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Evidence for shelf acidification during the onset of the Paleocene-Eocene Thermal Maximum

October 12, 2018

A transect of paleoshelf cores from Maryland and New Jersey contains a ~0.19 m to 1.61 m thick interval with reduced percentages of carbonate during the onset of the Paleocene-Eocene Thermal Maximum (PETM). Outer paleoshelf cores are barren of nannofossils and correspond to two minor disconformities. Middle paleoshelf cores contain a mixture of samples devoid of nannofossils and those with rare specimens characterized by significant dissolution (i.e., etching). The magnitude of the decrease in carbonate cannot be explained by dilution by clastic material or dissolution resulting from the oxidation of organic matter during early diagenesis. The observed preservation pattern implies a shoaling of the calcite compensation depth (CCD) and lysocline to the middle shelf. This reduced carbonate interval is observed during the onset of the PETM on other continental margins raising the possibility that extreme shoaling of the CCD and lysocline was a global signal which is more significant than in previous estimates for the PETM. An alternative scenario is that shoaling was restricted to the northwest Atlantic, enhanced by regional and local factors (eutrophication from rivers, microbial activity associated with warming) that exacerbated the impact of acidification on the shelf.

Publication Year 2019
Title Evidence for shelf acidification during the onset of the Paleocene-Eocene Thermal Maximum
DOI 10.1029/2018PA003382
Authors Timothy J. Bralower, Lee R. Kump, Marci M. Robinson, Jean Self-Trail, Shelby L. Lyons, Tali Babila, Edward Ballaron, Katherine H. Freeman, Elizabeth A. Hajek, William Rush, James C. Zachos
Publication Type Article
Publication Subtype Journal Article
Series Title Paleoceanography and Paleoclimatology
Index ID 70203053
Record Source USGS Publications Warehouse
USGS Organization Eastern Geology and Paleoclimate Science Center