Arctic Field Projects



Project Title: Arctic mountain glacier response to past global changes - a pilot study from the Brooks Range, Alaska (Award# 0902797)

PI: Briner, Jason P (jbriner@buffalo.edu)
Phone: (716) 645.4326 
Institute/Department: U at Buffalo, Department of Geology 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. William Wiseman (wwiseman@nsf.gov)
Discipline(s): | Geological Sciences\Tehprastratigraphy | Geological Sciences\Tephrochronology | Meteorology and Climate\Modeling | Meteorology and Climate\Paleoclimatology |

Project Web Site(s):
NSF_Award_Info: http://www.nsf.gov/awardsearch/showAward.do?AwardN...

Science Summary:
This pilot project addresses reconstruction of the timing and extent of mountain glacier fluctuations in the Brooks Range of Alaska through the Holocene, including the Holocene thermal maximum. Specifically, this project will collect data to test the hypothesis that factors other than summer insolation are required to explain major centennial-scale changes in the extent of mountain glaciers in the North American Arctic. Previous glacial-geologic studies in the Brooks Range, which relied on lichenometry, concluded that glaciers reached their inter-glacial maximum during the mid-Holocene, about 5 ka. This result is unexpected because the decrease in summer insolation due to orbital forcing during the second half of the Holocene was most pronounced at high latitude. If summer insolation were the primary control on ice extent, then glaciers in the Brooks Range would have reached their maximum extent late during the Little Ice Age (19th century), as they did in the southern part of Alaska. The PI suspects that the seasonal duration of sea-ice cover over the adjacent Arctic Ocean influences the availability of moisture to generate snow during transitional seasons. This study builds on the PI’s recent success at generating records of Holocene glacier activity using proglacial lake sediments and cosmogenic 10Be dating of Holocene moraine boulders elsewhere in Alaska. It combines 10Be dating of middle and late Holocene moraines with lake coring to generate a well-dated record of glacier variability through the Holocene. The geochronology of lacustrine sediments will be based on a suite of radioisotopes, and the PI will search for cryptotephras as part of a circum-arctic search for Holocene marker beds.

Logistics Summary:
This project’s researchers will travel to the Kurupa Valley, in the western Brooks Range of Alaska, for reconnaissance to determine if the area has lakes and moraines suitable for paleoclimate studies. In the summer of 2010, a team of four will travel to Bettles from Fairbanks. There, they will put in to the research site via float plane and establish two tent camps at the lakes. They will use an inflatable boat with a motor to map the lake bottom and collect sediment cores from Upper Kurupa and Kurupa lakes; these studies will help the team determine the nature of the sediments, and to assess whether there are suitable materials for radiocarbon dating. In addition, the team will visit the valley headwaters where several extant glaciers have frontal moraines previously mapped as spanning the last ~5000 years; they will collect rock samples with which to assess the suitability of the moraines for 10Be exposure dating. The team will spend two weeks in the field before taking out via float plane and returning to Bettles.

CPS will provide a portion of the air support FAI><Bettles, float-plane charters, an inflatable boat/motor, and camp and communications/safety gear. The researchers will arrange all other logistics (including the cost of flying two team members to Bettles from Fairbanks) and pay for them through the grant.
SeasonField SiteDate InDate Out#People
2010Alaska - Kurupa Lake06 / 30 / 2010 07 / 13 / 20104
2010Alaska - Upper Kurupa Lake06 / 30 / 2010 07 / 13 / 20104
 


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