THE MAGNITUDE AND RAPIDITY OF THE CLIMATE CHANGE MARKING THE END OF THE PLEISTOCENE IN THE MIDLATITUDES OF SOUTH-AMERICA

The chi-squared test of independence and cluster analysis of Otsuka si milarity coefficients of fossil beetle assemblages from the Chilean La ke Region in the mid-latitudes of South America support the following conclusions: (1) the mean summer temperature of the glacial climate wa s 4-5-degrees-C lower than today's climate; (2) the climatic change fr om glacial to interglacial mode was in a single step centered on about 14,000 yr B.P.; (3) the climatic change was rapid, and within 1500 ye ars the biota of a moorland had been completely replaced by a biota of a rain forest; (4) by 12,500 yr B.P., the low elevation beetle fauna of the Chilean Lake Region was similar in composition to that of the p resent day; and (5) no reversal in the postglacial warming trend, equi valent in age to the Younger Dryas Stade, was detected.