Moho depth and sediment thickness estimation beneath the Red Sea derived from satellite and terrestrial gravity data

作者:Salem Ahmed*; Green Chris; Campbell Simon; Fairhead J Derek; Cascone Lorenzo; Moorhead Lee
来源:Geophysics, 2013, 78(5): G89-G101.
DOI:10.1190/GEO2012-0150.1

摘要

We sought to map the depth and density contrast of the Mohorovicic discontinuity (Moho) across the Red Sea area and to model sedimentary thickness from gravity data. The gravity data that are used are a combination of satellite and terrestrial gravity data processed into a Bouguer anomaly grid. A 200-km low-pass filter was used to separate this grid into regional and residual gravity grids. We inverted the regional gravity grid to a Moho depth map based on a density contrast map that is constrained by published seismic results. The interpreted Moho is shallowest (%26lt;10 km) along the axis of the central Red Sea, similar to 13 km along the axis to the south, and similar to 20 km in the northern Red Sea. The depth increased to similar to 20-25 km at the coast and 35-40 km in the adjacent continents. The residual gravity data provided insights into the tectonic fabric along the whole rift and provided a good correlation with magnetic lineaments where these are available. We used the complete Bouguer anomaly to model sedimentary thicknesses constrained by wells and the interpreted Moho. The modeling results are consistent with the presence of large-scale, ridge parallel tilted fault blocks forming subbasins with a maximum depth of about 6-7 km. Our models suggest that the northern Red Sea has an asymmetric basement surface with the western side deeper than the eastern side. The results indicate the presence of oceanic crust in the central and southern parts of the Red Sea, but not in the north. The very thin crust and interpreted oceanic crustal density in the central Red Sea suggest that this area is fully oceanic - although possibly quite young.

  • 出版日期2013-10