Late glacial aridity in southern Rocky Mountains

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:198211

Davis, O K; Pitblado, B L ^[1]

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1. Univ. of Arizona, Tucson, AZ (United States)

While the slopes of the present-day Colorado Rocky Mountains are characterized by large stands of subalpine and montane conifers, the Rockies of the late glacial looked dramatically different. Specifically, pollen records suggest that during the late glacial, Artemisia and Gramineae predominated throughout the mountains of Colorado. At some point between 11,000 and 10,000 B.P., however, both Artemisia and grasses underwent a dramatic decline, which can be identified in virtually every pollen diagram produced for Colorado mountain sites, including Como Lake (Sangre de Cristo Mountains), Copley Lake and Splains; Gulch (near Crested Butte), Molas Lake (San Juan Mountains), and Redrock Lake (Boulder County). Moreover, the same pattern seems to hold for pollen spectra derived for areas adjacent to Colorado, including at sites in the Chuska Mountains of New Mexico and in eastern Wyoming. The implications of this consistent finding are compelling. The closest modem analogues to the Artemisia- and Gramineae-dominated late-glacial Colorado Rockies are found in the relatively arid northern Great Basin, which suggests that annual precipitation was much lower in the late-glacial southern Rocky Mountains than it was throughout the Holocene.

• Research Organization: Rust Geotech, Inc., Grand Junction, CO (United States)
• OSTI ID: 198211
• Report Number(s): CONF-9409325--; ON: DE96003275
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ANNUAL VARIATIONS
ATMOSPHERIC PRECIPITATIONS
COLORADO
PALEOCLIMATOLOGY
PLANTS
POPULATION DYNAMICS
QUATERNARY PERIOD
ROCKY MOUNTAINS