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A fifth Vostok core was begun in 1990, reached 3661 m in 2007, and was later extended to 3769 m. [108] [113] The estimated age of the ice is 420,000 years at 3310 m depth; below that point it is difficult to interpret the data reliably because of mixing of the ice. [114] The EPICA Dome C and Vostok ice cores compared
Although the Vostok core reached a depth of 3,623 m the usable climatic information does not extend down this far. The very bottom of the core is ice refrozen from the waters of Lake Vostok and contains no climate information. The usual data sources give proxy information down to a depth of 3,310 m or 414,000 years. [35]
The picture shows delta deuterium data (a proxy for temperature: more negative values indicate lower temperatures) from both EPICA and Vostok. The upper plot, with x-axis being age (years before 1950) clearly shows the extra information in the EPICA core before the start of the Vostok record. The lower picture, plotted against depth, shows how ...
La originala priskribo estas: Graph of CO 2 (Green graph), temperature (Blue graph), and dust concentration (Red graph) measured from the Vostok, Antarctica ice core as reported by Petit et al., 1999. Higher dust levels are believed to be caused by cold, dry periods.
Nov. 4—GRAND FORKS — An international team of researchers containing UND geology professor Jaakko Putkonen, has uncovered what is believed to be the world's oldest ice core. The core, which ...
Graph of reconstructed temperature (blue), CO 2 (green), and dust (red) from the Vostok Station ice core for the past 420,000 years. To geologists, an ice age is defined by the presence of large amounts of land-based ice.
An ice core which contains samples of Earth’s atmosphere from five million years ago has been pulled up from the continent’s Ong Valley, researchers have said.
Reconstruction of the past 5 million years of climate history, based on oxygen isotope fractionation in deep sea sediment cores (serving as a proxy for the total global mass of glacial ice sheets), fitted to a model of orbital forcing (Lisiecki and Raymo 2005) [98] and to the temperature scale derived from Vostok ice cores following Petit et al ...