Tectonic significance of paleobotanically estimated climate and altitude of the late Eocene erosion surface, Colorado

Research Article| July 01, 1992 Tectonic significance of paleobotanically estimated climate and altitude of the late Eocene erosion surface, Colorado Kathryn M. Gregory; Kathryn M. Gregory 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Search for other works by this author on: GSW Google Scholar Clement G. Chase Clement G. Chase 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Search for other works by this author on: GSW Google Scholar Author and Article Information Kathryn M. Gregory 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Clement G. Chase 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (7): 581–585. https://doi.org/10.1130/0091-7613(1992)020<0581:TSOPEC>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Kathryn M. Gregory, Clement G. Chase; Tectonic significance of paleobotanically estimated climate and altitude of the late Eocene erosion surface, Colorado. Geology 1992;; 20 (7): 581–585. doi: https://doi.org/10.1130/0091-7613(1992)020<0581:TSOPEC>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Erosion beveled the Laramide Front Range uplift in Colorado to a surface of low relief by the end of the Eocene. This study uses J. A. Wolfe's new multivariate climate analysis techniques to determine the paleoelevation of this regional surface by examining the overlying 35 Ma Florissant flora. A multiple regression model explaining 93.3% of the variance in mean annual temperature was developed using Wolfe's dataset of 31 leaf physiognomic character states for 86 modern vegetation sites. These character states were scored on 29 species collected from one facies of the Florissant Lake Beds. The paleotemperature estimate of mean annual temperature (10.7 ±1.5 °C) derived from these data, when combined with sea-level temperature and terrestrial lapse rate, implies a late Eocene paleoelevation of 2.4-2.7 km. Pliocene uplift is thus not required to explain the present elevation of 2.5 km. It is unclear when and why the southern Rocky Mountains achieved this elevation. Magmatic crustal thickening can explain the late Eocene high elevation of the southern Rockies, but neither this mechanism nor compressive thickening explains why the Great Plains, which are tied to the Florissant elevation by the Wall Mountain Tuff, were also high. This paleoelevation estimate indicates that regional surfaces of planation could be formed at high elevation in the Eocene, probably because of peculiarities of the Eocene climate. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.