Evidence for the living ocean following the Cretaceous/Paleogene mass extinction

Author(s): Esmeray-Senlet, S.; Wright, J. D.; Olsson, R. K.; Miller, K. G.; Browning, J. V.
Author Affiliation(s): Primary:
Rutgers University, Piscataway, NJ, United States
Volume Title: AGU 2014 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2014; American Geophysical Union 2014 fall meeting, San Francisco, CA, Dec. 15-19, 2014. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The Cretaceous/Paleogene (K/Pg) mass extinction (∼66 Ma) was associated with a collapse in the carbon isotopic (δ13C) gradient between planktonic and benthic foraminifera and a decrease in bulk carbonate δ13C values. These perturbations have been attributed to three hypotheses: the Strangelove Ocean, with global collapse of primary productivity; the Living Ocean, with greatly reduced export but not primary productivity; and the Resilient Ocean, with persistent export productivity. While previous studies have focused on deep-sea locations, we tested the hypotheses in the paleo-continental shelf of New Jersey, USA, where δ13C values and organic carbon accumulation rates can distinguish among the hypotheses. We also evaluated interbasinal deep-sea δ13C differences between Ocean Drilling program (ODP) Sites 1210 (Shatsky Rise, North Pacific) and 1262 (Walvis Ridge, South Atlantic). New Jersey shelf shows that a ∼2.5 ppm δ13C drop in bulk carbonate, a collapse of the vertical δ13C gradient between planktonic and benthic foraminifera, and a significant decrease in organic carbon mass accumulation rates occurred across the K/Pg boundary. We interpret a ∼1.0 ppm water column δ13C gradient and cross-shelf benthic foraminiferal δ13C gradient in the early Danian to reflect the presence of active primary productivity, strongly supporting the Living Ocean hypothesis. Deep-sea δ13C differences between ODP Sites 1210 and 1262 show that the interbasinal deep-sea benthic foraminiferal δ13C gradient collapsed immediately after the mass extinction, which is consistent with a strong reduction in the export productivity after the K/Pg boundary. However, the ocean floor in highly productive regions like the equatorial Pacific may have continued to receive significant export productivity.
Year of Publication: 2014
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Cenozoic; Cretaceous; K-T boundary; Leg 198; Leg 208; Lower Paleocene; Mass extinctions; Mesozoic; North Pacific; Northwest Pacific; ODP Site 1210; ODP Site 1262; Ocean Drilling Program; Pacific Ocean; Paleocene; Paleogene; Shatsky Rise; South Atlantic; Stratigraphic boundary; Tertiary; Upper Cretaceous; Walvis Ridge; West Pacific
Coordinates: N321300 N321300 E1581600 E1581600
S271100 S271100 E0013500 E0013400
Record ID: 2015117277
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