Evolution of the Asir terrane and Phanerozoic rifting in southwestern Saudi Arabia
The Asir terrane, defined by D.B. Stoeser and V.E. Camp, in southwestern Saudi Arabia was formed from about 1200 Ma to 560 Ma by the coalescence of the Baish ensimatic island-arch complex and the Andean-type Tarib arc complex. In this period, the Afif and Ar Rayn exotic terranes impinged from the east and were accreted to the Asir terrane along a west-directed subduction zone to form the Nabitah suture. Mapping on the eastern side of the Asir terrane by the author shows that the Ablah sedimentary basin was compressed and tectonically incorporated into west-directed thrust faults as the Asir terrane was accreted to the African craton. A saprolite mantle formed over the Asir terrane during a late-Precambrian-early Paleozoic episode of chemical weathering. Later, the terrane gradually subsided and was covered by Paleozoic seas in which the Wajid Sandstone and the Kholan and Amran Limestones were deposited. Initiation of a thermal cell at the Afar triple junction during the latest Cretaceous or early Tertiary caused crustal attenuation and sagging into a proto-Red Sea rift. Rifting and uplift of the Arabian Shield by as much as 2000 meters since the middle Miocene are indicated by deposition of the Asir group volcaniclastic and clastic rocks, emplacement of shallow, layered-intrusive rocks and basaltic dikes, and displacement of the Wajid Sandstone. Proterozoic thrust faults were reactivated as normal and strike-slip faults by Miocene rifting, and sandstone dikes were injected downward into the faults. Quaternary volcanism, stream incision, and historic earthquake activity are evidence of continued uplift.
- Research Organization:
- Geological Survey, Denver, CO (USA)
- OSTI ID:
- 6612347
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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