Timing and composition of continental volcanism at Harrat Hutaymah, western Saudi Arabia

Journal of Volcanology and Geothermal Research
By: , and 

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Abstract

Harrat Hutaymah is an alkali basalt volcanic field in north-central Saudi Arabia, at the eastern margin of a large Neogene continental, intraplate magmatic province. Lava flow, tephra and spatter cone compositions in the field include alkali olivine basalts and basanites. These compositions contrast with the predominantly tholeiitic, fissure-fed basalts found along the eastern margin of the Red Sea. The Hutaymah lava flows were erupted through Proterozoic arc-associated plutonic and meta-sedimentary rocks of the Arabian shield, and commonly contain a range of sub-continental lithospheric xenoliths, although the lavas themselves show little indication of crustal contamination. Previous radiometric dating of this volcanic field (a single published K–Ar age; 1.8 Ma) is suspiciously old given the field measurement of normal magnetic polarity only (i.e. Brunhes interval, ≤ 780 Ka). We report new age determinations on 14 lava flows by the 40Ar–39Ar laser step heating method, all younger than ~ 850 Ka, to better constrain the time frame of volcanism, and major, trace and rare earth element compositions to describe the chemical variation of volcanic activity at Harrat Hutaymah. Crystal fractionation was dominated by olivine ± clinopyroxene at a range of upper mantle and crustal pressures. Rapid ascent and eruption of magma is indicated by the array of lower crustal and lithospheric xenoliths observed in lava flows and tephra. Modeling suggests 1–7% melting of an enriched asthenospheric mantle source occurred beneath Harrat Hutaymah under a relatively thick lithospheric cap (60–80 km).

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Timing and composition of continental volcanism at Harrat Hutaymah, western Saudi Arabia
Series title Journal of Volcanology and Geothermal Research
DOI 10.1016/j.jvolgeores.2016.01.010
Volume 313
Year Published 2016
Language English
Publisher Elsevier
Contributing office(s) Volcano Science Center
Description 14 p.
First page 1
Last page 14
Country Saudi Arabia
Other Geospatial Harrat Hutaymah
Online Only (Y/N) N
Additional Online Files (Y/N) N