Response of chironomids to Late Quaternary environmental change in the Taitao Peninsula, southern Chile

MASSAFERRO; BROOKS

JOURNAL OF QUATERNARY SCIENCE

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2002 vol. 17 p. 101 - 111

0267-8179

There is conflicting evidence concerning the extent and timing of late Quaternary climate variability in southern South America and how this may be linked to climate change in the Northern Hemisphere. Critical unresolved questions include whether or not a cool period occurred in southern South America during the Younger Dryas Chronozone (YDC) (11 000?10 000 14C yr BP; 13 000?11 200 yr BP), and the timing of wet and dry phases during the Holocene. To date most evidence is from glacial, pollen and beetle records but, in an attempt to resolve these questions, we have used chironomid midges as an independent proxy in one of the first studies of its kind in Patagonia. We investigated the dynamics of midge assemblages during the Late-glacial and Holocene at Lago Stibnite on the Taitao Peninsula, southern Chile (46°S). Changes in the midge assemblage suggest that the climate may have become cooler and drier during the YDC. During the Holocene there were cyclical changes in the midge assemblage that may have been in response to trophic change and/or to changes in precipitation when conditions appear to have been drier than today at 9400?6300 14C yr BP and 2400?1600 14C yr BP. Copyright  2002 John Wiley & Sons, Ltd.