The eastern margin of the vast Mesozoic carbonate platform which underlies much of Arabia is exposed in the mountains of Oman and the United Arab Emirates. Outer platform and margin facies occur as autochthonous windows in the Oman Mountains and as allochthonous terrane in the Musandam Mountains to the north. These strata are in turn surrounded by westward-thrust nappes of contemporaneous deep-water strata and oceanic lithosphere.

Inundation or drowning of the platform occurred in earliest Cretaceous time and is reflected by Jurassic reef limestones overlain directly by Lower Cretaceous pelagic carbonates. In Oman the outer platform strata are buried by over 250 m (820 ft) of these radiolarian lime mudstones. The abrupt upward transition in middle Cretaceous time to ooid grainstones and then muddy fossiliferous limestones interbedded with rudist biostromes documents buildup to sea level and eastward progradation of first high-energy facies and then lower energy interior facies. In the Musandam Mountains to the north, however, where the Jurassic margin proper was drowned, deep submergence was accompanied by flexure and the Lower Cretaceous limestones are slope deposits as indicated by numerous turbidites, debris flows, and slope unconformities. These strata are also transitional upward into shallow water facies so that by Middle Cretaceous time the high-energy facies were once more at the shelf edge.

These events, which are reflected along the length of this extensive continental margin, occurred during a time of apparant eustatic sea level rise.

End_of_Article - Last_Page 549------------