The ultraslow-spreading Southwest Indian Ridge （SWIR） to the east of the Melville fracture zone is characterized by very low melt supply and intensive tectonic activity. Due to its weak thermal budget and extremely ...The ultraslow-spreading Southwest Indian Ridge （SWIR） to the east of the Melville fracture zone is characterized by very low melt supply and intensive tectonic activity. Due to its weak thermal budget and extremely slow spreading rate, the easternmost SWIR was considered to be devoid of hydrothermal activity until the discovery of the inactive Mt. lourdanne hydrothermal field （27°51＇S, 63°56＇E） in 1998. During the COMRA DYl15-20 cruise in 2009, two additional hydrothermal fields （i.e., the Tiancheng （27°51＇S, 63°55＇E） and Tianzuo （27°57＇S, 63°32＇E） fields） were discovered. Further detailed investigations of these two hydrothermal sites were conducted by Chinese manned submersible liaolong in 2014-2015. The Tiancheng filed can he characterized as a low- temperature （up to 13.2℃） diffuse flow hydrothermal field, and is hosted by fractured basalts with hydrothermal fauna widespread on the seafloor. The Tianzuo hydrothermal field is an inactive sulfide field, which is hosted by ultramafic rocks and controlled by detachment fault. The discovery of the three hydrothermal fields around Segment #11 which receives more melt than the regional average, provided evidence for local enhanced magmatism providing heat source to drive hydrothermal circulation. We further imply that hydrothermal activity and sulfide deposits may be rather promising along the easternmost SWIR.展开更多
基金The National Key Research and Development Program of China under contract Nos 2017YFC0306603,2018YFC0309901,2016YFC0304905,2017YFC0306803 and 2018YFC0309902the China Ocean Mineral Resources Research and Development Association Major Project under contract Nos DY135-S1-1-01 and DY135-S1-1-02
文摘The ultraslow-spreading Southwest Indian Ridge （SWIR） to the east of the Melville fracture zone is characterized by very low melt supply and intensive tectonic activity. Due to its weak thermal budget and extremely slow spreading rate, the easternmost SWIR was considered to be devoid of hydrothermal activity until the discovery of the inactive Mt. lourdanne hydrothermal field （27°51＇S, 63°56＇E） in 1998. During the COMRA DYl15-20 cruise in 2009, two additional hydrothermal fields （i.e., the Tiancheng （27°51＇S, 63°55＇E） and Tianzuo （27°57＇S, 63°32＇E） fields） were discovered. Further detailed investigations of these two hydrothermal sites were conducted by Chinese manned submersible liaolong in 2014-2015. The Tiancheng filed can he characterized as a low- temperature （up to 13.2℃） diffuse flow hydrothermal field, and is hosted by fractured basalts with hydrothermal fauna widespread on the seafloor. The Tianzuo hydrothermal field is an inactive sulfide field, which is hosted by ultramafic rocks and controlled by detachment fault. The discovery of the three hydrothermal fields around Segment #11 which receives more melt than the regional average, provided evidence for local enhanced magmatism providing heat source to drive hydrothermal circulation. We further imply that hydrothermal activity and sulfide deposits may be rather promising along the easternmost SWIR.
