The Timing and Magnitude of Mountain Glaciation in the Tropical Andes
JOURNAL OF QUATERNARY SCIENCE (2008) 23(6-7) 609–634 Copyright ß 2008 John Wiley & Sons, Ltd. Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/jqs.1224 The timing and magnitude of mountain glaciation in the tropical Andes JACQUELINE A. SMITH,1* BRYAN G. MARK2 and DONALD T. RODBELL3 1 Department of Physical and Biological Sciences, The College of Saint Rose, Albany, New York, USA 2 Department of Geography, The Ohio State University, Columbus, Ohio, USA 3 Geology Department, Union College, F. W. Olin Center, Schenectady, New York, USA Smith, J. A., Mark, B. G. and Rodbell, D. T. 2008. The timing and magnitude of mountain glaciation in the tropical Andes. J. Quaternary Sci., Vol. 23 pp. 609–634. ISSN 0267-8179. Received 18 June 2007; Revised 26 February 2008; Accepted 27 May 2008 ABSTRACT: The Andes of Ecuador, Peru and Bolivia host the majority of the world’s tropical glaciers. In the tropical Andes, glaciers accumulate during the wet season (austral summer) and ablate year- round. Precipitation is delivered mainly by easterlies, and decreases both N–S and E–W. Chronological control for the timing of glacial advances in the tropical Andes varies. In Ecuador, six to seven advances have been identified; dating is based on radiocarbon ages. Timing of the local Last Glacial Maximum (LGM) and the existence of Younger Dryas advances remain controversial. In Peru, local variability in glaciation patterns is apparent. Surface exposure dating in the Cordillera Blanca and Junin Plain suggests that the local LGM may have been early (30 ka), although uncertainties in age calculations remain; the local LGM was followed by a Lateglacial readvance/stillstand and preceded by larger glaciations.
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