"Harrat" is a plural form of a term given to the lava fields of the Arabian Penninsula. Harrat Ash-Shamah is located in NW Saudi Arabia and extends into Jordan and Syria. These fields are made of fluid basaltic lavas and have cinder cones, tuff rings, composite volcanoes and small shield volcanoes scattered across them. The basalts contain plagioclase, olivine and pyroxene minerals.
The volcanic activity which created the lava fields happened in five separate episodes. During the quiet periods between eruptions, winds blew sands onto the lavas, so that there is an inter-layering of sediments and lavas. The volcanic activity began 10-14 million years ago, and the most recent eruptions were only a few hundred years ago. Eruptions will probably resume in the future. The volcanic activity took place from long fissures, and the area has grabens, fault scarps and fractures.
Salf, S.I., "Field and petrographic characteristics of Cenozoic basaltic rocks, Northwestern Saudi Arabia.," Journal of African Earth Sciences, vol. 7, n. 5, pp. 805-809, 1988.
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