RECORD OF VOLCANISM SINCE 7000-BC FROM THE GISP2 GREENLAND ICE CORE AND IMPLICATIONS FOR THE VOLCANO-CLIMATE SYSTEM

Sulfate concentrations from continuous biyearly sampling of the GISP2 Greenland ice core provide a record of potential climate-forcing volca nism since 7000 B.C. Although 85 percent of the events recorded over t he last 2000 years were matched to documented volcanic eruptions, only about 30 percent of the events from 1 to 7000 B.C. were matched to su ch events. Several historic eruptions may have been greater sulfur pro ducers than previously thought. There are three times as many events f rom 5000 to 7000 B.C. as over the last two millennia with sulfate depo sition equal to or up to five times that of the largest known historic al eruptions. This increased volcanism in the early Holocene may have contributed to climatic cooling.