Reconnaissance geology of the Al Ba'ayith quadrangle, sheet 26/41 D, Kingdom of Saudi Arabia

Open-File Report 85-617

, , and



The Al Ba'ayith quadrangle, located in the northeastern part of the Arabian Shield, is underlain by upper Proterozoic intrusive rocks and volcanogenic layered sequences bounded by unconformities. The oldest rocks are silicic volcanic rocks of the Banana formation that is tentatively assigned to the Hulayfah group. Successively younger layered rocks are the Maraghan formation of the Murdama group, consisting of lithic graywacke, siltstone, and shale; the Hibshi formation, coarse-grained lithic sandstone and conglomerate; the Sufran formation, dacitic and andesitic lava flows and ash-flow tuffs; the Jurdhawiyah formation, andesitic flows and agglomerate, and conglomeratic sandstone; and the Hadn formation, rhyolite flows and ash-flow tuffs, conglomerate, sandstone, and andesite flows.

Plutonic rocks are of four main age groups: an early group consisting of orthogneiss of granodioritic and granitic composition, and metagabbro; a pre-Hibshi group consisting of the Murran complex (diorite and quartz diorite) and quartz monzodiorite; a post-Hibshi group, consisting of altered mafic plutonic rocks, granodiorite of the Idah suite, and monzogranite of the Shuwayman suite; and a latest Precambrian group of highly evolved granitic rocks, consisting of alkali-feldspar granite, granophyre, and syenogranite.

Structures in the orthogneiss and metagabbro trend northeast to northwest, and in the Murran complex, generally east. The Maraghan formation was folded and thrust over the Hibshi formation along the northeast-trending Raha fault. The Jurdhawiyah formation is at the northern margin of the east-trending Shuqrah basin. Northwest-trending left-lateral faults probably belong to the Najd fault system.

Quaternary surficial deposits mantle large areas of the quadrangle, and consist of sheet gravel, alluvial fan gravel, eolian and alluvial sand and silt, and sabkhah deposits.

Gold-bearing quartz veins occur associated with small plutons of the Idah suite in the southeastern part of the quadrangle, and have been mined in the past. Ironstones, near Murran in the center of the quadrangle contain trace amounts of silver and gold.

Study Area

Additional publication details

Publication type:
Publication Subtype:
USGS Numbered Series
Reconnaissance geology of the Al Ba'ayith quadrangle, sheet 26/41 D, Kingdom of Saudi Arabia
Series title:
Open-File Report
Series number:
Year Published:
U.S. Geological Survey
Publisher location:
Reston, VA
ii, 38 p. :ill., maps ;28 cm.
Saudi Arabia
Online Only (Y/N):
Additional Online Files (Y/N):