West-northwest directed obduction of the Batain Group on the eastern Oman continental margin at the Cretaceous-Tertiary boundary

The Batain coast area in eastern Oman is dominated by allochthonous Permian to Late Maastrichtian sedimentary and volcanic rocks (Batain Group), uncon formably overlain by neoautochthonous Tertiary sediments. The allochthonous rocks of the Batain coast were previously attributed to the Hawasina compl ex, the Permian to Coniacian/Santonian sedimentary infill of the neo-Tethya n Hawasina basin off northern Oman. Previous structural interpretations sug gested that the Batain Group, along with the Hawasina complex and the Semai l ophiolite, was obducted in the Coniacian to Campanian from NE to SW onto the northern Oman continental margin. Results of our work in the Batain are a differ from previous interpretations, with most significant differences c oncerning timing and direction of obduction, Our results show that WNW dire cted tectonic movements formed a fold-and-thrust belt and led to the obduct ion of allochthonous rocks onto the east Oman continental margin during lat est Maastrichtian/earliest Paleocene times. This is coeval with emplacement of ophiolitic fragments along the eastern coast of Oman (eastern ophiolite bell) but is about 15-20 Myr later than emplacement of Hawasina complex an d Semail ophiolite in northern Oman. Postemplacement structural evolution d uring the Tertiary involved intraplate extension, possibly reflecting the R ed Sea/Gulf of Aden opening, and late Tertiary shortening related to conver gence between Arabia and Eurasia. Late Tertiary contractional deformation r esulted in refolding of the Batain nappes and in folding of the overlying T ertiary sediments. A palinspastic reconstruction of the Batain area indicat es that the Permian to Upper Cretaceous sediments were formerly deposited i n the Batain basin, a part of the proto-Indian Ocean, along the present-day eastern Oman margin. This leads us to propose that Permian breakup of Gond wanaland created both continental margins of Oman and led to the opening of two major basins: the neo-Tethyan Hawasina basin in the north and the prot o-Indian Ocean Batain basin in the east, the latter separating Arabia from greater India.