The Indian Promontory: A Bridge between Plate Tectonics and Life Evolution Models
| Autor: | Cyril Hochard, Gilles D. Borel, Gérard M. Stampfli, Christian Vérard |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Universal Journal of Geoscience. 5:25-32 |
| ISSN: | 2331-9615 2331-9593 |
| DOI: | 10.13189/ujg.2017.050202 |
| Popis: | Since the 1970's, the Cretaceous–Cenozoic migration of the India subcontinent is fairly well-established. Seafloor magnetic anomalies in the Indian Ocean allow positioning the subcontinent during this time frame. India broke-up slowly from Antarctica in the Early Cretaceous, speed up (~18-20 cm/year) in the Late Cretaceous, and then slow down (~5 cm/year) in the early Cenozoic, a period for which geologists report the first evidences of the India–Eurasia collision leading to the formation of the Himalayan–Tibetan Orogen. However, fossil records as well as biogeography deduced from molecular phylogeny cast a doubt on the tectonicists' confidence on their palaeopositions, because faunal evidences support India as a 'biotic ferry' from its break-up from Gondwana in the Jurassic and then connectivity between Asia and India as early as the Cretaceous. The two types of observations can be reconciled if an Indian Promontory formed when India separated from Australia and Antarctica. In our plate tectonics model, the Indian Promontory drifted northward together with the Indian plate from the Cretaceous, but collided as early as the Campanian with Eurasia, id est about 40 Ma before the northern margin of 'Greater India' collide and form the Himalayas. The proposed Indian Promontory can therefore solve the paradox of having evidences for early land connectivity between India and Asia, the need of excluding unrealistic 'Greater India' (i.e. 4000-4500 km at ca. 80 Ma), and the need of having a plate tectonic scenario consistent with geological records (subsidence curves, exotic origin of terranes from the promontory), geophysical records (age and structure of the Argo Abyssal Plain), and geodynamical consideration about stress transmission of forces acting at plate boundaries. |
| Databáze: | OpenAIRE |
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