skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA

Abstract

Paleobotanical records from two high-altitude (>3,300 m) sites in Colorado show a clear and immediate response to the Younger Dryas climate oscillation. The Black Mountain Lake and Sky Pond records indicate that alpine timberline migrated upslope to near-modern elevations during the late Bolling-Allerod (13.6--12.9 ka). Subsequent declines in arboreal pollen percentages and accumulation rates during the Younger Dryas interval (12.9--11.7 ka) reflect a downslope displacement of the alpine timberline ecotone of 60--120 m in elevation. This change translates to a cooling of summer temperature by {approximately}0.4--0.9 C and is consistent with proposed Younger Dryas advances of alpine glaciers in the Rocky Mountains to positions close to Little Ice Age maxima. Alpine timberline readvanced upslope to elevations above both sites between 11.7 and 11.4 ka. The concomitant response of temperature-sensitive alpine timberline vegetation in Colorado and late-glacial changes in North Atlantic thermohaline circulating implicates a rapid, widespread atmospheric transmission of the Younger Dryas climate oscillation.

Authors:
;
Publication Date:
Research Org.:
Univ. of Colorado, Boulder, CO (US)
OSTI Identifier:
20014038
Resource Type:
Journal Article
Journal Name:
Geology
Additional Journal Information:
Journal Volume: 28; Journal Issue: 1; Other Information: PBD: Jan 2000; Journal ID: ISSN 0091-7613
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ROCKY MOUNTAINS; COLORADO; CLIMATIC CHANGE; GEOBOTANY; GEOLOGIC HISTORY; TREES; GLACIERS

Citation Formats

Reasoner, M A, and Jodry, M A. Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA. United States: N. p., 2000. Web. doi:10.1130/0091-7613(2000)028<0051:RROATV>2.3.CO;2.
Reasoner, M A, & Jodry, M A. Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA. United States. https://doi.org/10.1130/0091-7613(2000)028<0051:RROATV>2.3.CO;2
Reasoner, M A, and Jodry, M A. 2000. "Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA". United States. https://doi.org/10.1130/0091-7613(2000)028<0051:RROATV>2.3.CO;2.
@article{osti_20014038,
title = {Rapid response of alpine timberline vegetation to the Younger Dryas climate oscillation in the Colorado Rocky Mountains, USA},
author = {Reasoner, M A and Jodry, M A},
abstractNote = {Paleobotanical records from two high-altitude (>3,300 m) sites in Colorado show a clear and immediate response to the Younger Dryas climate oscillation. The Black Mountain Lake and Sky Pond records indicate that alpine timberline migrated upslope to near-modern elevations during the late Bolling-Allerod (13.6--12.9 ka). Subsequent declines in arboreal pollen percentages and accumulation rates during the Younger Dryas interval (12.9--11.7 ka) reflect a downslope displacement of the alpine timberline ecotone of 60--120 m in elevation. This change translates to a cooling of summer temperature by {approximately}0.4--0.9 C and is consistent with proposed Younger Dryas advances of alpine glaciers in the Rocky Mountains to positions close to Little Ice Age maxima. Alpine timberline readvanced upslope to elevations above both sites between 11.7 and 11.4 ka. The concomitant response of temperature-sensitive alpine timberline vegetation in Colorado and late-glacial changes in North Atlantic thermohaline circulating implicates a rapid, widespread atmospheric transmission of the Younger Dryas climate oscillation.},
doi = {10.1130/0091-7613(2000)028<0051:RROATV>2.3.CO;2},
url = {https://www.osti.gov/biblio/20014038}, journal = {Geology},
issn = {0091-7613},
number = 1,
volume = 28,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 2000},
month = {Sat Jan 01 00:00:00 EST 2000}
}