new constraints on Red Sea rifting from correlations of Arabian and Nubian Neoproterozoic outcrops

Abstract

New constraints on the mechanics of Red Sea opening were obtained by correlating Neoproterozoic outcrops of the Arabian and Nubian Shields along two thirds of the Red Sea coastlines. Using a mosaic of 23 Landsat thematic mapper scenes (5×10 5 km²) together with field, geochemical, and geochronological data, we identified and mapped lithologic units, mobile belts, and terranes within the Arabian and Nubian Shields. Features best align if Arabia is rotated by 6.7° around a pole at latitude 34.6°N, longitude 18.1°E. Implications of our reconstruction include (1) the amount of continental crust underlying the Red Sea is small because the restored Red Sea coasts are typically juxtaposed, (2) only a single pole is needed, implying that the Arabian and Nubian Shields were rigid plates during Red Sea rifting, (3) coastlines reorient to align with preexisting structures, suggesting the rift propagated in part along pre‐existing zones of weakness, (4) large sinistral displacements of up to 350 km along the Red Sea are not supported, (5) the pole is inconsistent with the Pliocene‐Pleistocene motion along the Dead Sea transform (pole: 32.8°N, 22.6°E +/− 0.5° [Joffe and Garfunkel, 1987]), indicating that more than one phase of motion is required to account for the Red Sea opening. However, our pole is similar to that for the total motion along the Dead Sea transform (pole: 32.7°N, 19.8°E +/− 2° [Joffe and Garfunkel, 1987]), suggesting that the motion between Arabia and Nubia was parallel to the total motion along the Dead Sea transform.