Advances in Slow-Ultraslow-Spreading Southwest Indian Ridge

Southwest Indian Ridge(SWIR) is characterized by slow-spreading to ultraslow-spreading rate and oblique spreading,which reveals an ultraslow-spreading class of ocean ridge.Recently,SWIR has becoming one of hotspots researching on the global mid-ocean ridge systems and also the important region for the study of seafloor tectonic setting,hydrothermal activity,deep process of mantle and its dynamic mechanism.This review summarizes study history,morphologic and structural characteristics,hydrothermal activity and geochemical characteristics of basalt and peridotite in on SWIR.The particularity of both ultraslow spreading ridge and ultramafic hosted hydrothermal system are discussed.The ultraslow and oblique spreading can contribute to generating peridotite and serpentite on ultraslow spreading ridges as well as ultramafic-hosted hydrothermal system related to the exothermic serpentinization reactions,which is different from traditional basalt-hosted hydrothermal system.The more hydrothermal activity and the slower spreading rate may lead to the deposition of larger ore bodies due to their localization on long-lived fault structures on SWIR.Therfore,Mantle mantle rocks exposed widely and its serpentinization,ultramafic hosted hydrothermal system and mineralization of hydrothermal sulfide are proposed as the important future avenue of research in on SWIR.