| Abstract |
Separate hydrothermal systems can be in a variety of ways. Criteria which have been applied include separation of heat source, upflow, economic resource and geophysical anomaly. Alternatively, connections have been defined by the effects of withdrawal of economically useful fluid and subsidence, effects of reinjection, changes in thermal features, by a hydrological connection of groundwaters. It is proposed here that: "A separate hydrothennal system is one that is fed by a separate convective at a depth above the brittle-ductile transitionfor the host rocks, while acknowledging that separate hydrothennal system can be hydrologically interconnected at shallower levels |