47 Advances in Paleoclimate from the Terrestrial Realm to the Deep Sea

Wednesday, 14 March 2007
8:15 AM - 12:00 PM

VEGETATION AND WATER LEVEL CHANGES FOR THE NORTHEAST DURING THE 8.2 KA EVENT

Paper number: 47-9
Program: THEME SESSIONS
Time: 10:35 AM – 10:55 AM

Authors

Abstract

Cool conditions, known as the 8.2 ka event, occurred between 8400 and 7900 cal yr B.P. in Greenland, Europe and elsewhere in the North Atlantic. The impact of this brief interval is recorded in radiocarbon-dated, high-resolution pollen stratigraphies and sediments from lakes and mires within the Plymouth-Carver aquifer in southeastern Massachusetts. Within this aquifer, at New Long Pond (41.050'N 70.042'W), the 8.2 ka event is a brief (50 yr) interval preceded by a low-stand in water-level during the early Holocene and dominated by white pine pollen. After 9000 cal yr B.P., pitch pine with beech, maple, hop/hornbeam, elm and ash pollen indicate a mixed mesophytic forest. A radiocarbon-dated decrease in loss-on-ignition values at 8400 cal yr B.P. distinguishes the 8.2 event and helps highlight subtle shifts in vegetation that favor colder and drier conditions than before the event. After 8000 cal yr B.P., values for beech and changes in other pollen taxa increased across southern New England, signaling a return to warm and moist conditions until about 5600 years ago. In general, pollen evidence for the “8.2 ka event” may be easily overlooked within the longer-term trend toward warm conditions that shows more profound consequences for vegetation.