My research interests and objectives center upon advancing the knowledge of the terrestrial record of past climate change on timescales that range from centuries to millions of years. This research will benefit our understanding of the modern climate and the mechanisms which cause climate change. I have undertaken research in various geographic locations in order to develop well-dated records of the past extents of glaciers and ice sheets. Although my research generally involves glacial geologic studies, I have broader interests in Quaternary studies and geomorphology.
Detailed field research and geomorphic mapping form the basis of my projects. I also apply the surface-exposure dating method which is based on measurements of in-situ produced cosmogenic nuclides (e.g., Beryllium-10). See below for more information on the Dartmouth Cosmogenic Nuclide Laboratory. I also use lake and bog sediment records for reconstructing past environmental and climate conditions. See below for more information on the Dartmouth Sediment Core Processing Laboratory.
At present, I have ongoing research projects in three general geographic locations: Greenland, Peru and North America. Please see below for more detailed descriptions of these projects and associated publications. Contact me if you would like more information about any of my research.
I have been working on a collaborative project in the Scoresby Sund region of central East Greenland since 2004 (see photos above). The major question that this research addresses is whether enhanced seasonality (extremely cold winters and only moderately cold summers) characterized abrupt climate events of the last glacial period (e.g., Denton et al., 2005, Quaternary Science Reviews). Our results thus far support this "seasonality" hypothesis and are discussed in detail in two papers (Kelly et al., 2008; Hall et al., 2008). Other recent publications on Greenland include Kelly and Lowell, 2009 and Kelly and Long, 2009.
Ongoing work in this region is examining the timing of deglaciation from the Last Glacial Maximum ice extent as well as Holocene-age fluctuations of Greenland Ice Sheet outlets and local glaciers. See a recent article in the Dartmouth News about my East Greenland research.
Funding for my Greenland research is from NSF (ARC-0909270), (ANT-0527946) and the Comer Science and Education Foundation.
I am also working in western Greenland in association with the Dartmouth IGERT Polar Environmental Change program. See a recent article in the Dartmouth News about the IGERT graduate students.
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In an effort to further our understanding of the role of the tropics in the global climate system, I am developing a record of the past extents of Quelccaya Ice Cap and glaciers in the Cordillera Vilcanota in southeastern Peru (see photos above from field work in 2006 and 2008). Ice cores from Quelccaya provide detailed paleoclimate data for the last ~1,500 yrs (e.g., Thompson et al., 2006, PNAS). Surface-exposure and radiocarbon ages of moraines provide a record of ice cap and glacier extents since ~16,000 yrs ago. Results thus far were presented at the AGU Fall Meeting 2008 (Kelly et al., 2008 - AGU abstract).
In addition to developing paleoclimate data near Quelccaya, I am developing a low-latitude, high-altitude location to calibrate cosmogenic nuclide production rates and scaling factors using radiocarbon as an independent dating method. This project is in collaboration with the NSF-funded initiative CRONUS-Earth.
Funding for my Peru research is from NSF (EAR-1003460), CRONUS-Earth, the Lamont Climate Center, the Comer Science and Education Foundation and Dartmouth College.
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I am involved in three projects examining the Laurentide Ice Sheet during the Last Glacial Maximum and subsequent deglaciation.
For one collaborative project, I am applying surface-exposure dating of glacial features west of Lake Superior to test the hypothesis that the eastward drainage of Glacial Lake Agassiz caused the Younger Dryas. Tom Lowell (Univ. Cincinnati) and Tim Fisher (Univ. Toledo) have conducted extensive mapping and radiocarbon dating to track the Laurentide Ice Sheet retreat pattern in this area (Lowell et al., in press,QSR). Surface-exposure ages will be used to test the existing radiocarbon chronology.
For another project with Tom Lowell, I am providing a chronology of features associated with former ice streaming flow in the southwestern sector of the Laurentide Ice Sheet. This project will provide information about the style and rate at which the Laurentide collapsed during the last deglaciation.
In collaboration with Joerg Schaefer and his cosmogenic nuclide group at Lamont-Doherty Earth Observatory, I am working to define the timing of the Laurentide Ice Sheet maximum extent in New York, on Long Island, and its subsequent retreat up the Hudson Valley.
I am also beginning research using lake and bog sediment cores to examine the late-glacial and Holocene environmental and climate conditions in New England.
Funding for the North American research is from the Comer Science and Education Foundation and Dartmouth College.
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Located in Steele 213
The Dartmouth Cosmogenic Nuclide Laboratory is a semi-clean, wet chemistry laboratory. At the moment, we are processing samples for the extraction of the cosmogenic nulcide Beryllium-10 from quartz.
Jennifer Howley is the Cosmogenic Nuclide Laboratory manager.
A few photos of the cosmogenic lab:
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Located in Fairchild 217
I use a Livingston Piston Corer and a Universal Percussion Corer to obtain cores from lakes and bogs. We have the ability to conduct the following sediment core processing in the laboratory: Core photography, radiocarbon sample processing, Loss on Ignition (LOI), Magnetic Susceptability (MS) and grain-size analysis.
A few photos of sediment coring and core processing (from my EARS 15 Winter 2010 class, photo credits: J. Mehling):
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