Late glacial climate evolution in the Patagonian Andes (44-47° S) from alpine glacier modelling

Muir, R., Eaves, S., Vargo, L., Anderson, B., Mackintosh, A., Sagredo, E., Soteres, R. L. “Late glacial climate evolution in the Patagonian Andes (44-47° S) from alpine glacier modelling”. Quaternary Science Reviews, 305, 108035.

Numerical glacier models applied to moraine chronologies provide an opportunity to quantify past climate change. Here we apply a two-dimensional coupled mass balance e ice flow model to well-dated moraine sequences deposited by former alpine glaciers at two central Patagonian sites: Cerro Riñ
on (43.97
S, 71.64
W) and Río Tranquilo (47.50
S, 72.38
W), to reconstruct the local temperatures during both the Antarctic Cold Reversal (14.7-13 ka) and the Younger Dryas (12.9-11 ka). Modelled temperature anomalies during the Antarctic Cold Reversal are 2.6 ± 0.4
C at 44
S, and 2.9 ± 0.6
C at 47
S. At both locations this cold event is followed by temperature increases of þ0.6e0.7
C or precipitation reductions of c. 20% to drive glacier retreat to moraines deposited during Younger Dryas time. The consistent climatic anomalies between these two latitudes suggest this region of Patagonia was responding to a common climatic event. Further, the late-glacial temperature anomalies found here compare well to those determined by similar glacier modelling techniques in New Zealand, at 43-44
S. These results support a trans-Pacific response throughout the southern mid to high latitudes (43-47
S) during the ACR that is best explained by a northward expansion of the south westerly winds.

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