LAS LOOKING GLASS

How does Earth & Environmental Science Professor Carol Stein find heat on a cold seafloor?

Carol A. Stein's research involves dropping a long spear from a ship to the deep seafloor miles below to measure heat leaking from the solid rock to the water above. “It’s hard to believe,” she says, “but this is one of our best ways to understand how the solid earth works and how it influences the chemistry of the oceans and atmosphere. Cold seawater flows down into the rock, exchanges chemicals, and returns to the oceans. It’s hard to track the flow of water directly, so we put a probe into the seafloor and figure out how much water is moving from the temperature changes it causes.

"Friends and I have been working for several years in a region about the size of Connecticut in the Pacific Ocean near Costa Rica. The sea floor, some two miles below, has about 10 widely separated outcrops sticking out through sediment-covered crust. From about 350 heat flow measurements (indicated by the solid color circles on the figure) made during two one-month cruises, we found that an isolated outcrop releases about as much fluid and heat as one of the high-temperature “black-smoker” vent fields found where new volcanic-rock seafloor is formed at mid-ocean ridges.

Carol Stein and Rob Harris of Oregon State

Finding so much water movement so far from the ridges was surprising. It's like finding Old Faithful in Illinois. It shows that we still have much to learn about the oceans."

The findings were reported in the September 2008 issue of Nature Geoscience. Other key authors of the letter include Andrew Fisher of the University of California, Santa Cruz, and Robert Harris of Oregon State University. The lead author is Michael Hutnak, now with the U.S. Geological Survey. Funding for the project came from the National Science Foundation.

Carol A. Stein (PhD, Columbia University) is a professor of earth and environmental sciences whose research covers a range of topics in plate tectonics dealing with the thermal and mechanical evolution of the lithosphere. These studies use a variety of data and modeling approaches, with primary emphasis on measurements of heat flow at the sea floor.

References:

Hutnak, M., Fisher, A.T., Harris, R., Stein, C., Wang, K., Spinelli, G., Schindler, M., Villinger, H., and E. Silver, Large heat and fluid fluxes driven through mid-plate outcrops on ocean crust, Nature Geoscience, 1, 611-614, doi:10.1038/ngeo264, 2008.