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New age constraints for early Paleogene strata of central Patagonia, Argentina: Implications for the timing of South American Land Mammal Ages

2017; Geological Society of America; Volume: 129; Issue: 7-8 Linguagem: Inglês

10.1130/b31561.1

1943-2674

J. Marcelo Krause, William C. Clyde, Mauricio Ibáñez-Mejía, Mark D. Schmitz, Timothy Barnum, Eduardo S. Bellosi, Peter Wilf,

Geology and Paleoclimatology Research

Research Article| July 01, 2017 New age constraints for early Paleogene strata of central Patagonia, Argentina: Implications for the timing of South American Land Mammal Ages J. Marcelo Krause; J. Marcelo Krause † 1CONICET–Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100, Trelew, Argentina2Departamento de Geología, Universidad Nacional de la Patagonia San Juan Bosco, Ruta Provincial 1 s/n, 9000, Comodoro Rivadavia, Chubut, Argentina †mkrause@mef.org.ar Search for other works by this author on: GSW Google Scholar William C. Clyde; William C. Clyde 3Department of Earth Sciences, University of New Hampshire, 56 College Road, Durham, New Hampshire 03824, USA Search for other works by this author on: GSW Google Scholar Mauricio Ibañez-Mejía; Mauricio Ibañez-Mejía 4Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA5Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York 14627, USA Search for other works by this author on: GSW Google Scholar Mark D. Schmitz; Mark D. Schmitz 6Department of Geosciences, Boise State University, 1910 University Drive, Boise, Idaho 83725, USA Search for other works by this author on: GSW Google Scholar Timothy Barnum; Timothy Barnum 3Department of Earth Sciences, University of New Hampshire, 56 College Road, Durham, New Hampshire 03824, USA Search for other works by this author on: GSW Google Scholar Eduardo S. Bellosi; Eduardo S. Bellosi 7CONICET–Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, 1405 Buenos Aires, Argentina Search for other works by this author on: GSW Google Scholar Peter Wilf Peter Wilf 8Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA Search for other works by this author on: GSW Google Scholar Author and Article Information J. Marcelo Krause † 1CONICET–Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100, Trelew, Argentina2Departamento de Geología, Universidad Nacional de la Patagonia San Juan Bosco, Ruta Provincial 1 s/n, 9000, Comodoro Rivadavia, Chubut, Argentina William C. Clyde 3Department of Earth Sciences, University of New Hampshire, 56 College Road, Durham, New Hampshire 03824, USA Mauricio Ibañez-Mejía 4Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA5Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York 14627, USA Mark D. Schmitz 6Department of Geosciences, Boise State University, 1910 University Drive, Boise, Idaho 83725, USA Timothy Barnum 3Department of Earth Sciences, University of New Hampshire, 56 College Road, Durham, New Hampshire 03824, USA Eduardo S. Bellosi 7CONICET–Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, 1405 Buenos Aires, Argentina Peter Wilf 8Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA †mkrause@mef.org.ar Publisher: Geological Society of America Received: 27 Apr 2016 Revision Received: 28 Sep 2016 Accepted: 10 Jan 2017 First Online: 06 Jul 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2017 Geological Society of America GSA Bulletin (2017) 129 (7-8): 886–903. https://doi.org/10.1130/B31561.1 Article history Received: 27 Apr 2016 Revision Received: 28 Sep 2016 Accepted: 10 Jan 2017 First Online: 06 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. Marcelo Krause, William C. Clyde, Mauricio Ibañez-Mejía, Mark D. Schmitz, Timothy Barnum, Eduardo S. Bellosi, Peter Wilf; New age constraints for early Paleogene strata of central Patagonia, Argentina: Implications for the timing of South American Land Mammal Ages. GSA Bulletin 2017;; 129 (7-8): 886–903. doi: https://doi.org/10.1130/B31561.1 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 SocietyGSA Bulletin Search Advanced Search Abstract The Río Chico Group in the San Jorge Basin of central Patagonia (Argentina) preserves some of South America's most significant Paleogene records of biotic and climatic change. Three of its constituent formations, the Peñas Coloradas, Las Flores, and Koluel-Kaike, host vertebrate faunas referred to the "Carodnia faunal zone," the Itaboraian South American Land Mammal Age (SALMA), and the Riochican SALMA. However, the precise absolute ages of these units, and thus their associated faunas and paleoclimate records, are poorly resolved. Herein, we report new paleomagnetic and geochronologic results from these formations in south-central Chubut Province, Argentina. U-Pb dating of four volcanic ashes, using both laser ablation–multicollector–inductively coupled plasma–mass spectrometry and high-resolution chemical abrasion–isotope dilution–thermal ionization mass spectrometry, indicates ages of igneous crystallization of 51.403 ± 0.037 (0.045) [0.071]Ma for a level within the middle Las Flores Formation and 46.714 ± 0.012 (0.026) [0.057]Ma, 44.579 ± 0.013 (0.026) [0.054]Ma, and 42.856 ± 0.017 (0.027) [0.054]Ma for levels in the lower, middle, and upper Koluel-Kaike Formation, respectively. Combining these with previous isotopic ages in our new magnetostratigraphic framework, we correlate the Peñas Coloradas Formation to chrons C27n-26r (ca. 62.5 to ca. 61.6 Ma; late Danian) and the section from the middle Las Flores to the uppermost Koluel-Kaike to chrons C23n to C19r (ca. 51.4–42.2 Ma; mid Ypresian–late Lutetian). We combine these data with other recently published chronostratigraphic results from Paleogene units in Patagonia to better constrain the ages of noteworthy Paleogene plant and mammal fossil sites in Patagonia and to develop a revised temporal calibration of the Las Flores, Vacan, and "Sapoan" faunas. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.