Ibri–Wadi Hawasina–Rustaq

Abstract

The Hawasina Window is a large anticline that forms the northwestern extension of the Jebel Akhdar anticline (Fig. 9.1). The shelf carbonates of Jebel Akhdar form a giant, slightly asymmetric anticline with the fold axis plunging gently WNW beneath the Hawasina Window. The overlying Semail ophiolite has been folded around the anticline and crops out around the window on all sides. The Hawasina Window exposes all allochthonous units beneath the ophiolite and above the shelf carbonates. Haybi complex rocks around the margin consist of metamorphic sole, Oman Exotic limestones, Haybi volcanics and deep-water sedimentary rocks. Two of the largest and most impressive Exotics include Jebel Misht and Jebel Kawr, along the southwest flank of Jebel Akhdar. The Hamrat Duru Group rocks exposed around Jebel Milh show three large-scale fold-nappes, all backfolded, facing to the north. The structurally deepest parts of the Hawasina Window show shelf slope-margin facies Sumeini Group limestones intensely folded and thrust at Jebel Rais, Jebel Rastun and Jebel Mawq. This chapter includes the geological sites around the Hawasina Window and around the northern and southwestern margins of the Jebel Akhdar massif.