Reconnaissance geology of the Wadi Shuqub Quadrangle, sheet 20/41 A, Kingdom of Saudi Arabia

Abstract

The Wadi Shuqub quadrangle (sheet 20/41 A) lies in the high mountainous part of the Hijaz plateau in west-central Saudi Arabia The quadrangle is underlain chiefly by Precambrian layered metasedimentary and metavolcanic rocks that are intruded by plutons ranging in composition from gabbroic to granitic, X The metasedimentary rocks include quartzite, phyllitic quartzite, phyllite, slate, argillite, granulite, schist, and marble. The metavolcanic rocks are mostly greenstone and greenstone tuff but include meta-andesite and metadacite. The rocks are in the greenschist and greenschist-amphibolite transition facies. The major plutonic rocks are tonalite and quartz diorite, which form a large batholith in the western part of the quadrangle. Smaller bodies of diorite and gabbro, granite, and complexes of mixed rocks are also present. Basalt of Quaternary age covers the Precambrian rocks near the eastern margin of the quadrangle, and alluvium underlies major wadis and flats. The main part of the Wadi Bidah mining district, including at least four ancient mining sites, is in the southeast part of the quadrangle. The district has produced gold from goldquartz veins, and has some potential for producing gold, silver, copper, zinc, and lead from massive sulfide deposits.

Geochemistry and preliminary assessment of resource potential for postorogenic granites of the southwestern Arabian Shield, Kingdom of Saudi Arabia

“…Several of the syenitic plutons vary from mafic to silicic in composition: Al Ajarda (Stoeser, 1985), Hawil (Green and Gonzalez, 1980), Jizarah (Greenwood, 1979), and Jabal Qunnah (samples 642 through 644, table 1). Samples collected during the current study show that only Jabal An is peralkaline as well as silica undersaturated, but Stoeser (1985) reports that the rim phase of Al Ajarda is aegirine-bearing which would indicate a peralkaline composition.…”

Reconnaissance investigations of ancient gold mines in the southern part of the Wadi Bidah District, Jabal Ibrahim and Al Aqiq quadrangles, Kingdom of Saudi Arabia

“…The dominantly metasedimentary unit continues to the north through the massive sulfide lens-bearing zones at Rabathan into the Wadi Shuqub quadrangle (Green and Gonzalez, 1980). Ferruginous chert diminishes to the north, and the calcareous rocks and carbonaceous material are not exposed near the northern boundaries of the two quadrangles.…”

Geological and geochemical studies in the Wadi Bidah District, Kingdom of Saudi Arabia

“…Quartz-feldspar porphyritic rocks and granodioritic intrusive rocks are probably related to a center of activity, but little is known of this relationship except that horn-blende granodiorite tends to be associated with the axis of the main western anticlinorium (Greenwood, 1975;Greene and Gonzalez, 1980). The intrusive rocks are probably somehow related to the major granitic center to the north.…”

“…The Wadi Shuqub quadrangle, which includes the northern part of the Wadi Bidah district, was mapped by Greene and Gonzalez (1980), who did not assign the layered rocks to any group and stratigraphic order of the units, however, stated "the true is uncertain." Table 1 (following) is taken in entirety from the report of the Riofinex Geological Mission (1979) and succinctly presents the stratigraphic succession according to five independent studies.…”

“…H. Allcott (1970), USGS, drilled three holes at the Ma'dan (Mahawiyah) ancient mine. L. Gonzalez, USGS, mapped part of the Wadi Shuqub quadrangle (sheet 20/41 A) at 1:100,000 scale; this quadrangle includes the northern two-thirds of the Wadi Bidah district (Greene and Gonzalez, 1980). A. R. Abo-Rashid (1971), DGMR, mapped the geology of an area east of the village of Al Mahawiyah that includes the Mahawiyah ancient mine.…”