Stratigraphic evidence for an early collision between northwest India and Asia
| Autor: | Gregory W. Riley, Douglas W. Burbank, William J. Sercombe, Jamil Afzal, Jeffrey K. Barndt, Amjed Cheema, John R. Berry, Richard A. Beck, Robert D. Lawrence, Asrar M. Khan, Nasseer A. Shafique, Hermann Jurgen, Jörgen Metje, M. Asif Khan |
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| Rok vydání: | 1995 |
| Předmět: | |
| Zdroj: | Nature. 373:55-58 |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/373055a0 |
| Popis: | THE collision of India with Asia1 had a profound influence on late Cretaceous and Cenozoic oceanography2, climate3, fauna! extinctions4 and the motion of at least some of the Earth's litho-spheric plates5. As the collision ended a period of rapid Indo-Asian convergence6, a precise knowledge of its timing (when the crust of the neo-Tethys ocean was completely subducted7, at some point along the plate boundary) is important for understanding its wider consequences. But current estimates of the collision age range from 65 to 38 Myr before present6, 8–11. Here we report the results of extensive biostratigraphic analyses from Waziristan and Kurram in northwest Pakistan, which show that accretionary-prism and trench strata were first thrust onto the northwest Indian passive margin after 66 Myr but before 55.5 Myr. After this time, volcanic-arc fragments, the accretionary prism, trench material and imbricates of the north Indian slope were raised to shallow water depths and overlapped by upper Palaeocene shallow-water carbonates and shales12–14, indicative of post-collision thrusting in this region. Finally, both the suture and the Indian craton were overlapped by continuous unconformable upper Lower Eocene shallow-marine strata, demonstrating that suturing was complete by 49 Myr. |
| Databáze: | OpenAIRE |
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