The Variability of Holocene Climate Change: Evidence from Varved Lake Sediments

Authors

Walter E. Dean, U.S. Geological Survey, Denver, COFollow
J. Platt Bradbury, U.S. Geological Survey
Roger Y. Anderson, University of New MexicoFollow
Cathy Barnosky, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania

Date of this Version

12-7-1984

Comments

Published in Science, New Series, Vol. 226, No. 4679 (Dec. 7, 1984), pp. 1191 -1194.

Abstract

Varved sediments from a lake near the present forest-prairie border in northwestern Minnesota provide an annual record of climate change for the last 10,400 years. Climate-sensitive mineral, chemical, and biological components show that the mid-Holocene dry interval between 8500 and 4000 years ago is asymmetrical and actually consists of two distinct drier pulses separated by a moister interval that lasted about 600 years. Cyclic fluctuations with periods of several hundred years were abrupt and persistent throughout the Holocene and are most clearly recorded within the two drier pulses.