LATE CRETACEOUS/EARLY TERTIARY CONVERGENCE BETWEEN THE INDIAN AND ARABIAN PLATES RECORDED IN OPHIOLITES AND RELATED SEDIMENTS

摘要: Abstract Remnants of ocean floor forming the Eastern Ophiolite Belt in Oman and Western Pakistan have a common plate-tectonic history culminating emplacement at Cretaceous/Tertiary boundary. Fragments these two belts ages between 150 65 Ma recorded tectonic events early Indian Ocean Ma, 130-120 110-100 70-65 Ma. New radiometric chronostratigraphic paleomagnetic sedimentary information are used to relocate ophiolites frame evolving Ocean, which was characterised by stepwise breakup Gondwana 158 (East West Gondwana), 130 (Southern Atlantic, East 95-84 (Madagascar India/Seychelles), (India Seychelles) and, finally, 40 rifting Africa Arabia. The 150-Ma-old oceanic rocks Masirah Island originally formed extension basins now preserved along eastern edge Afro-Arabian plate. drifted together with India-Seychelles when new ridge approximately separating microplates (e.g., Kabul Block) from northern Greater India. Parts this were later emplaced form western ophiolite belt Pakistan. Consumption crust during closure Neotethys occurred not only north India (± Seychelles), but also or three subduction zones plate India/Seychelles, documented formation metamorphic soles beneath ophiolites. Relics 65–70 ago, upper units where they overlie an accretionary prism pillow lavas dominantly (Aptian-) Albian age rocks. Seychelles associated eruption flood basalts (Deccan enhanced counter-clockwise movement This possibly caused Late Jurassic/Early Cretaceous fragments Masirah) be thrust onto Oman. ophiolites, India, as part farther collision Eurasia accreted Eocene (∼ 55 Ma).