Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: TUESDAY, September 6, 1994                   TAG: 9409080021
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A-4   EDITION: METRO 
SOURCE: Associated Press
DATELINE: BALTIMORE                                LENGTH: Medium

BAY BELIEVED FORMED BY A METEORITE

Wylie Poag and three colleagues with the U.S. Geological Survey reported in the August edition of the journal Geology that they found a 50-mile-wide, mile-deep crater at the mouth of the Chesapeake Bay.

If scientists confirm that geologic feature is the crater from a meteorite impact, it would be the sixth-largest of the earth's known meteorite craters and the largest ever found in the United States.

Over the past 35 million years, the crater acted like the drain in a bathtub when sea levels were low, giving the region's rivers a single outlet to the ocean, Poag said. When sea levels rose in warmer periods, Poag said, those low-lying river channels were inundated, creating the bay's broad, shallow waters.

There is evidence that a smaller object hit the ocean 90 miles off Atlantic City, N.J., 35 million years ago, forming a 10-mile-wide crater.

Both the Chesapeake and Atlantic City craters, Poag speculated, may have been caused by fragments of the same object or a train of objects.

``We're just guessing about that,'' he said.

Poag, who is based in Woods Hole, Mass., began studying the lower Chesapeake in 1990, when he looked at an unusual layer of fragmented and crumbled rocks found in cores drilled on the bay's Virginia shores. This material, he said, indicated some sort of impact. The core samples also contained small amounts of quartz and other mineral crystals that had been placed under tremendous heat and pressure.

Scientists think these ``shocked'' quartzes can be produced only by meteorite collisions.

Poag published an article in 1992 concluding that the layer of shattered rock found off Virginia was formed when a tsunami caused by the impact of the Atlantic City meteorite smacked the East Coast.

He changed his mind, he said, after he studied portions of the seismic profiles of the bay bottom made by Texaco and Exxon, which searched for oil deposits in the lower Chesapeake from about 1989 to 1992.

Richard A.F. Grieve, who studies craters for the Geological Survey of Canada in Ottawa, recently told the publication Science News that Poag and his co-authors David S. Powars, Lawrence J. Poppe and Robert B. Mixon, had not proved they had discovered a new crater.

He said he was still looking through rock samples Poag sent him for signs of shocked quartz.

But Glen A. Izett, a retired geologist with the U.S. Geological Survey and a former colleague of Poag, said Friday he thinks the seismic data strongly suggest a crater-shaped feature lies beneath the sediments on the bay bottom.