The distribution of ice-rafted detritus in piston cores (8 to 17 m long) from siliceous oozes in the northwest Pacific indicates that up to six major zones of ice-rafted sediment were deposited during the Brunhes normal epoch. The easily recognizable detritus first appeared after the end of the Gauss magnetic epoch about 2.2 m.y. ago and was relatively rare until about 1.5 m.y. ago, but became particularly abundant during the last million years. The rafted material consists mainly of altered or zeolitized intermediate to basic volcanic rocks and associated sediments rich in volcanic detritus probably derived from the Kurile-Kamchatka-Aleutian arc. The distribution and abundance of the rafted detritus suggests that currents responsible for distribution of icebergs in the Pleistocene were similar to those that exist today.