Construction of Surface Sediment Data Bases, Seafloor Sediment Studies in the Middle East.

Abstract

Abstract : We prepared the first systematic survey of seafloor sediment type in the Red Sea, Gulf of Aqaba, Gulf of Suez, and Gulf of Oman. We mapped bottom annotations on archived navigation charts, unpublished surveys, descriptions published in journals, and observations from NGDC. The maps show the affects of laterally varying rates of tectonic uplift, composition of sedimentary rocks exposed on-land, reworking by currents, distance offshore, biogenic productivity, and reef building. Shelf sediments in the southern Red Sea and off southern Oman are mostly coarse-debris produced by coral reefs and shell-forming macro-organisms and fine-grain carbonate sand and mud from algae and foraminifera. Bottom currents driven by tides, winds, and density differences sort and redistribute sediment, break blocks of reefal debris down, and expose hard grounds. The shorelines of the Gulfs of Suez and Aqaba are tectonically rising producing steep exposures of soft sedimentary strata and Neogene volcanic deposits. Eroded sedimentary and volcanic debris is much more common here than in the Red Sea. Along the north and east shore of the Gulf of Oman, muds are the most common sediment type, while sands of both terrigenous and biogenic origin are found in water depths less than 10 m.