Miocene volcanism of the Ninetyeast Ridge

Abstract

The East Indian or Ninetyeast Ridge is one of the most unique and enigmatic structures of the oceanic bottom. It is characterized by a linear shape and extends in the meridional direction via the eastern part of the Indian Ocean for almost 5000 km and is approx� imately 200 km wide (Fig. 1). The ridge was discovered in the 1920s and first studied in detail in 1963 during the R/V Vityaz scientific expedition. In subsequent years, geological–geophysical studies of the ridge were conducted in cruises of research vessels from the Shir� shov Institute of Oceanology, RAN [1] and other Rus� sian and foreign scientific organizations. Most of the geological–geophysical data were obtained there in the 1970s–1980s.Since that time, the scientific equip� ment and study methods have become substantially better. Despite the sufficient knowledge of the ridge structure owing to numerous oceanological expedi�