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A crustal transect across the Oman Mountains on the eastern margin of Arabia

Ali I. Al-Lazki, Dogan Seber, Eric Sandvol and Muawia Barazangi
A crustal transect across the Oman Mountains on the eastern margin of Arabia
GeoArabia (Manama) (2002) 7 (1): 47-78

Abstract

The unique tectonic setting of the Oman Mountains and the Semail Ophiolite, together with ongoing hydrocarbon exploration, have focused geological research on the sedimentary and ophiolite stratigraphy of Oman. However, there have been few investigations of the crustal-scale structure of the eastern Arabian continental margin. In order to rectify this omission, we made a 255-km-long, southwesterly oriented crustal transect of the Oman Mountains from the Coastal Zone to the interior Foreland via the 3,000-m-high Jebel Akhdar. The model for the upper 8 km of the crust was constrained using 152 km of 2-D seismic reflection profiles, 15 exploratory wells, and 1:100,000- to 1:250,000-scale geological maps. Receiver-function analysis of teleseismic earthquake waveform data from three temporary digital seismic stations gave the first reliable estimates of depth-to-Moho. Bouguer gravity modeling provided further evidence of depths of the Moho and metamorphic basement. Four principal results were obtained from the transect. (1) An interpreted mountain root beneath Jebel Akhdar has a lateral extent of about 60 km along the transect. The depth-to-Moho of 41 to 44 km about 25 km southwest of Jebel Akhdar increased to 48 to 51 km on its northeastern side but decreased to 39 to 42 km beneath the coastal plain farther to the northeast. (2) The average depth to the metamorphic basement was inferred from Bouguer gravity modeling to be 9 km in the core of Jebel Akhdar and immediately to the southwest. A relatively shallow depth-to-basement of 7 to 8 km coincided with the Jebel Qusaybah anticline south of the Hamrat Ad Duru Range. (3) Based on surface, subsurface, and gravity modeling, the Nakhl Ophiolite block extends seaward for approximately 80 km from its most southerly outcrop. It has an average thickness of about 5 km, whereas ophiolite south of Jebel Akhdar is only 1 km thick. The underlying Hawasina Sediments are between 2 and 3 km thick in the Hamrat Ad Duru Zone, and 2 km thick in the Coastal Zone. (4) Southwest of Jebel Akhdar, reactivated NW-oriented strike-slip basement faults that deformed Miocene to Pliocene sediments were inferred from the interpretation of seismic reflection profiles.


ISSN: 1025-6059
Serial Title: GeoArabia (Manama)
Serial Volume: 7
Serial Issue: 1
Title: A crustal transect across the Oman Mountains on the eastern margin of Arabia
Affiliation: Cornell University, Ithaca, NY, United States
Pages: 47-78
Published: 2002
Text Language: English
Publisher: Gulf Petrolink in Bahrain, Manama, Bahrain
References: 51
Accession Number: 2004-074866
Categories: Economic geology, geology of energy sourcesApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., strat. cols., 1 table, geol. sketch maps
N22°00'00" - N24°00'00", E56°30'00" - E58°00'00"
Country of Publication: Bahrain
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200422
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