Abstract
The process of surveys and researches about a submarine volcano and its hydrothermal ore deposit on the Island Arc is arranged as follows:
1) The detailed submarine topographic survey around the top of many seamounts with a narrow multi-beam echo sounder,
2) The selection of some active submarine volcanoes accompanied by a volcanic crater below 1,000min depth,
3) The geochemical inquiry of the hydrothermal plume,
4) The preliminary survey with a ROV (Remotely Operated Vehicle) and a deep sea camera,
5) The submersible observations and the gathering the volcanic rocks, ores and hydrothermal fluid by the submersible vessel,
6) The mapping the distribution of the volcanic geology and the hydrothermal activity on the sea-floor,
7) The analysis of the gathered volcanic rocks, ores and hydrothermal fluid.
The research about the hydrothermal ore deposits formed on the submarine volcanoes is one of the researches realized as the compilation of the technology developed recently for the sea-floor survey.
As a example of the recent result of some sea-floor surveys by the JAMSTEC 'Shinkai 2000', the discovery of the sea-floor hydrothermal ore deposits at the top of Suiyo Seamount in Sitiyo Seamounts is cited. This hydrothermal gushing is very active, which the highest temperature is 310°C. The sulfides of the vent chimneys from this hydrothermal field are rich in Cu. The highest Au content of sulfide samples is 71 ppm.
