Featured Research

from universities, journals, and other organizations

Geologists map prehistoric climate changes in Canada's Yukon Territory

Date:
May 8, 2012
Source:
University of Pittsburgh
Summary:
Scientists have analyzed sedimentary and geochemical records of water-level changes in Rantin Lake, located in the boreal forest of Canada's southeastern Yukon Territory.

Researchers at the University of Pittsburgh have joined an international group of scientists to study past climate changes in the Arctic. Comprising geologists from Pitt's Department of Geology and Planetary Science, the team has analyzed sedimentary and geochemical records of water-level changes in Rantin Lake, located in the boreal forest of Canada's southeastern Yukon Territory. The results were published online in the April issue of Journal of Paleolimnology as one of 18 articles dedicated to reconstructing Arctic lake sediments climate and environmental changes during the Holocene (about 12,000 years before present day).

"During the last 10,000 years, there have been certain times in which rapid climate change events occurred," said David Pompeani, lead author and a Pitt PhD geology student. "By analyzing Rantin Lake, we've contributed a piece of the puzzle toward mapping the timing and magnitude of these prehistoric events throughout the Arctic."

Rantin Lake is part of a watershed containing a series of small lakes hydrologically connected through groundwater flow. The regional climate is subarctic and characterized by warm, wet summers and dry, cold winters. The lake is located at 60 degrees north in the Canadian Arctic, only 30 degrees away from the North Pole, where climate change is expected to be amplified.

In July 2006, the Pitt team -- including Mark Abbott, associate professor of geology and planetary science, and Byron Steinman, a former PhD geology student (now a postdoctoral researcher at Penn State University) -- collected two sediment cores from the lake for analysis. The sediment cores were split and analyzed for paleoclimate proxy indicators, including geochemical composition, sedimentary structure, and macrofossil content (that which is visible without a microscope). The amount of water in a lake is directly related to its depth. Therefore, a loss in water during droughts is recorded by drop in lake levels, whereas wet periods are characterized by deep waters.

Using these proxy indicators, the researchers were able to make inferences about past variations in the balance between precipitation and evaporation in the southern Yukon. A comparison of the lake-level proxies with a previously developed fossil pollen record from the same lake found that rapid vegetation changes over the Holocene also occurred during shifts in the precipitation/evaporation balance, suggesting hydrologic conditions played an integral role in the evolution of the Yukon's ecosystem. The development of unique shallow-water sediment at the deep-water core site indicated that lake levels dropped significantly during a "megadrought" in the early Holocene.

"About 8,400 years ago, the lake almost dried out," said Pompeani. "We documented the timing of this drought and studied its transition to conditions more typical of what we observed in the late Holocene."

Pitt's study, says Pompeani, contributes to the long-term perspective on natural climate variability that is needed to understand historically unprecedented changes now occurring in the Arctic. Rapid changes in the Arctic climate system that occurred in the relatively recent past can be compared with climate models to improve the understanding of the processes responsible for such nonlinear changes.

Funding for this project was provided by the National Science Foundation.

The Holocene climate project focuses on climate records from the last 8,000 years, including two focus regions: eastern Beringia and the northwest Atlantic.


Story Source:

The above story is based on materials provided by University of Pittsburgh. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. P. Pompeani, B. A. Steinman, M. B. Abbott. A sedimentary and geochemical record of water-level changes from Rantin Lake, Yukon, Canada. Journal of Paleolimnology, 2012; DOI: 10.1007/s10933-012-9602-9

Cite This Page:

University of Pittsburgh. "Geologists map prehistoric climate changes in Canada's Yukon Territory." ScienceDaily. ScienceDaily, 8 May 2012. <www.sciencedaily.com/releases/2012/05/120508124549.htm>.
University of Pittsburgh. (2012, May 8). Geologists map prehistoric climate changes in Canada's Yukon Territory. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2012/05/120508124549.htm
University of Pittsburgh. "Geologists map prehistoric climate changes in Canada's Yukon Territory." ScienceDaily. www.sciencedaily.com/releases/2012/05/120508124549.htm (accessed October 21, 2014).

Share This



More Earth & Climate News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

Newsy (Oct. 20, 2014) The United Nations says water is a human right, but should it be free? Detroit has cut off water to residents who can't pay, and the U.N. isn't happy. Video provided by Newsy
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
White Rhino's Death In Kenya Means Just 6 Are Left

White Rhino's Death In Kenya Means Just 6 Are Left

Newsy (Oct. 20, 2014) Suni, a rare northern white rhino at Ol Pejeta Conservancy, died Friday. This, as many media have pointed out, leaves people fearing extinction. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins