Volcanic triggering of late Pliocene glaciation: evidence from the flux ofvolcanic glass and ice-rafted debris to the North Pacific Ocean

Mass accumulation rates (MAR) of different components of North Pacific deep -sea sediment provide detailed information about the timing of the onset of major Northern Hemisphere glaciation that occurred at 2.65 Ma. An increase in explosive volcanism in the Kamchatka-Kurile and Aleutian arcs occurred at this same time, suggesting a link between volcanism and glaciation. Sedi ments recovered by piston-coring techniques during ODP Lea 145 provide a un ique opportunity to undertake a detailed test of this possibility. Here we use volcanic glass as a proxy for explosive volcanism and ice-rafted debris (IRD) as a proxy for glaciation. The MAR of both glass and IRD increase ma rkedly at 2.65 Ma. Further, the flux of the volcanic glass increased just p rior to the flux of ice-rafted material, suggesting that the cooling result ing from explosive volcanic eruptions may have been the ultimate trigger fo r the mid-Pliocene glacial intensification. (C) 2001 Elsevier Science B.V. All rights reserved.