Petrology of the Ninety East Ridge (Indian Ocean) compared to other aseismic ridges |
| |
| Authors: | Roger Hekinian |
| |
| Institution: | 1. Centre Océanologique de Bretagne, F-29273, Brest, France
|
| |
| Abstract: | The volcanics from the Ninety East Ridge in the Indian Ocean consist of basalts and oceanic andesites. The basalts from the Ninety East Ridge differ from the Mid-Indian Oceanic Ridge basalts in their higher pyroxene content, their higher Fe2O3 + FeO content (>11%), higher TiO2 content (2–3%), and variable K2O content (0.2–1.5%). Volcanics from other aseismic ridges, i.e. the Cocos, the Iceland-Faeroe and the Walvis ridges, show a trend of differentiation which has progressed further than is commonly encountered on mid-oceanic ridge rocks. The Ninety East and the Iceland-Faeroe ridges contain mildly tholeiitic basalts and oceanic andesites while the Walvis and the Cocos Ridges consist of plagioclase-alkali basalts, trachybasalts and trachytes. The majority of basalts found on aseismic ridges have a higher total iron oxide content (>11%) and a more variable K2O (2–3%) and TiO2 (1.5–4%) content than mid-oceanic ridge basalts. The type of volcanism encountered on aseismic ridges is similar to that of the islands which are near or associated with the ridges. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
