Effect of Precambrian basement structure on heat flow distribution in Eastern Arabia

Abstract

A new model of the thermal structure of the easternmost portion of the Arabian continental crust is presented. Detailed heat flow models based on more than 660 temperature measurements from 230 exploration wells have been performed over an area of 166,000 km² in size, spanning from the Arabian Gulf to the Eastern Arabian Shield. Geothermal gradients exhibit an increase from 22 ºC/km on the Arabian Platform, to 35 ºC/km in the Faydah-Jafurah Basin. Related surface heat flow (SHF) increases in the same direction from 44 to 72 mW/m². Heat flow analysis reveals that the radiogenic heat contribution to the total surface heat flux accounts for up to 58%, and the Moho heat flux for 42%, accordingly. From thermal modeling constraints, i.e., matching borehole temperature data and resulting heat flow distribution, it can be inferred that the crust underneath the easternmost Arabian Platform (east of En Nala terrane suture) is significantly more felsic (~ 2.5 µW/m³) than the central Arabian Platform and Arabian Shield (~ 0.9 µW/m³). This is supported by deep wells intersecting rocks of granitoid composition east of the Arabian Shield. Reconstructions of lithosphere geotherms has revealed Moho temperatures around 850–900 °C. Moho heat flow is in the order of 26 mW/m². Thermal modeling revealed a spatial relationship between regional surface heat flow distribution, crustal structure and the extension and composition of basement terranes. The study demonstrates that the Proterozoic crustal configuration has an impact on the Phanerozoic thermal evolution and its subsidence pattern.

Graphical abstract

Modeled temperature (C) at the top of the basement.