Workshop Report - Ridge 2000 Program

instrumented to record the environmental conditions during
sampling. Contamination of samples with seawater, even from the
small sampler dead volumes, presently precludes a number of key
measurements. Chemical sensors and procedures for making
in situ measurements need to be developed, both for documenting
temporal variability of active vents and to provide data free of
artifacts introduced by continued reaction within discrete
samplers.
Strategy
We advocate a balanced, three-pronged, simultaneous approach
in the fi rst stages:
1. Exploration, a continued search for new and varied
hydrothermal systems in a wide suite of geological environments,
including island arc and back-arc terrains.
2. Development of new sampling tools, chemical sensors and
laboratory measurement techniques needed for the investigation
of diverse physical and chemical processes, together with
improvements in forward modeling and inversion techniques. New
tool development should include both deep and shallow drilling
capabilities for a high temperature environment.
3. Initial deployment of instrumentation to make temporal
measurements at specific vents and characterize the principal
processes. These are essential as a guide in organizing future
experiments, and devising new sensor technologies and
approaches.
We are in the initial stages of exploration for active
hydrothermal systems, and already have discovered several major
seafloor sulfide deposits. We predict that additional exploration
will lead to near-term discovery of seafloor hydrothermal
systems of unprecedented size and intensity, which would not
only produce mineral deposits of potentially economic proportions,
but would also yield major perturbations of the global
geochemical cycle. Other discoveries are likely in back-arc,
island arc, and seamount areas, where the systems will have very
different characters from those of the open oceans. Many major
fossil hydrothermal deposits are in sediment-dominated systems,
and exploration in such areas may be especially interesting.
In parallel with the program of exploration for new systems,
testing of new instruments (chemical and physical sensors) and
of instrumented packages for down-hole and/or long-term deployment
must begin using submersibles, drillship time, ROVs, and
limited-duration bottom moorings. ROVs (remotely operated
vehicles) represent a particularly exciting prospect for undersea
investigation of ridge crest hydrothermal systems. In the
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