The Baer-Bassit area of NW Syria exemplifies the evolution of Neotethys at the W end of the "ophiolitic crescent". The stratigraphy of the Baer-Bassit area is divisible into four main units. 1) At the base, there is a relatively autochthonous Mesozoic Arabian carbonate platform (1500-1800 m thick), of Mid Jurassic-Early Cretaceous age. This is exposed only in the north, as the mountainous Jebel Aqraa massif. Shallow-marine limestones are overlain by Cenomanian-Lower Maastrichtian pelagic carbonates. 2) The Mesozoic carbonate platform is overthrust by deformed Mesozoic rocks of continental margin and oceanic affinities. There is a structurally lower unit of highly deformed volcanic-sedimentary lithologies, ca. 450m thick (Baer-Bassit Melange). Deep-sea sediments and alkaline volcanics of Late Triassic age mark the opening of Neotethys in the Eastern Mediterranean region. Middle Jurassic-Lower Cretaceous volcanics of alkaline composition are interbedded with ribbon radiolarites. Successions continue upwards into Early Cretaceous channalized sandy limestone. Late Cretaceous (Cenomanian) limestone debris flows, calciturbidites and pelagic muds, related to sediment instability along the Arabian passive margin to the south. 3) Structurally above is a complete, but thrust deformed, Upper Cretaceous ophiolitic suite of supra-subduction zone-type, based on geochemical characteristics, that includes plutonics, sheeted dykes and volcanics, the latter similar to the upper pillow lavas of the Troodos ophiolite, Cyprus. Locally, the uppermost extrusives are overlain by Fe-Mn sediments, comparable with the hydrothermal umbers of the Troodos ophiolite, Cyprus. The plutonics are structurally underlain by a well developed metamorphic sole, 200-300m thick, for which the protoliths were mainly alkaline extrusives and associated sediments similar to those within the melange beneath. The entire assemblage of passive margin and ophiolitic units was emplaced onto the Arabian margin in middle Maastrichtian time.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:640319 |
| Date | January 2000 |
| Creators | Al-Riyami, Khalil K. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14725 |
Page generated in 0.0019 seconds