A review of Glacial and Holocene paleoclimate records from southernmost Patagonia (49–55°S)

Abstract

Southern South America is the only landmass intersecting the southern westerly wind belt (SWW) that influences the large-scale oceanography and controls for example the outgassing of CO2 in the Southern Ocean. Therefore, paleo-reconstructions from southernmost Patagonia are of global interest and an increasing number of paleoclimate records have been published during the last decades. We provide an overview on the different records mostly covering the Holocene but partly extending into the Late Glacial based on a large variety of archives and proxies. We particularly discuss possible reasons for regionally diverging palaeoclimatic interpretations and summarize potential climate forcing mechanisms. The Deglacial and Holocene temperature evolution of the region including the adjacent Pacific Ocean indicates “Antarctic” pattern and timing consistent with glacier re-advances during the Antarctic Cold Reversal. Some records indicate a significant accumulation control on the glacier fluctuations related to changes in SWW strength and/or position. Reconstructions of Holocene changes in the SWW behaviour provide partly inconsistent and controversially discussed pattern. While records from the hyperhumid side point to a stronger or southward displaced SWW core during the Early Holocene thermal maximum, records from the lee-side of the Andes show either no long term trend or the opposite, suggesting enhanced westerlies during the late Holocene “Neoglacial”. Likewise, centennial-scale global or hemispheric cold intervals, such as the Little Ice Age, have been interpreted in terms of enhanced and reduced SWW strength. Some SWW variations can be linked to changes in the El Niño-Southern Oscillation (ENSO) consistent with instrumental climate data-sets and might be ultimately forced by solar variability. Resolving these inconsistencies in southernmost Patagonian SWW records is a prerequisite for improving hemispheric comparisons and links to atmospheric CO2 changes.