Scientists Trace Boundaries of Ancient Texas Lake

FOR IMMEDIATE RELEASE
DATE: May 3, 2006
CONTACT: Norman Martin, (806) 742-4108; norman.martin@ttu.edu

LUBBOCK – Using traces of a rare band of minerals buried more than eight stories below current ground level, Texas Tech University researchers are mapping the boundaries of a massive hyper-saline lake system that swept across the South Plains and well into New Mexico some 1.6 million years ago.

The scientists believe a chain of lakes, which likely ranged more than a mile wide in spots, began near Lubbock’s Yellowhouse Canyon and ended in Fort Sumner, N.M., about 160 miles to the west. They know this by the special mineral and sediments that formed at the bottom of the lake.

Discovering the dimensions of the ancient lakes contributes to a better understanding of what occurred in the past.

“Knowing more about the lakes will help us put some dates on sediments that we didn’t know were there,” said Wayne Hudnall, a soil scientist and Tech’s B. L. Allen Endowed Professor of Pedology. Pedology is the study of soils and soil formation. “It also gives us some information on the climatic conditions for this area during that time.”

During the lake’s formation, volcanic ash and dust were blown onto the water surface, he said. As the material drifted downward through the water, a chemical reaction occurred, separating the material into specific and identifiable minerals.

These minerals – sepiolite, birnessite and calcite – settled on the lake bed as layers.

“It was a chemical reaction that created these minerals, rather than sediments falling into the lake that formed these bands,” Hudnall said. “The deepest we’ve found these bands are 80 feet in a caliche mining pit near Muleshoe, but the lake could have been far deeper. That’s just how far down we’ve gone now.”

The actual dimensions of the lake are still being determined, but Hudnall and doctoral candidate Dusten Russell believe the lakes lie within what’s known as the Portales Basin. Following what was originally a river bed, the lake’s long and narrow form was determined by the basin’s shape.

“It’s not likely the lake would have widened over time,” Russell said. “Just like a stream, the moving water would down cut, rather cut out the sides of the bank.”

There are economic benefits from discovering the lake’s boundaries, too.

“The unique minerals that formed at the bottom of the lakes are now being mined,” he said. “The rock itself is being removed and crushed for use in road construction and in area dairies.”

While the material looks like the typical caliche used on the region’s unpaved roads, the rock coming from the lake beds contains sepiolite, a fibrous mineral that can absorb organic compounds. It also has color advantages, since it is a bright white.

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Contact: Wayne Hudnall, B. L. Allen Endowed Professor of Pedology, Department of Plant and Soil Science, (806) 742-4490; wayne.hudnall@ttacs.ttu.edu