New estimates of the magnitude of the sea-level jump during the 8.2 ka event

We analyzed sediment cores from coastal Lake Izabal, Guatemala, to infer Holocene biogeochemical changes in the lake. At ca. 8370 calibrated yr B.P. (cal. yr B.P.), marine waters entered the lake, which presently lies similar to 38 km from the Caribbean coast. Temporal correlation between Early Holocene drainage of high-latitude Lakes Agassiz and Ojibway (in North America) and marine flooding of Lake Izabal suggests a causal link between the two processes. Our data indicate a relative sea-level jump of 2.60 +/- 0.88 m, which is larger than previous estimates of sea-level rise during the 8.2 ka event. The inferred sea-level jump, however, cannot be explained solely by the volume of water released during drainage of Lakes Agassiz and Ojibway. Instead, we propose that previous studies underestimated the magnitude of Lakes Agassiz and Ojibway discharge, or that additional meltwater sources contributed to global sea-level rise at that time.