USA Margin PETM

Mid-Atlantic U.S. Coastal Plain, USA

Location map of the mid-Atlantic Coastal Plain (MACP) and ODP Site 690.

The project targets to expanded PETM section and CIE deposits in the mid-Atlantic U.S. coastal plain. This is an area where marine sections recording the CIE (expanded onset and core/body, Marlboro clay) are rather thick, reaching > 10 m, in contrast to generally thin (< 1 m) sections elsewhere in the world. The project aims to triple-core the sections of interest at ten sites in 3 transects, building on the previous drilling in New Jersey by ODP Leg 174AX and Maryland-Virginia by the USGS, which sampled across the paleoshelf from inner neritic to deep neritic (>100 m) paleodepths. Existing cores are either depleted or contain stratigraphic gaps. Other Eocene hyperthermals and the Cretaceous/Paleogene (K/Pg) boundary at these sites will also be cored and sampled.

The objectives to be addressed are as follows:
1) utilize the high-sedimentation rates of the Marlboro Clay to evaluate the rapidity of the onset and lead-lag relationships of carbon injection, temperature rise, and sedimentation changes;
2) evaluate the relationship between extraterrestrial impact and climate;
3) study the biotic effects of the PETM on the paleoshelf, with a postulated major deoxygenation in thermocline and bottom waters, an eukaryote “black out” due to excessive temperatures, and the development of an unusual nannofossil assemblage suggestive of photic zone acidification.

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