Relationship between Curie isotherm surface and Moho discontinuity in the Arabian shield, Saudi Arabia

Abstract

The Arabian shield is a Precambrian complex of igneous and metamorphic rocks located approximately one-third of the way across the western Arabian Peninsula, with uncommon exposures along the Red Sea coast. We used aeromagnetic data acquired by others over the past several decades to estimate the depth to the Curie temperature isotherm throughout this region. Our goal was to further understand the lithospheric structure, thermal activity, and seismicity to assist in geothermal exploration. We also compared the Curie temperature isotherm with the crustal thickness to investigate the possibility that mantle rocks are magnetic in some parts of the Arabian shield.Depths to the Curie isotherm were estimated by dividing the regional aeromagnetic grid into 26 overlapping windows. Each window was then used to estimate the shape of the power spectrum. The windows had dimensions of 250×250km to allow investigation of depths as deep as 50km. The results show the presence of a Curie isotherm at a depth of 10–20km near the Red Sea, increasing to 35–45km in the interior of the Arabian shield. The Curie isotherm generally lies above the Moho in this region but deepens into the mantle in some locations, notably beneath the Asir Terrane.