Chronologies of the Last Glacial Maximum and its Termination in the Andes (∼10–55°S) Based on Surface Exposure Dating

2009 ◽  
pp. 61-87 ◽  
Author(s):  
Roland Zech ◽  
Jacqueline Smith ◽  
Michael R. Kaplan
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Surface Exposure Dating ◽  
Last Glacial ◽  
Exposure Dating ◽  
The Andes ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Glacier Modeling and the Climate of Patagonia during the Last Glacial Maximum

1994 ◽  
Vol 42 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Nick Hulton ◽  
David Sugden ◽  
Antony Payne ◽  
Chalmers Clapperton
Keyword(s):  
Mass Balance ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Equilibrium Line Altitude ◽  
Last Glacial ◽  
Ice Cap ◽  
The Andes ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractIce cap modeling constrained by empirical studies provides an effective way of reconstructing past climates. The former Patagonian ice sheet is in a climatically significant location since it lies athwart the Southern Hemisphere westerlies and responds to the latitudinal migration of climatic belts during glacial cycles. A numerical model of the Patagonian ice cap for the last glacial maximum (LGM) is developed, which is time-dependent and driven by changing the mass balance/altitude relationship. It relies on a vertically integrated continuity model of ice mass solved over a finite difference grid. The model is relatively insensitive to ice flow parameters but highly sensitive to mass balance. The climatic input is adjusted to produce the best fit with the known limits of the ice cap at the LGM. The ice cap extends 1800 km along the Andes and has a volume of 440,000 km3. During the LGM the equilibrium line altitude (ELA) was lower than at present by at least 560 m near latitude 40°S, 160 m near latitude 50°S, and 360 m near latitude 56°S. The latitudinal variation in ELA depression can be explained by an overall fall in temperature of about 3.0°C and the northward migration of precipitation belts by about 5° latitude. Annual precipitation totals may have decreased by about 0.7 m at latitude 50°S and increased by about 0.7 m at latitude 40°S. The ELA rises steeply by up to 4 m per kilometer from west to east as the westerlies cross the Andes and this prevents ice growth to the east. The limited decrease in temperature during the LGM could be related to the modest migration of the Antarctic convergence between South America and the Antarctic Peninsula.

Timing of glacier advances and climate in the High Tatra Mountains (Western Carpathians) during the Last Glacial Maximum

2014 ◽  
Vol 82 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Michał Makos ◽  
Jan Dzierżek ◽  
Jerzy Nitychoruk ◽  
Marek Zreda
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Tatra Mountains ◽  
Last Glacial ◽  
Exposure Dating ◽  
Temperature And Precipitation ◽  
Southern Side ◽  
The Last Glacial Maximum ◽  
High Tatra Mountains ◽  
The Last Glacial

AbstractDuring the Last Glacial Maximum (LGM), long valley glaciers developed on the northern and southern sides of the High Tatra Mountains, Poland and Slovakia. Chlorine-36 exposure dating of moraine boulders suggests two major phases of moraine stabilization, at 26–21 ka (LGM I — maximum) and at 18 ka (LGM II). The dates suggest a significantly earlier maximum advance on the southern side of the range. Reconstructing the geometry of four glaciers in the Sucha Woda, Pańszczyca, Mlynicka and Velicka valleys allowed determining their equilibrium-line altitudes (ELAs) at 1460, 1460, 1650 and 1700 m asl, respectively. Based on a positive degree-day model, the mass balance and climatic parameter anomaly (temperature and precipitation) has been constrained for LGM I advance. Modeling results indicate slightly different conditions between northern and southern slopes. The N–S ELA gradient finds confirmation in slightly higher temperature (at least 1 °C) or lower precipitation (15%) on the south-facing glaciers during LGM I. The precipitation distribution over the High Tatra Mountains indicates potentially different LGM atmospheric circulation than at the present day, with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses.

scholarly journals Glacial geomorphology and cosmogenic 10Be and 26Al exposure ages in the northern Dufek Massif, Weddell Sea embayment, Antarctica

2012 ◽  
Vol 24 (4) ◽  
pp. 377-394 ◽  
Author(s):  
Dominic A. Hodgson ◽  
Michael J. Bentley ◽  
Christoph Schnabel ◽  
Andreas Cziferszky ◽  
Peter Fretwell ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Weddell Sea ◽  
Glacial Geomorphology ◽  
Last Glacial ◽  
Exposure Dating ◽  
Exposure Ages ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractWe studied the glacial geomorphology and geochronology of two ice-free valleys in the Dufek Massif (Antarctic Specially Protected Area 119) providing new constraints on past ice sheet thickness in the Weddell Sea embayment. 10Be and 26Al cosmogenic surface exposure dating provided chronological control. Seven glacial stages are proposed. These include an alpine glaciation, with subsequent (mid-Miocene?) over-riding by a warm-based ice sheet. Subsequent advances are marked by a series of minor drift deposits at 760 m altitude at > 1 Ma, followed by at least two later ice sheet advances that are characterized by extensive drift sheet deposition. An advance of plateau ice field outlet glaciers from the south postdated these drift sheets. The most recent advance involved the cold-based expansion of the ice sheet from the north at the Last Glacial Maximum, or earlier, which deposited a series of bouldery moraines during its retreat. This suggests at most a relatively modest expansion of the ice sheet and outlet glaciers dominated by a lateral ice expansion of just 2–3 km and maintaining a thickness similar to that of the northern ice sheet front. These observations are consistent with other reports of modest ice sheet thickening around the Weddell Sea embayment during the Last Glacial Maximum.

Continental/Cordilleran ice interactions: a dominant cause of westward super-elevation of the last glacial maximum continental ice limit in southwestern Alberta, Canada

2001 ◽  
Vol 30 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Edward C. Little ◽  
Lionel E. Jackson ◽  
Thomas S. James ◽  
Stephen R. Hicock ◽  
Elizabeth R. Leboe
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial
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