Evidence for an abrupt change in climate close to 11,000 years ago

Abstract

Evidence from a number of geographically isolated systems suggests that the warming of world-wide climate which occurred at the close of Wisconsin glacial times was extremely abrupt. Surface ocean temperatures in the Atlantic Ocean increased by several degrees centigrade, and deep-sea sedimentation rates sharply decreased in the equatorial Atlantic. The bottom waters of the Cariaco trench, a restricted basin in the Caribbean, abruptly stagnated. The pluvial lakes in the Great Basin rapidly shrank from their maximum volume to nearly their present size. Silty clay which was flushed into the Gulf of Mexico during the glacial period was suddenly retained in the alluvial valley and delta of the Mississippi River and the glacially-dammed Great Lakes drainage was returned to the northern outlet. As indicated by pollen profiles a pronounced warm period in northwestern Europe also occurred at this time. In each case the radiocarbon age determinations suggest that the changes occurred in less than 1,000 years close to 11,000 years ago.