![]() ![]() Reference Hammer, Clausen and DansgaardHammer and others, 1980) and/or as visible ash layers. They also provide a detailed record of local and distal volcanic eruptions as acidity peaks due to high concentrations of H 2SO 4, HCl and HF (e.g. Ice cores drilled from the polar ice sheets can provide key information about the mechanism of global circulation of these volcanic products. They eventually fall to the Earth’s surface through complex physico-chemical processes. The volcanic gases are converted into aerosols of sulfuric acid, and these acidic components mix with fine ash and are globally distributed. ![]() Large amounts of volcanic ash and gases are emitted to the upper troposphere and stratosphere during explosive volcanic eruptions. A clear correlation was found for the chemical compositions of six of these ash layers, indicating a high potential for key correlation beds between the deep ice cores from Dome Fuji and Vostok. A comparison of profiles of 18O/ 16O (δ 18O) and 2H/ 1H (δD) for the Dome Fuji and Vostok cores indicates that eight ash layers are equivalent in the two cores. In order to correlate between ice cores from Dome Fuji and Vostok, Antarctica, which are widely separated, we found coeval ash layers serving as stratigraphic markers of Antarctic ice cores. Abundances of trace elements for the alkaline tephra collected from one layer revealed a possible genetic link to volcanic rocks from Marie Byrd Land. The tephras found in the other five ash layers were significantly smaller (< 5 μm), suggesting that they traveled over longer distances. The source regions appear to be (1) South Sandwich Islands, Southern Ocean, (2) South Shetland Islands, Antarctica, and/or a southern part of the volcanic zone of the Andes, and (3) Marie Byrd Land and/or Victoria Land, Antarctica, respectively. On the basis of comparison of the major-element compositions of these tephras with reference to volcanic rocks and ash, the tephras were divided into three types: (1) tholeiitic basalt to dacite, (2) calc-alkaline andesite, and (3) trachyandesite to trachyte. ![]() The particles found in 21 of the 26 layers were commonly a few tens of μm in size, suggesting that they originated from volcanoes located in and around the Antarctic. In order to gain information about the sources of ash particles found in the layers, major and trace element abundances have been measured. Twenty-six ash layers were found in a 2503 m deep ice core from Dome Fuji station, East Antarctica. ![]()
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