A New Model of the Ninety East Ridge Formation, Indian Ocean

Abstract

The comprehensive analysis of geological, geophysical, and geochemical data makes it possible to obtain the most complete picture of the geological structure of the central part of the Ninety East Ridge (NER), the Osborn Plateau, and the adjacent part of the Central Basin. This region has been established to be a complex tectonic structure. In respect of the revealed structural features of the major near-NS faults of Indrani, Indira, and Lanka, they are not transform faults. Based on the generalization of all available data on the northern and southern parts of the NER, supplemented by the studies of the NER’s central part, it is found out that the NER was constructed on the continental crust of an ancient continent, likely Lemuria. According to a new formation model, the NER is a relict fragment of this continent, preserved in the form of a block or an escarp, as an extended horst structure. This paper involves the primary data obtained by different Russian scientific and production organizations in the course of expeditions in the Central Basin during the 1980–1990s, as well as other data, including those obtained from foreign sources.