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NMSU geologist studies earth's structural changes

Katherine Giles wants to better understand why salt structures formed and how they behave through time. The New Mexico State University geologist says the knowledge is important to help determine the best places to drill for oil traps and the safest methods for storing contaminated nuclear materials.



Kate Giles, director of NMSU's Institute of Tectonic Studies, takes a break while out in the field in Nevada.

Salt structures, which commonly occur where the earth's crust has been pulled apart, are found in many areas around the world, Giles said. "Yet we know very little about salt and its behavior."

Giles, director of NMSU's Institute of Tectonic Studies, and her research team have been studying salt structures in an area called La Popa Basin, located about 20 miles northwest of Monterrey, Mexico, for almost four years.

At La Popa Basin there are outcroppings of salt structures normally found thousands of feet under the sea or in the earth's subsurface. "It's one of the few outcroppings in the world, and arguably the best example for scientific research," Giles said. "It's new for us to be able to walk around and look at them."

The basin, which covers a 350-square-mile area, contains two small salt stocks, or vertical tubes of salt, Giles said. Her team has focused on these structures to analyze the rock types around them and their relationship to the salt stocks.

During that process, the team discovered a salt weld. "This is an area where there used to be a huge wall of salt," Giles explained. "The salt migrated from the area, and the adjacent rocks collapsed together to fill the remaining void."

Giles said this is the only surface exposure of a salt weld that experts are aware of, so at this point they are poorly understood. She hopes to find out how it got there and what happened to it, to help answer the question of why salt moves. "Not all salt moves," she said. "But when it does, it often generates stocks and welds. These are important areas where oil is found."

A better understanding of the behavior of salt will help oil companies know the best places to drill, Giles said. It reduces their risks and the impact on the environment that results from drilling in the wrong places. For that reason her research is backed by a consortium of eight oil companies.

Giles was recently awarded a combined Fulbright-Garcia Robles Scholarship for Mexico in the Science and Technology Division to expand her research in the La Popa Basin. About two such awards are given nationally each year. She will travel to Mexico City to teach several short courses at the Universidad Nacional Autonoma de Mexico (UNAM), and she will lead a joint UNAM/NMSU field excursion to conduct research at La Popa Basin. She will be in Mexico City from June 1 to Sept. 1, 2001.

Her research in La Popa Basin is one of several projects supported by the recently created Institute of Tectonic Studies. Tectonics is the study of the earth's crustal structure and the forces that produce changes in it. Other projects funded by the institute are under way in New Mexico, Nevada and Alaska.

The institute helps fund tectonics research by serving as an umbrella organization, directing money to fund faculty and student research that otherwise might not be funded through traditional means. One of the goals of the institute is to build up the expertise of NMSU's faculty and students in the area of tectonic studies, Giles said.

The institute also is able to employ undergraduate students to work on projects directly involved with geology, she said. Students learn skills they don't necessarily get in class, including state of the art geological computer modeling programs and Geographical Information Systems software.

"It gives students a great background to go into industry," she said. "They just need experience, and they learn the most by actually doing it."