Abstract
This study presents the first comprehensive surface heat production data from the Arabian Shield, based on radiometric analysis of some 1200 rock samples, collected from the major ultramafic to felsic units along two transects crossing the different structural provinces, in the central and northern parts of the Shield. For the convenience of the presentation of the data, the two transects are divided into five terranes. Comparison of heat production averages and ranges of lithologically equivalent units in the different terranes shows considerable variation, depending on the geotectonic setting. Granitoids are the main contributor of heat production, variation in their abundance and composition are main factors in heat generation estimates. The largest contrast in heat production exists between rock units of both the Miskah and Madinah terranes, particularly the granitoids due, most probably, to difference in their general geotectonic evolution. The Miskah granitoids were evolved within a microplate underlain by Middle Proterozic granitoid basement, whereas the Madinah granitoids are interpreted to have been formed within the cores of Late Proterozoic ensimatic island arc terrane. Granitoids from the other terranes show no significant differences in heat production averages. The overall weighted HPU average for the northern Arabian Shield is estimated as 4.7 which corresponds to a heat flow of 1.13 HFU. One of the most important findings of this study is the delineation of a northwest trending high heat production province associated with mineralization along both the Nabitah suture zone and the Najd fault system.
Published Version
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