Abstract
The mainly Mesozoic Hamrat Duru Group represents deep-water, primarily continental rise Neo-Tethyan sediments derived from the Oman continental margin and later emplaced onto the Arabian carbonate platform during the Late Cretaceous obduction of the Semail ophiolite. Sediment patterns reflect fluctuations in sea level relative to the platform, with carbonate input dominant during periods of platform stability. High and low sea-level stands, controlled by eustacy or tectonism, were accompanied by significant reductions of carbonate production and input into the basins. Raised calcite compensation depths associated with high sea levels resulted in the deposition of cherts whereas, during low stands, terrigenous clastics prograded across or by-passed the platform into the Hawasina basin. The Hawasina basin was divided into two sedimentary basins separated by a submarine high. The shale-rich ‘Al Ayn sub-basin’ contained coarse-grained sediments that formed either small fans, or laterally coalescing sediment bodies that were fed by multi-source input of carbonate and terrigenous clastics. This is preserved as the Hamrat Duru Group of the northern and central Oman Mountains. The carbonate-rich ‘Duru sub-basin’ was fed exclusively from the south and large sediment bodies with sheet-like morphologies extended northwards parallel to the margin, outboard from the Al Ayn sub-basin, with thinning and fining trends to the NW and NE. Duru basin units are found in the central and southern Oman Mountains. Contrasting sedimentation patterns in the Al Ayn subbasin and the Duru sub-basin may reflect the influence of prevailing SE trade winds on the margin.