Chironomid and pollen evidence for climate fluctuations during the Last Glacial

MASSAFERRO, J.I., MORENO, P.I.,.DENTON, G.H, VANDERGOES, M, DIEFFENBACHER-KRALL, A

QUATERNARY SCIENCE REVIEWS

Elsevier

Año: 2009 vol. 28 p. 518 - 525

0277-3791

Abstract We present a chironomid record from the Huelmo site (~41°30´S), NW Patagonia, to examine in detail the timing and structure of climate changes during the Last Glacial Termination in the southern mid-latitudes. This record has the highest temporal and taxonomic resolution for this critical interval, and constitutes the first account of midge faunas at the culmination of the Last Glacial Maximum (LGM) for the region. The record suggests cold and wet LGM climate, followed by deglacial warming starting at 17.6 cal kyr BP. Relatively warm conditions prevailed between ~15-14 cal kyr BP, followed by a reversal in trend with cooling pulses at ~14 and 13.5 cal kyr BP, and warming at the beginning of the Holocene. Cool-temperate conditions prevailed during the Huelmo Mascardi Cold Reversal (HMCR) which, according to chironomid data, exhibits a wet phase (13.5-12.8 cal kyr BP) followed by a conspicuous drier phase (12.8-11.5 cal kyr BP). Our results indicate step-wise deglacial warming beginning at 17.6 cal kyr BP, in agreement with paleoclimate records from NW Patagonia and isotopic records from Antarctic ice cores. Peak warmth during the Last Glacial Termination was achieved by ~14.5 cal kyr BP, followed by a cooling trend that commenced during the Antarctic Cold Reversal, which later intensified and persisted during the HMCR (13.5-11.5 cal kyr BP). We observe a shift toward drier conditions superimposed upon this intensification, coeval with intense fire activity and vegetation disturbance during Younger Dryas time. examine in detail the timing and structure of climate changes during the Last Glacial Termination in the southern mid-latitudes. This record has the highest temporal and taxonomic resolution for this critical interval, and constitutes the first account of midge faunas at the culmination of the Last Glacial Maximum (LGM) for the region. The record suggests cold and wet LGM climate, followed by deglacial warming starting at 17.6 cal kyr BP. Relatively warm conditions prevailed between ~15-14 cal kyr BP, followed by a reversal in trend with cooling pulses at ~14 and 13.5 cal kyr BP, and warming at the beginning of the Holocene. Cool-temperate conditions prevailed during the Huelmo Mascardi Cold Reversal (HMCR) which, according to chironomid data, exhibits a wet phase (13.5-12.8 cal kyr BP) followed by a conspicuous drier phase (12.8-11.5 cal kyr BP). Our results indicate step-wise deglacial warming beginning at 17.6 cal kyr BP, in agreement with paleoclimate records from NW Patagonia and isotopic records from Antarctic ice cores. Peak warmth during the Last Glacial Termination was achieved by ~14.5 cal kyr BP, followed by a cooling trend that commenced during the Antarctic Cold Reversal, which later intensified and persisted during the HMCR (13.5-11.5 cal kyr BP). We observe a shift toward drier conditions superimposed upon this intensification, coeval with intense fire activity and vegetation disturbance during Younger Dryas time. examine in detail the timing and structure of climate changes during the Last Glacial Termination in the southern mid-latitudes. This record has the highest temporal and taxonomic resolution for this critical interval, and constitutes the first account of midge faunas at the culmination of the Last Glacial Maximum (LGM) for the region. The record suggests cold and wet LGM climate, followed by deglacial warming starting at 17.6 cal kyr BP. Relatively warm conditions prevailed between ~15-14 cal kyr BP, followed by a reversal in trend with cooling pulses at ~14 and 13.5 cal kyr BP, and warming at the beginning of the Holocene. Cool-temperate conditions prevailed during the Huelmo Mascardi Cold Reversal (HMCR) which, according to chironomid data, exhibits a wet phase (13.5-12.8 cal kyr BP) followed by a conspicuous drier phase (12.8-11.5 cal kyr BP). Our results indicate step-wise deglacial warming beginning at 17.6 cal kyr BP, in agreement with paleoclimate records from NW Patagonia and isotopic records from Antarctic ice cores. Peak warmth during the Last Glacial Termination was achieved by ~14.5 cal kyr BP, followed by a cooling trend that commenced during the Antarctic Cold Reversal, which later intensified and persisted during the HMCR (13.5-11.5 cal kyr BP). We observe a shift toward drier conditions superimposed upon this intensification, coeval with intense fire activity and vegetation disturbance during Younger Dryas time. examine in detail the timing and structure of climate changes during the Last Glacial Termination in the southern mid-latitudes. This record has the highest temporal and taxonomic resolution for this critical interval, and constitutes the first account of midge faunas at the culmination of the Last Glacial Maximum (LGM) for the region. The record suggests cold and wet LGM climate, followed by deglacial warming starting at 17.6 cal kyr BP. Relatively warm conditions prevailed between ~15-14 cal kyr BP, followed by a reversal in trend with cooling pulses at ~14 and 13.5 cal kyr BP, and warming at the beginning of the Holocene. Cool-temperate conditions prevailed during the Huelmo Mascardi Cold Reversal (HMCR) which, according to chironomid data, exhibits a wet phase (13.5-12.8 cal kyr BP) followed by a conspicuous drier phase (12.8-11.5 cal kyr BP). Our results indicate step-wise deglacial warming beginning at 17.6 cal kyr BP, in agreement with paleoclimate records from NW Patagonia and isotopic records from Antarctic ice cores. Peak warmth during the Last Glacial Termination was achieved by ~14.5 cal kyr BP, followed by a cooling trend that commenced during the Antarctic Cold Reversal, which later intensified and persisted during the HMCR (13.5-11.5 cal kyr BP). We observe a shift toward drier conditions superimposed upon this intensification, coeval with intense fire activity and vegetation disturbance during Younger Dryas time. ~41°30´S), NW Patagonia, to examine in detail the timing and structure of climate changes during the Last Glacial Termination in the southern mid-latitudes. This record has the highest temporal and taxonomic resolution for this critical interval, and constitutes the first account of midge faunas at the culmination of the Last Glacial Maximum (LGM) for the region. The record suggests cold and wet LGM climate, followed by deglacial warming starting at 17.6 cal kyr BP. Relatively warm conditions prevailed between ~15-14 cal kyr BP, followed by a reversal in trend with cooling pulses at ~14 and 13.5 cal kyr BP, and warming at the beginning of the Holocene. Cool-temperate conditions prevailed during the Huelmo Mascardi Cold Reversal (HMCR) which, according to chironomid data, exhibits a wet phase (13.5-12.8 cal kyr BP) followed by a conspicuous drier phase (12.8-11.5 cal kyr BP). Our results indicate step-wise deglacial warming beginning at 17.6 cal kyr BP, in agreement with paleoclimate records from NW Patagonia and isotopic records from Antarctic ice cores. Peak warmth during the Last Glacial Termination was achieved by ~14.5 cal kyr BP, followed by a cooling trend that commenced during the Antarctic Cold Reversal, which later intensified and persisted during the HMCR (13.5-11.5 cal kyr BP). We observe a shift toward drier conditions superimposed upon this intensification, coeval with intense fire activity and vegetation disturbance during Younger Dryas time.