| Title | Continental stretching preceding the opening of the Drake Passage; evidence from Tierra del Fuego |
| Author | Ghiglione, M.C.; Yagupsky, D.; Ghidella, M.; Ramos, V.A. |
| Author Affil | Ghiglione, M.C., Universidad de Buenos Aires, Laboratorio de Tectónica Andina, Buenos Aires, Argentina. Other: Instituto Antártico Argentino, Argentina |
| Source | Geology (Boulder), 36(8), p.643-646, . Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091- 7613 |
| Publication Date | Aug. 2008 |
| Notes | In English. With GSA Data Repository Item 2008154. 23 refs. GeoRef Acc. No: 285291 |
| Index Terms | Argentina; Drake Passage; Scotia Sea; Andes--Southern Andes; Southern Ocean; South America--Tierra del Fuego Island; Andes; Antarctic Circumpolar Current; Antarctic Plate; carbonate rocks; Cenozoic; continental crust; cooling; crust; Eocene; extension; extension faults; faults; field studies; geophysical methods; geophysical profiles; geophysical surveys; lower Eocene; magnetic methods; Paleocene; paleoclimatology; Paleogene; paleogeography; plate tectonics; Rio Bueno Formation; sedimentary rocks; seismic methods; seismic profiles; Sloggett Basin; South America; South American Plate; Southern Andes; surveys; Tertiary; Tierra del Fuego; Tierra del Fuego Island; unconformities; upper Paleocene |
| Abstract | Age estimates for the onset of a seaway through the Drake Passage range from middle Eocene to early Miocene, complicating interpretations of the relation between ocean circulation and Cenozoic global cooling. Here we present evidence for the presence of a latest Paleocene-early Eocene extensional basin (i.e., lateral rift) in Tierra del Fuego. An accurately dated postrift unconformity indicates that extensional faulting ended in the studied area ca. 49 Ma, in concurrence with a previously reported eightfold increase in South America- Antarctica separation rate, and the proposed onset of oceanic basins in the incipient Drake Passage. The coincidence of these facts indicates progressive strain concentration on the zone of future crustal separation (i.e., Drake Passage) after abandonment of lateral rifts ca. 49 Ma. Although the described extensional depocenters did not allow the exchange of water between the Pacific and Atlantic Oceans, they represent a direct indication of continental lithospheric stretching preceding the recently proposed Eocene opening of embryonic basins in the West Scotia Sea. |
| URL | http://hdl.handle.net/10.1130/G24857A.1 |
| Publication Type | journal article |
| Record ID | 84291 |