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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
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.
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]
Note that the Vostok core is deeper, but does not extend as far back in time. Note also that the y-axis offset between the EPICA and Vostok cores in delta-deuterium is real: Vostok is a colder site, hence has more negative delta. Differences in the apparent age of events are likely to be inaccuracies in converting ice depth to age. Date: 20 ...
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.
At the present, the atmosphere is sampled routinely and complete annual averages are available. From the four ice cores presented on this plot the sampling varies from as rapid as one point every few years (recent parts of the Law Dome record) to as sparse as one sample every few thousand years (oldest parts of the Vostok and Dome C records).
The core, which Putkonen estimates is between 4 and 5 million years old, was discovered during a 2018 expedition in Antarctica. He said the 10 meter-long core contains invaluable information for ...
Oh there's much more involved than CO2 alone, which was just varying by a hundred ppm here. It isn't the primary driver of the ice age cycle. This graph is kind of misleading actually if you see it in isolation. Over thousands of years, Earth's orbit, tilt, and precession varies a bit in a pattern that initiates ice ages.