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Evidence Presented in Toronto... Meteorite Impact Formed Chesapeake Bay Impact Crater Controls Region’s Groundwater Flow and Quality
Released: 10/24/1998

Contact Information:
U.S. Department of the Interior, U.S. Geological Survey
Office of Communication
119 National Center
Reston, VA 20192
Diane Noserale 1-click interview
Phone: 703-648-4333, In Toronto: 416-585-3706 | FAX: 703-648-6859




A large meteorite plummeted into the western Atlantic Ocean about 35 million years ago, creating the 120-km wide Chesapeake Bay impact crater [Geology (Boulder), 22 (8), p. 691-694]. This event and its aftermath, which continues to this day, will be presented by U.S. Geological Survey geologist Dr. David S. Powars at the Annual Meeting of the Geological Society of America scheduled for Oct. 25-29 in Toronto, Canada.

"The impact penetrated the entire coastal plain sedimentary sequence and at least 2 km of basement rock," says Powars. "Subsequently, the crater was filled with the deposits of rock fragments and seawater, and then buried beneath recent marine sediments. The resulting crater has an inner and outer rim, a relatively flat-floored annular trough, and an inner basin with a central uplift and surrounding concentric ridges and valleys. These structural and stratigraphic features control regional ground-water flow, and the outer rim serves as a boundary separating the inner higher salinity water from the freshwater to the west," Powars explained.

"Stratigraphic, Structural, and Hydrogeological Complexities Related to the Outer Rim of the Chesapeake Bay Impact Crater" (poster) is scheduled for 1:30 -5:30 pm Wednesday, Oct 28 Metro Toronto Convention Center Hall-E.


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