Modeling variations of marine reservoir ages during the last 45 000 years

International audience When dating marine samples with 14 C, the reservoir-age effect is usually assumed to be constant, although atmospheric 14 C production rate and ocean circulation changes cause temporal and spatial reservoir-age variations. These lead to dating errors, which can limit the inter...

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Bibliographic Details
Main Authors: Franke, J., Paul, A., Schulz, M
Other Authors: Department of Geosciences
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2008
Subjects:
Online Access:https://hal.science/hal-00298205
https://hal.science/hal-00298205/document
https://hal.science/hal-00298205/file/cpd-4-81-2008.pdf
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Summary:International audience When dating marine samples with 14 C, the reservoir-age effect is usually assumed to be constant, although atmospheric 14 C production rate and ocean circulation changes cause temporal and spatial reservoir-age variations. These lead to dating errors, which can limit the interpretation of cause and effect in paleoclimate data. We used a global ocean circulation model forced by transient atmospheric ? 14 C variations to calculate reservoir ages for the last 45 000 years for a present day-like and a last glacial maximum-like ocean circulation. A ~30% reduced Atlantic meridonal overturning circulation leads to increased reservoir ages by up to ~500 years in high latitudes. Temporal variations are proportional to the absolute value of the reservoir age; regions with large reservoir age also show large variation. Temporal variations range between ~300 years in parts of the subtropics and ~1000 years in the Southern Ocean. For tropical regions, which are generally assumed to have nearly stable reservoir ages, the model suggests variations of several hundred years.