A three-dimensional Moho depth model beneath the Yemeni highlands and rifted volcanic margins of the Red Sea and Gulf of Aden, Southwest Arabia

Knowing Moho discontinuity undulation is fundamental to understanding mechanisms of lithosphere-asthenosphere interaction, extensional tectonism and crustal deformation in volcanic passive margins such as the study area, which is located in the southwestern corner of the Arabian Peninsula bounded by the Red Sea and the Gulf of Aden. In this work, a 3D Moho depth model of the study area is constructed for the first time by inverting gravity data from the Earth Gravitational Model (EGM2008) using the Parker-Oldenburg algorithm. This model indicates the shallow zone is situated at depths of 20 km to 24 km beneath coastal plains, whereas the deep zone is located below the plateau at depths of 30 km to 35 km and its deepest part coincides mainly with the Dhamar-Rada’a Quaternary volcanic field. The results also indicate two channels of hot magmatic materials joining both the Sana’a-Amran Quaternary volcanic field and the Late Miocene Jabal An Nar volcanic area with the Dhamar-Rada’a volcanic field. This conclusion is supported by the widespread geothermal activity (of mantle origin) distributed along these channels, isotopic data, and the upper mantle low velocity zones indicated by earlier studies.

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