EVALUATION OF THE MINERAL POTENTIAL OF THE SAUDI ARABIAN SHIELD: A GIS APPROACH

The Precambrian Shield of Saudi Arabia covers more than 680,000 km² of the western Arabian Peninsula, encompassing a third of Saudi Arabia. Rocks there are principally upper Proterozoic volcanics and volcanoclastics intruded by igneous plutons and dykes. More that 2,100 metallic mineral occurrences are known throughout the Shield, 138 of which have been shown to contain significant resources. This research extends the potential of known occurrences, and predicts where similar deposits may lie concealed.

Data layers covering the Shield include topography, geology, lineaments, lithotectonic terranes, gravity, magnetics, and rock ages. Geographic boundaries, and roads and cities provide additional coverages. Occurrences of 12 metals were utilized as "skeletons" upon which to examine spatial relationships between mineral locations and the data in the GIS layers. These relationships in turn were used to produce four exploration models: (1) Fuzzy Logic Model with Gamma Operation (FLM-GO), (2) Boolean Logic Model (BLM), (3) Index Overlay Model with Binary Evidence Maps (IOM-BEM), and (4) Index Overlay Model with Multi-Class Maps (IOM-MCM).

The FLM-GO identified 838 km² of high silver potential in the AdDawadimi sub-terrane of the Afif terrane, and 14,146 km² of high copper potential mainly in the Zalm sub-terrane of the Afif terrane. The Boolean Logic Model highlighted 14 km² of silver potential in the AdDawadimi, and 4,153 km² of copper potential in the Zalm. The IOM-BEM highlighted 44 km² and 8,397 km² respectively for silver and copper in the sub-terranes, and the IOM-MCM identified 412 km² and 9,633 km² in the two sub-terranes. All of the models highlight known occurrences of silver and copper, plus significant areas where there are no known deposits - the latter are particularly intriguing, especially those identified by IOM-MCM modeling. Results vary but are equally intriguing for gold and the other metals in the data base.