GEOLOGY
STRATIGRAPHY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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by studying the fossils buried in the ice
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by studying the location and depth of the ice
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by studying the composition of the frozen water
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by studying the atmospheric gases trapped in the ice
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Detailed explanation-1: -By measuring the ratios of different water isotopes in polar ice cores, we can determine how temperature in Antarctica and Greenland has changed in the past.
Detailed explanation-2: -By looking at past concentrations of greenhouse gasses in layers in ice cores, scientists can calculate how modern amounts of carbon dioxide and methane compare to those of the past, and, essentially, compare past concentrations of greenhouse gasses to temperature.
Detailed explanation-3: -The icy layers also hold particles-aerosols such as dust, ash, pollen, trace elements and sea salts-that were in the atmosphere at that time. These particles remain in the ice thousands of years later, providing physical evidence of past global events, such as major volcanic eruptions.
Detailed explanation-4: -Analysis of ice cores can also tell us about the amount of carbon dioxide in the atmosphere over the past 800, 000 years. This is accomplished by running meltwater from the cores through a gas chromatograph, which gives the carbon dioxide concentration in the trapped air.