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New Technology for New Exploration of Hydrothermal Vents


December 5, 2005

Advances in undersea imaging systems, the development of new vehicles
and instruments, and improved seafloor mapping capabilities have
enabled scientists to explore areas of the deep sea in unprecedented
detail.  One such area is the TAG hydrothermal mound in the North
Atlantic Ocean, one of the largest known mineral deposits on the
seafloor.

Rob Reves-Sohn , a geologist at Woods Hole Oceanographic Institution (WHOI),
will discuss some of the technological advances and present some recent
imagery collected at the TAG  hydrothermal vent during a 
press conference today at the American Geophysical Union meeting in San
Francisco. TAG, for Trans Atlantic Geotraverse, is on the Mid-Atlantic
Ridge about 1,900 miles east of Miami at 26°8’N and 44°49’W more than
two miles below the ocean’s surface.

Since hydrothermal vents were discovered in 1977 on the Galapagos Rift
in the eastern Pacific Ocean, vent sites have been found on the
mid-ocean ridge around the world.  New sites are found each year,
each with unique animal communities and geological/geochemical
features. TAG was among the first to be found in the North Atlantic 20
years ago.  
    
Using two-dimensional maps produced from data collected by a research
vessel, Reves-Sohn and colleagues produced computer animations of the
TAG site, enabling scientists to view it from different
perspectives.  Images of the mound and smokers were taken by
cameras mounted on the three-person submersible Alvin, operated by WHOI
for the American ocean research community.

For centuries, people have mined copper, gold and precious metals on
land from mineral deposits that many believe formed on the ocean
floor.  At the TAG vent site, a superheated mixture of seawater
and toxic chemicals hot enough to melt lead billows out of the
seafloor. This fluid, driven by heat from molten magma deep below the
earth’s crust, erupts into clouds or plumes that rise nearly 1,000 feet
above the ocean bottom. Chemical reactions occurring as this hot fluid
mixes with cold seawater cause the formation of chimney-like structures
called “black smokers.” These freestanding chimneys, which commonly
reach heights of 100 feet or more, contain minerals similar to those
mined on land.

AGU Press Conference:  Monday, December 5 MC Level 2, Room 2012 3 p.m. PST
Diversity of Hydrothermal Systems at Slow Spreading Ocean Ridges

Related AGU Session:  OS33A-1466 New Constraints on the Thermal Power of the TAG Hydrothermal System and the Dynamics of the Water Column Plume