| Rolland, Y. 2002. From intra-oceanic convergence to post-collisional evolution: example of the India-Asia convergence in NW Himalaya, from Cretaceous to present. In: Rosenbaum, G. and Lister, G. S. 2002. Reconstruction of the evolution of the Alpine-Himalayan orogeny. Journal of the Virtual Explorer. | ||
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From
intra-oceanic convergence to post-collisional evolution:
example of the India-Asia convergence in NW Himalaya, from Cretaceous to present |
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Placed
in Dynamic Review - 15 April 2002
Y. Rolland Abstract The NW part of the Himalayan Orogen (Kohistan, Ladakh and Karakoram, in Pakistan and India) has been investigated to reconstruct the successive stages of convergence of two continents (India and Asia) over the past 110 Ma, from oceanic to post-collisional settings. The intra-oceanic stages of the convergence have been reconstructed from study of the preserved Tethyan Arc series of the Kohistan-Ladakh Terrane. Geochemical and lithological data indicate continuation of the Kohistan intra-oceanic arc in the west into an Andean arc on the Tibetan continental margin in the east. Adakitic and Nb-Ta-Ti rich lavas appear to be present, interlayered with basalts to andesites in the intra-oceanic arc series. Along with major, trace and isotopic (Sr, Nd and Pb) data of basalt to andesite lavas, adakitic magmatism suggests complex interactions between crustal melts and mantle. In the tectonic context of the Neo-Tethys Ocean at 110 Ma, the Kohistan-Ladakh Arc system may have formed following the subduction of the Neo-Tethys mid-oceanic ridge, similar to a model which has been proposed for the initiation of Oman ophiolite obduction. This ocean-ridge subduction could be triggered by the initiation of fast northward drift of India in the Middle Cretaceous period. The post-collisional
evolution comprises two stages:
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Index: Pre India-Asia convergence history (>110 Ma) Review of our present understanding of the India-Asia convergence in NW Himalaya Reconstruction of the India-Asia convergence in NW Himalaya (since 110 Ma)
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