Tracking the sea-level signature of the 8.2 ka cooling event: New constraints from the Mississippi Delta

Abstract

The ever increasing need for accurate predictions of global environmental change under greenhouse conditions has sparked immense interest in an abrupt, century‐scale cooling around 8200 years ago, with a focal point in the North Atlantic and with hemispheric teleconnections. Despite considerable progress in the unraveling of this striking feature, including a conceivable driving mechanism (rapid drainage of proglacial Lake Agassiz/Ojibway and a resulting reduced strength of North Atlantic thermohaline circulation), several key questions remain unanswered. One salient aspect concerns the total amount of freshwater released during this catastrophic event, likely echoed by a near‐instantaneous eustatic sea‐level rise. So far, no attempts have been made to perform high‐resolution sea‐level studies that explicitly focus on this critical time interval. Here, we present new data from the Mississippi Delta suggestive of abrupt sea‐level rise associated with the 8.2 ka event. However, the amount of sea‐level rise was likely less than ∼1.2 m, corresponding to a meltwater volume of less than ∼4.3 1014 m3; values lower than estimates used by several recent studies

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