The overall aim of Leg 193 is to determine the subsurface volcanic architecture, the structural and hydrologic characteristics, and the deep-seated mineralization and alteration patterns of the Manus hydrothermal field.

The Manus Basin is a rapidly opening (~10 cm/yr) backarc basin set between the Manus Trench and New Britain Trench. It lies within the zone of convergence between the major Indo-Australian and Pacific plates.

The host rock is siliceous volcanic (dacite) rather than the more typical basalt. Its massive sulfide chimneys are particularly rich in copper and gold.

Major active hydrothermal sites (stars) at convergent margins of the western Pacific Ocean. Large arrows indicate general plate motion directions

(Leg 193 Scientific Prospectus, Ocean Drilling Program , College Station, TX.)