The first expedition to search for deep-sea hydrothermal vents along the Mid-Cayman Rise has turned up three distinct types of hydrothermal venting, reports an interdisciplinary team led by Woods Hole Oceanographic Institution (WHOI) in this week's Proceedings of the National Academy of Sciences. The work was conducted as part of a NASA-funded effort to search extreme environments for geologic, biologic, and chemical clues to the origins and evolution of life.
Hydrothermal activity occurs on spreading centers all around the world. However, the diversity of the newly discovered vent types, their geologic settings and their relative geographic isolation make the Mid-Cayman Rise a unique environment in the world's ocean.
"This was probably the highest risk expedition I have ever undertaken," said chief scientist Chris German, a WHOI geochemist who has pioneered the use of autonomous underwater vehicles (AUVs) to search for hydrothermal vent sites. "We know hydrothermal vents appear along ridges approximately every 100 km. But this ridge crest is only 100 km long, so we should only have expected to find evidence for one site at most. So finding evidence for three sites was quite unexpected but then finding out that our data indicated that each site represents a different style of venting one of every kind known, all in pretty much the same place was extraordinarily cool."
The Mid-Cayman Rise (MCR) is an ultraslow spreading ridge located in the Cayman Trough the deepest point in the Caribbean Sea and a part of the tectonic boundary between the North American Plate and the Caribbean Plate. At the boundary where the plates are being pulled apart, new material wells up from Earth's interior to form new crust on the seafloor.
The team identified the deepest known hydrothermal vent site and two additional distinct types of vents, one of which is believed to be a shallow, low temperature vent of a kind that has been re
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Woods Hole Oceanographic Institution