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Constraints on the age of the Great Sand Dunes, Colorado, from subsurface stratigraphy and OSL dates

Quaternary Research

By:
, , , and
DOI: 10.1016/j.yqres.2013.09.009

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Abstract

The age of the Great Sand Dunes has been debated for nearly 150 yr. Seven ages ranging from Miocene to late Holocene have been proposed for them. This paper presents new information—chiefly subsurface stratigraphic data, OSL dates, and geomorphic evidence—that indicates that the Great Sand Dunes began to form in the latter part of the middle Pleistocene. The dunes overlie a thick wedge of piedmont-slope deposits, which in turn overlies sediment of Lake Alamosa, a paleolake that began to drain about 440 ka. The wedge of piedmont-slope deposits extends westward for at least 23 km and is as much as 60 m thick at a distance of 10 km from the Sangre de Cristo Range. Ostracodes from one well indicate that the eastern shoreline of Lake Alamosa extended to within 4.3 km of where the Great Sand Dunes eventually formed. The time represented by the wedge of piedmont-slope deposits is not known exactly, but the wedge post-dates 440 ka and was in place prior to 130 ka because by then the dunes overlying it were sufficiently close and tall enough to obstruct streams draining from the Sangre de Cristo Range.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Constraints on the age of the Great Sand Dunes, Colorado, from subsurface stratigraphy and OSL dates
Series title:
Quaternary Research
DOI:
10.1016/j.yqres.2013.09.009
Volume
80
Issue:
3
Year Published:
2013
Language:
English
Publisher:
American Quaternary Association
Publisher location:
New York, NY
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Quaternary Research
First page:
435
Last page:
446