Late Miocene to Present erosion of the Masirah allochthon and its cover based on clay minerals and thermal modeling, Batain area, eastern Sultanate of Oman

The Batain area of easternmost Arabia was overthrust from the ESE by deep-sea basin rocks and the Masirah Ophiolite in the course of left-lateral transpression between Arabia and India during the Cretaceous/Paleogene transition. A ~40 km-wide fold-and-thrust belt covers the Batain area of easternmost Oman. The original thickness of this belt including the Masirah Ophiolite and the post-nappe cover, and the timing of its erosion is largely unknown. We performed X-ray diffraction analyses of deep-water sediments to define the thermal history of the Batain fold-and-thrust belt by constraining its thermal signature, maximum burial conditions and post-nappe development. The shaly Warah and Sal formations record random-ordered, mixed layer illite-smectite (I-S) with an illite content ranging between 30-40%. One-dimensional thermal modeling documents that the Batain area was covered by a ~300 m thick nappe of the Masirah Ophiolite which was eroded immediately after its emplacement during the Danian. Furthermore, the Batain area was uniformly blanketed by ~700 m-thick post-nappe rocks. Erosion of most of these Cenozoic post-nappe rocks and some allochthonous rocks occurred after peak-thermal conditions during the late Miocene. We conclude that the Batain area underwent erosion (erosion rate of 0.06 mm/a) since the Tortonian, due to monsoonal climate conditions combined with regional uplift related to the Arabia-India convergence. The clastic sediments accumulated offshore, eastwards of the Batain area, were massive Neogene to Quaternary sedimentary rocks occur.