Late-glacial and Holocene fluctuations at Monte Fitz Roy (49°S), Southern Patagonia

KAPLAN, MICHAEL; SCHAEFER, JOERG; SAGREDO, ESTEBAN; MATEO MARTINI; REYNHOUT, SCOTT; ARAENA, JUAN CARLOS

San Francisco

Congreso; American Geophysical Union Fall Meeting 2016; 2016

AGU

Formerglacier fluctuations provide a crucial terrestrial record of paleoclimate inalpine regions. However, uneven coverage of paleoglacier chronologies hashindered efforts to decipher the nature of regional and interhemispheric climaterelationships, without which mechanisms driving past climate variability cannotbe adequately evaluated. We present a preliminary chronology of fluctuations ofthe Torre glacier (49.3°S), adjacent to the Southern Patagonian Ice Field, asdetermined using geomorphic mapping and Be cosmogenic surface exposure datingof former glacier limits. The record spans the last glacial-interglacialtransition to the latest Holocene, and no fewer than seven progressivelyless-extensive glacier advances are observed during this time period. Thelate-glacial record parallels the Antarctic pattern of deglacial temperaturefluctuations, with glacier maxima at c. 18 and 13 ka corresponding to the onsetof the termination and the Antarctic Cold Reversal, respectively. The Holocenerecord?s relationship to the Antarcticis less clear; the stepwise pattern of declining glacier extent most closelyparallels that of New Zealand. Taken together, fluctuations of the Torreglacier indicate changing modes of control on regional glaciation, dependent uponthe glacial versus interglacial state of global climate.