Tephra layers in the Dome Fuji (Antarctica) deep ice core

Abstract

A deep ice core drilled to 2503 m depth at Dome Fuji, Antarctica, contains 25 visible tephra layers during the past 340 ka. The thickness of tephra layers is in the range 1-24 mm. The thickness and duration at deposition, determined by a simple ice-flow model, suggests that a violent volcanic eruption caused ash to fall onto the Antarctic ice sheet for ~5 years and to form a ~100 mm thick tephra layer at 117 ka BP. Two tephra layers at depths of 573 and 2202 m probably originated from volcanoes in the South Sandwich Islands, Southern Ocean, given the size of tephra shards, >20 μm in diameter, and their major chemical composition. Only eight of the 25 tephra layers can also be recognized in the Vostok (Antarctica) ice core, but all correspond to the Vostok tephras if we consider cloudy bands to be volcanic.