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Plio-Pleistocene climatic transition and the lifting of the Teton Range, Wyoming

Quaternary Research

By:
, , , and
DOI: 10.1016/j.yqres.2006.10.006

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Abstract

Fine-grained lacustrine, riverine and ash-fall sediments of the Shooting Iron Formation, whose late Pliocene age is established by Blancan gastropods and vertebrates, yield a pollen flora that is essentially similar in composition to the modern pollen rain in the Jackson Hole area. The Pliocene assemblage suggests a climate like that of the Jackson valley and foothills today. These spectra also resemble a Pliocene pollen flora from Yellowstone Park dated at ??? 2.02??Ma. However, the underlying Miocene Teewinot sediments differ by containing pollen of four exotic deciduous hardwoods (Tertiary relicts) that suggest a summer-moist climate, unlike that of today. The Shooting Iron sediments lie with an angular unconformity on and above the Miocene lake sediments of the Teewinot Formation. Both of these deposits probably preceded the main uplift of the Teton Range based on the absence of Precambrian clasts in the Tertiary valley deposits. Because the Pliocene floras were modern in aspect, a Plio-Pleistocene transition would be floristically imperceptible here. The sequence denotes a protracted period of relative stability of climate during Teewinot time, and a shift in vegetational state (summer-wet trees drop out) sometime between the latest Miocene and latest Pliocene. The Pliocene spectra suggest a dry, cooler climate toward the end of Shooting Iron time. ?? 2006 University of Washington.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Plio-Pleistocene climatic transition and the lifting of the Teton Range, Wyoming
Series title:
Quaternary Research
DOI:
10.1016/j.yqres.2006.10.006
Volume
67
Issue:
1
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Quaternary Research
First page:
1
Last page:
11