Geology and ore deposits of the Mahd Adh Dhahab District, Kingdom of Saudi Arabia

Open-File Report 76-865
By: , and 



Mahd adh Dhahab is the principal gold-silver mine in Saudi Arabia; it was productive during three principal periods, two during ancient times (about 950 B.C. and 750-1258 A.D.) and one in modern times (1939-54). The early production is not known, but the recorded production in 1939-54 is 765,768 fine ounces gold and 1,002,029 ounces silver.

The district is underlain by a sequence of pyroclastic and clastic rocks which probably belong to the Murdama Group. From oldest to youngest the units are andesite, lower agglomerate, lower tuff, upper agglomerate, and upper tuff. These units have been tilted northerly, forming a homocline, and they are complexly broken by six sets of faults; three of these sets, which strike N.25°-30°W., N.10°W. to N.20°E., and N.30°-60'E., contain productive quartz veins.

The principal ore minerals are pyrite, chalcopyrite, sphalerite, galena, and minor tetrahedrite, argentite, and native gold and silver. The gold and silver occurs finely disseminated in the veins and in the altered selvages of the veins. Widespread potassic and propylitic alteration accompanied the ore-forming processes. Potassium feldspar was introduced during an early stage of vein formation. Isotopic analyses of lead in vein potassium feldspar and galena yield a model age of about 900-1050 million years with the possibility of the original lead source having been remobilized about 600 million years ago. Chlorite and carbonate are also prominent vein minerals.

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Geology and ore deposits of the Mahd Adh Dhahab District, Kingdom of Saudi Arabia
Series title Open-File Report
Series number 76-865
DOI 10.3133/ofr76865
Year Published 1976
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description Report: ii, 28 p.; Map: 28 cm.
Country Saudi Arabia
Online Only (Y/N) N
Additional Online Files (Y/N) N