Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure

Abstract

Research Article| May 01, 2012 Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure Camilo Montes; Camilo Montes † 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá2Geociencias, Universidad de los Andes, Calle 1A # 18A-10, Edificio IP, Bogotá DC, Colombia †E-mail: cmontes@uniandes.edu.co Search for other works by this author on: GSW Google Scholar A. Cardona; A. Cardona 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá3Ingenieria de Petroleos, Universidad Nacional de Colombia, Carrera 80 No. 65-223, Medellín, Colombia Search for other works by this author on: GSW Google Scholar R. McFadden; R. McFadden 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar S.E. Morón; S.E. Morón 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar C.A. Silva; C.A. Silva 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar S. Restrepo-Moreno; S. Restrepo-Moreno 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá4Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, 24 Florida 32611, USA Search for other works by this author on: GSW Google Scholar D.A. Ramírez; D.A. Ramírez 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar N. Hoyos; N. Hoyos 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar J. Wilson; J. Wilson 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar D. Farris; D. Farris 5Department of Earth, Ocean and Atmospheric Science, Florida State University, 1017 26 Academic Way, Tallahassee, Florida 32306-4520, USA Search for other works by this author on: GSW Google Scholar G.A. Bayona; G.A. Bayona 6Corporación Geológica Ares, Calle 44A # 53-96, Bogotá, Colombia Search for other works by this author on: GSW Google Scholar C.A. Jaramillo; C.A. Jaramillo 1Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Republic of Panamá Search for other works by this author on: GSW Google Scholar V. Valencia; V. Valencia 7Department of Geosciences, University of Arizona, Gould-Simpson Building #77, 1040 E Street, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar J. Bryan; J. Bryan 8Geology/Oceanography, Northwest Florida State College, 100 College Boulevard, Niceville, Florida 32578, USA Search for other works by this author on: GSW Google Scholar J.A. Flores J.A. Flores 9Facultad de Ciencias, Departamento de Geología, Universidad de Salamanca, 37008 Salamanca, Spain Search for other works by this author on: GSW Google Scholar GSA Bulletin (2012) 124 (5-6): 780–799. https://doi.org/10.1130/B30528.1 Article history received: 07 Apr 2011 rev-recd: 01 Oct 2011 accepted: 19 Oct 2011 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Camilo Montes, A. Cardona, R. McFadden, S.E. Morón, C.A. Silva, S. Restrepo-Moreno, D.A. Ramírez, N. Hoyos, J. Wilson, D. Farris, G.A. Bayona, C.A. Jaramillo, V. Valencia, J. Bryan, J.A. Flores; Evidence for middle Eocene and younger land emergence in central Panama: Implications for Isthmus closure. GSA Bulletin 2012;; 124 (5-6): 780–799. doi: https://doi.org/10.1130/B30528.1 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 rise of the Isthmus of Panama, linked to a number of climatic, paleoceanographic, and biological events, has been studied mostly from indirect, often distal, geochemical and biotic evidence. We have upgraded existing geologic mapping in central Panama with more than 2000 field stations, over 40 petrographic analyses, and more than 30 new geochronological and thermochronological analyses. This data set suggests that the isthmus was an uninterrupted chain above sea level from late Eocene until at least late Miocene times. The basement complex of central Panama is a folded-faulted, ∼3-km-thick arc sequence, intruded by granitoid bodies and onlapped by mildly deformed upper Eocene and Oligocene strata. Six U/Pb zircon ages in the granitoids—along with published geochronological data—reveal intense late Paleocene to middle Eocene magmatism (58–39 Ma), a temporary cessation of magmatic activity between 38 and 27 Ma, and renewed magmatism between 25 and 15 Ma in a position ∼75 km south of the former magmatic axis. Thermochronological analyses in zircon (eight U-Th/He ages), and in apatite crystals (four U-Th/He ages and nine fission-track ages) obtained from a subset of 58–54 Ma granitoid bodies record a concordant Lutetian-age (47–42 Ma) cooling from ∼200 °C to ∼70 °C in ∼5 m.y., and cooling below ∼40 °C between 12 and 9 Ma. Cooling is linked to exhumation by an angular unconformity that separates the deformed basement complex below from mildly deformed, upper Eocene to Oligocene terrestrial to shallow-marine strata above. Exhumation and erosion of the basement complex are independently confirmed by lower Miocene strata that have a detrital zircon signature that closely follows the central Panama basement complex age distribution. These results greatly restrict the width and depth of the strait separating southern Central America from South America, and challenge the widely accepted notion that the Central American Seaway closed in late Pliocene time, when the ice age began. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.