Radiocarbon dating of archived sediment cores in the Southeast Pacific from 1960 to 2000

Abstract

There were likely large changes in Southeast (SE) Pacific Ocean biogeochemistry over the last glacial cycle as a consequence of coincident changes in dust flux, oxygenation, and latitudinal position of the Subantarctic and Antarctic Fronts. However, there are few available sediment core records with reliable chronologies for this time interval despite the large number of archived cores collected between the 1960s and 1990s. The apparent reason is that, except for sites in proximity to the South American continental margin, sedimentation rates are often lower than 1 cm/kyr and calcium carbonate is only well preserved on topographic highs. As part of a project to study past nitrogen fixation, we surveyed archived cores from the SE Pacific and selected the most promising for radiocarbon dating of the planktonic foraminiferal fraction. While many cores have core tops were found to be older than detectable with radiocarbon, a number have core tops ages within the Holocene and sediment accumulation rates centering on 1.5 cm/kyr.

For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/886679