Oh Shenandoah! 80,000 Years of Climate Change in Virginia’s Great Valley

Mendenhall Postdoctoral Research Seminar and 

Eastern Geology and Paleoclimate Science Center Seminar

Benjamin Hardt – USGS, Reston, VA

When: Tuesday, May 13, 2014 – 12 Noon

Where: National Center, Room 1C400 (Visitor Center)


Oh Shenandoah! 80,000 Years of Climate Change in Virginia’s Great Valley

Rapid climate change events such as the Younger Dryas, Dansgaard-Oeschger (D/O) events and Heinrich stadials are a prominent feature of climate during the last glacial period. Corresponding to large temperature changes in Greenland and the North Atlantic, these abrupt shifts have notable consequences for European temperatures, the Asian summer monsoon, and South American precipitation. Very little is yet known about the extent of variability associated with these events in the eastern United States.  A precisely dated record from two stalagmites collected from Grand Caverns in Grottoes, Virginia, provides strong evidence of the Younger Dryas and earlier D/O events impacting the eastern United States.  While these events may be associated with regional temperature change, the stalagmite record likely represents a more direct response to changes in the composition of annual recharge. Available drip water data indicate minimal seasonal variability in δ18O, suggesting mixing times of ~12 months or longer. Changes in the seasonal balance of precipitation between winter- and summer-dominated regimes could explain the observations, although additional study is needed. The strong expression of millennial events in δ18O from the Grand Caverns stalagmites demonstrated by wavelet analysis of the time series contrasts with results from West Virginia, which show minimal variability at millennial scales, and large changes associated with orbital forcing. The stronger expression of millennial events at Grand Caverns is likely due to its position on the east flank of the Appalachians, allowing a greater contribution of Atlantic moisture, particularly during winter months.


WebEX Info

Topic: Mendenhall/EGPSC Seminar-Ben Hardt
Date: Tuesday, May 13, 2014
Time: 11:30 am, Eastern Daylight Time (New York, GMT-04:00)
Meeting number: 714 367 066
Meeting password: EGPSC

Please click the link below to see more information, or to join the meeting.

Although no login account is required to use Webex to attend
a meeting, you will need to supply your name, email address,
and a meeting password (if provided) to join the meeting.

When it is time to attend the meeting, please visit this link:

Teleconference: At start time of the conference, each location must call one of the dial-in numbers:
From the National Center in Reston, dial internally x4848
From all other USGS/DOI locations, dial 703-648-4848
From nonDOI locations, dial toll free 855-547-8255
The toll free number is provided as a courtesy for use by attendees that are working offsite. This number is blocked at most DOI locations, due to the fact that is it less expensive to dial over FTS. If you are unable to connect with the toll free number for any reason, please use 703-648-4848.

After the voice prompt, please enter the Conference Security Code 88002010 followed by the # key. You will hear a tone confirming that you have successfully joined the conference call. If you weren’t successful, you will hear another voice prompt with instructions.

If you are disconnected for any reason, please dial in again using the instructions listed above.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s