text-only page produced automatically by LIFT Text Transcoder Skip all navigation and go to page content Skip top navigation and go to directorate navigation Skip top navigation and go to page navigation
National Science Foundation
design element
Search Awards
Recent Awards
Presidential and Honorary Awards
About Awards
Grant Policy Manual
Grant General Conditions
Cooperative Agreement Conditions
Special Conditions
Federal Demonstration Partnership
Policy Office Website

Award Abstract #0214525

Varved Records of Decade- to Century-Scale Climate Variability in the Tropical Atlantic Sector

Division of Atmospheric and Geospace Sciences
divider line
Initial Amendment Date: July 29, 2002
divider line
Latest Amendment Date: July 29, 2002
divider line
Award Number: 0214525
divider line
Award Instrument: Standard Grant
divider line
Program Manager: David J. Verardo
AGS Division of Atmospheric and Geospace Sciences
GEO Directorate for Geosciences
divider line
Start Date: August 1, 2002
divider line
End Date: July 31, 2005 (Estimated)
divider line
Awarded Amount to Date: $167,000.00
divider line
Investigator(s): Jonathan Overpeck jto@email.arizona.edu (Principal Investigator)
J. Warren Beck (Co-Principal Investigator)
divider line
Sponsor: University of Arizona
888 N Euclid Ave
TUCSON, AZ 85721-0001 (520)626-6000
divider line
divider line
Program Reference Code(s): 1304, EGCH
divider line
Program Element Code(s): 1577


This award is to analyze sediments from Lake Bosumtwi to generate a record of tropical West African hydrologic variability back to 3000 years with decadal resolution. In addition, the first tropical record of atmospheric radiocarbon change between 10,000 and 25,000 years will be produced.

Previous field work has secured laminated core material back to about 25,000 years at Lake Bosumtwi. A variety of proxy indicators of climate will be analyzed from these sediments to produce a paleohydrologic time series. Charcoal from terrestrial plants will be dated from the varved layers to generate a D14C calibration curve for radiometric dating.

The timing of droughts and the natural variability of droughts to this region (West Africa) are important. Better understanding of how the hydrologic history of the region relates to similar records from other regions will advance our overall knowledge of the climate system and allow us to answer many questions regarding interrelationships between low and high latitude and marine and terrestrial climate interactions. The true shape of the atmospheric radiocarbon variation during glacial to deglacial times will be an important advancement for radiocarbon dating.


Shanahan, T.M., Overpeck, J.T.
and Beck, J.W.. "Reconciling in-situ cosmogenic
36Cl production rate estimates", 08/01/2002-07/31/2005, "American Geophysical Union
2002 Fall Meeting."
,  2002, "none".

Shanahan, T. M., Overpeck, J. T.,
Hughen, K., Drenzek, N., Beck, J.
W., Peck, J., King, J., Scholz, C.A.
and Wheeler ,C. W.. "Orbital and non-orbital forcing of
hydrologic and vegetation
change in West Africa since the
LGM from geochemical records
and hydrologic modeling of Lake
Bosumtwi, Ghana.", 08/01/2002-07/31/2005, "Geological Society of America
Annual Meeting."
,  2005, "none".

Shanahan, T. M., Overpeck ,J. T.,
Peck J., King, J., Scholz, C.,
Hughen, K., Drenzek, N., and
Beck, J. W.. "Paleoenvironmental changes in
West Africa since the Last Glacial
Maximum from a geochemical
and modeling study of Lake
Bosumtwi, Ghana", 08/01/2002-07/31/2005, "American Geophysical Union
Fall Meeting."
,  2005, "none".

Shanahan, T.M.. "Reconstructing the lake level
history of Lake Bosumtwi, Ghana,", 08/01/2002-07/31/2005, "International Limnological
Conference, Tucson"
,  2003, "none".

Wheeler C. W., Overpeck W.,
Arko J., and Sharp W. E.. "The Varved Sediments
of Lake Bosumtwi, Ghana and
Implications for a new
Chronology of West African
Hydrologic Change during the
Late Quaternary.", 08/01/2002-07/31/2005, "American Geophysical Union
,  2002, "none".

Tim Shanahan. "West African climate dynamics
and paleoenvironmental change
from the varved sediments of Lake Bosumtwi, Ghana
sediments of Lake Bosumtwi,
Ghana", 08/01/2002-07/31/2005,  2006, "in prep.".


Please report errors in award information by writing to: awardsearch@nsf.gov.



Print this page
Back to Top of page
Research.gov  |  USA.gov  |  National Science Board  |  Recovery Act  |  Budget and Performance  |  Annual Financial Report
Web Policies and Important Links  |  Privacy  |  FOIA  |  NO FEAR Act  |  Inspector General  |  Webmaster Contact  |  Site Map
National Science Foundation Logo
The National Science Foundation, 4201 Wilson Boulevard, Arlington, Virginia 22230, USA
Tel: (703) 292-5111, FIRS: (800) 877-8339 | TDD: (800) 281-8749
  Text Only Version