Oxygen-18 content of atmospheric precipitation during last 11,000 years in the Great Lakes region |
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| Authors: | M Stuiver |
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| Abstract: | Freshwater lake marl and mollusks from Indiana show variations in ratios of oxygen-18 to oxygen-16 of a few per mil during the Postglacial. For the last 9000 years these variations are about 1 per mil for properly selected lake sediments. Thus the oxygen isotope composition of atmospheric precipitation appears relatively stable over this interval, indicating stationary atmospheric circulation patterns over the Great Lakes region. A reduction in oxygen-18 content around 10,000 years ago corresponds with the climate change indicated by pollen profiles. Large systematic differences were found between carbon-13 and oxygen-18 content of marl and mollusks. |
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