Sea-level study of Chesapeake Bay & Evidence of an Impact 35 Million Years Ago

A few weeks ago, I wrote a post about sea-level rise.  Well, here’s a quick update to start the week (albeit a day or so late) on that same subject, but a little closer to home – for me at least. From ScienceDaily, one of my favorite online new sources, comes good and bad news about sea-level rise in the Chesapeake Bay.

ScienceDaily (2010-12-20) — A study of sea-level trends brings both good and bad news to localities concerned with coastal inundation and flooding along the shores of Chesapeake Bay. Dr. John Boon, the study’s lead author, says the good news is that “absolute sea level in Chesapeake Bay is rising only about half as fast as the global average rise rate.” The bad news, says Boon, is that “local subsidence more than makes up for it.”

A really cool fact that I learned from the study is that there is evidence of an impact crater beneath the Chesapeake Bay. The Chesapeake Bay Impact Crater was formed approximately 35 million years ago by the impact of a large meteor or comet near Cape Charles, VA (Poag et al., 1992). I’ll definitely look into that for a possible future post.

Chesapeake Bay Impact Crater
Map showing subsurface extent of the Chesapeake Bay Impact Crater. From Boon et al., 2010

The whole report “Chesapeake Bay Land Subsidence and Sea Level Change: An Evaluation of Past and Present Trends and Future Outlook “is available as a .pdf here.

[Note: the study was commissioned by the Army Corp of Engineers, and reviewed by the National Oceanic and Atmospheric Administration, and the Maryland Geological Survey, but it was not peer-reviewed.]

References:

Boon, J.D., J. M. Brubaker, and D. R. Forrest. “Chesapeake Bay Land Subsidence and Sea Level Change, An Evaluation of Past and Present Trends and Future Outlook: A report to the U.S. Army Corps of Engineers Norfolk District.” Virginia Institute of Marine Science Special Report No. 425 in Applied Marine Science and Ocean Engineering. November 2010

Poag, C.W., Powars, D.S., Poppe, L.J., Mixon, R.B., Edwards, L.E., Folger, D.W., and Bruce, S., 1992. Deep Sea Drilling Project Site 612 bolide event—new evidence of a late Eocene impactwave deposit and a possible impact site, U.S. east coast: Geology, 20: 771-774.

Virginia Institute of Marine Science (2010, December 20). Sea-level study brings good and bad news to Chesapeake Bay. ScienceDaily. Retrieved December 21, 2010, from http://www.sciencedaily.com­ /releases/2010/12/101221101922.htm#

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