May Speaker: "What, Where, How, & Effects of the Chesapeake Bay Impact Structure" by David Powars

by Cindy Schmidtlein, MSDC Vice President for Programs

Our speaker for May, David Scott Powars, will talk to us about an event that occurred about 35 million years ago when an asteroid about two miles in diameter and traveling at tens of thousands of miles per hour slammed into the Atlantic Ocean that covered eastern Virginia, cut through hundreds of feet of seawater and sediments, and blasted an 2-mile-wide crater to a depth of 5 miles within the rocks below the sediments.

Mr. Powars worked for nearly 40 years with the U.S. Geological Survey and authored and coauthored more than 70 publications focused on surficial and subsurface geological maps across the mid-Atlantic Coastal Plain. His career spans over 28 years with the Geological Division and 10 years with the Water Resources Division.

He has presented over 200 lectures and received from the Virginia Museum of Natural History the Thomas Jefferson Award for outstanding contributions to our knowledge of the Virginia Coastal Plain. He also received the Matthew Fontaine Maury award for being an editor and one of the authors of the “Geology of Virginia” volume. He received a B.S. in Biology in 1979 from George Mason University and received his M.S. in Geology in 1988 from George Washington University. As a Research Geologist he has worked on a variety of different projects that range from the bedrock and surficial geological mapping in MT, MA, and CT to earthquake studies in the southeastern U.S., to Coastal Plain studies from the Gulf of Mexico to the mid-Atlantic states.

Mr. Powars was the principal discoverer of the largest impact crater in the U.S., the Chesapeake Bay Impact Crater. This discovery grew out of his research in 1986-87 about a chaotic mixture of various-aged clasts being buried in a steep walled semi-circular basin across a broad area that he thought might be the result of an extraterrestrial impact. These efforts ultimately led to securing funds from the International Continental Drilling Program to drill a very deep (planned 2.3 km, accomplished 1.7 km depth) borehole into the central moat of the crater. This drilling project attracted a wide variety of scientists from around the world who worked on an equally wide variety of investigations.