a precise geological map of 1:50,000 scale with metavolcanics
(oldest), older granitoids, Dokhan volcanics, younger gabbros, younger granites and post granitic dikes and
pegmatites (youngest) rock units, and tracing the hydrothermal alterations in form of propylitic, phyllic
and gossan as well as illite, kaolinite, limonite, hematite, ferromagnesian and hydroxyl distribution maps.
Additionally, the radioactive anomalies are mainly related to the younger granites and pegmatite bodies
that mainly associated with ferrugination (iron oxides and hydroxides alteration). The most promising
radioactivity are delineated as pegmatite bodies at Wadi Abu Zawal and Wadi Abu Shihat.