Hostname: page-component-76fb5796d-vfjqv Total loading time: 0 Render date: 2024-04-26T03:54:05.223Z Has data issue: false hasContentIssue false

Pleistocene Glaciation in the Southern Lake District of Chile

Published online by Cambridge University Press:  20 January 2017

Stephen C. Porter*
Affiliation:
Quaternary Research Center, University of Washington, Seattle, Washington 98195

Abstract

Relative-age criteria permit deposits of successive Andean glacier advances in the southern Lake District of Chile to be divided into four mappable drift sheets, the oldest two of which overlie Tertiary bedrock along the eastern flank of the Cordillera de la Costa. Only the youngest drift (Llanquihue) is datable by radiocarbon. During the most extensive ice advance of the last glaciation the Lago Llanquihue glacier was about 95 km long and reached an estimated maximum thickness of between 1000 and 1300 m. Glacier equilibrium lines at that time lay about 1000 m below their present level and rose eastward with a gradient of about 5 m/km. Successive ice advances in the Lago Llanquihue basin, which resulted in construction of end moraines and associated outwash plains beyond the lake margin, culminated sometime before about 20,000 yr ago and between 20,000 and 19,000 yr ago. A later readvance, inferred from the sedimentary record of lake-level fluctuations in the basin, had begun by about 15,000 yr ago and culminated shortly after 13,000 yr ago. A comparable, but less-closely dated, record of ice advances is found northwest of Seno Reloncaví and on Isla Chiloé. Deglaciation following the latest advance is likely to have been rapid, for the major glacier lobes fronted on deep water bodies that would have promoted extensive calving.

Type
Original Articles
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bruggen, J. 1950. Fundamentos de la geología de Chile Instituto Geográfico Militar Santiago.Google Scholar
Burke, R.M., Birkeland, P.W. 1979. Reevaluation of multiparameter relative dating techniques and their application to the glacial sequence along the eastern escarpment of the Sierra Nevada, California. Quaternary Research 11. 2151.CrossRefGoogle Scholar
Casertano, L. 1963. Catalogue of the active volcanoes and solfatara fields of the Chilean continent. In “International Volcanological Association Catalogue of the Active Volcanoes of the World.” Part XVGoogle Scholar
Colman, S.M. 1981. Rock-weathering rates as functions of time. Quaternary Research 15. 250264.CrossRefGoogle Scholar
Field, W.O. 1976. Observations of glacier variations in Glacier Bay National Monument. In “Proceedings of the First Conference on Scientific Research in the National Parks.” Linn, R.M. pp. 803808. U.S. Dept. Interior, Nat. Park Serv. Trans. and Proc. Ser. 5.Google Scholar
Flint, R.F., Fidalgo, F. 1964. Glacial geology of the east flank of the Argentine Andes between latitude 39°10′ S and latitude 41°20′ S. Geological Society of America, Bulletin 75. 335352.Google Scholar
Flint, R.F., Fidalgo, F. 1969. Glacial drift in the eastern Argentine Andes between latitude 41°10′ S and latitude 43°10′ S. Geological Society of America, Bulletin 80. 10431052.Google Scholar
Heusser, C.J. 1960. Late Pleistocene environments of the Laguna de San Rafael area, Chile. Geographical Review 50. 555577.Google Scholar
Heusser, C.J. 1966. Late Pleistocene pollen diagrams from the province of Llanquihue, southern Chile. American Philosophical Society, Proceedings 110. 269305.Google Scholar
Heusser, C.J. 1972a. On the occurrence of Lycopodium fuegianum during late Pleistocene interstades in the Province of Osorno, Chile. Torrey Botanical Club Bulletin 99. 178184.Google Scholar
Heusser, C.J. 1972b. An additional postglacial pollen diagram from Patagonia Occidental. Pollen et spores 14. 157167.Google Scholar
Heusser, C.J. 1974. Vegetation and climate of the southern Chilean Lake District during and since the last interglaciation. Quaternary Research 4. 290315.CrossRefGoogle Scholar
Heusser, C.J. 1976. Palynology and depositional environment of the Río Ignao nonglacial deposit, Province of Valdivia, Chile. Quaternary Research 6. 273279.Google Scholar
Heusser, C.J. 1981. Palynology of the last interglacial-glacial cycle in midlatitudes of southern Chile. Quaternary Research 16. 293321.CrossRefGoogle Scholar
Heusser, C.J., Flint, R.F. 1977. Quaternary glaciations and environments of northern Isla Chiloé, Chile. Geology 5. 305308.Google Scholar
Heusser, C.J., Streeter, S.S. 1980. A temperature and precipitation record of the past 16,000 years in southern Chile. Science 210. 13451347.Google Scholar
Instituto Hidrografico de Chile. 1968 Chart 707 (Puerto Montt a Isla Tac)1:50,000Google Scholar
Ives, P.C., Levin, B., Robinson, R.D., Rubin, M. 1964. U.S. Geological Survey radiocarbon dates VIII. Radiocarbon 6. 3776.Google Scholar
Kobayashi, H., Hirose, T., Sugino, M., Watanabe, N. 1974. University of Tokyo radiocarbon measurements V. Radiocarbon 16. 381387.CrossRefGoogle Scholar
Laugenie, C.A., Mercer, J.H. 1973. Southern Chile: A chronology of the last glaciation. In “IX INQUA Congress Abstracts Christchurch, N.Z.202203.Google Scholar
Lorius, C., Merlivat, L., Jouzel, J., Pourchet, M. 1979. A 30,000-yr isotope climatic record from Antarctic ice. Nature (London) 280. 644648.Google Scholar
Mercer, J.H. 1972. Chilean glacial chronology 20,000 to 11,000 Carbon-14 years ago: Some global comparisons. Science 176. 11181120.Google Scholar
Mercer, J.H. 1976. Glacial history of southernmost South America. Quaternary Research 6. 125166.Google Scholar
Porter, S.C. 1971. Fluctuations of late Pleistocene alpine glaciers in western North America. In “The Late Cenozoic Glacial Ages.”. Turekian, K.K. 307329. Yale Univ. Press New Haven, Conn.Google Scholar
Porter, S.C. 1975. Equilibrium-line altitudes of late Quaternary glaciers in the Southern Alps, New Zealand. Quaternary Research 5. 2747.Google Scholar
Porter, S.C. 1980. Rapid deglaciation of alpine regions at the end of the last glaciation. In “Abstracts and Program, Sixth Biennial Meeting, American Quaternary Association.”. 157 Google Scholar
Rabassa, J., Rubulis, S., Brandini, A. 1980. East-west and north-south snowline gradients in the northern Patagonian Andes, Argentina. In “World Glacier Inventory.” IAHS-AISH Publication 126. 110.Google Scholar
Robin, G.de Q. 1977. Ice cores and climatic change. Philosophical Transactions of the Royal Society of London, Series B 280. 143168.Google Scholar
Totten, S.M. 1969. Overridden recessional moraines of north-central Ohio. Geological Society of America, Bulletin 80. 19311946.Google Scholar