A South Atlantic record of organic carbon export and ocean temperature after the Cretaceous/Tertiary (K/T) event

Author(s): Luttenberg, Danielle
Source: Institution: University of Rhode Island, Kingston, RI, United States
Note: In English. Master's thesis
Summary: A dramatic decrease in planktic-to-benthic carbon isotopic (δ13C) gradients occurs at open-marine Cretaceous/Tertiary (K/T) sequences world-wide. This suggests that the export of organic carbon from surface to deep waters was drastically reduced following the K/T boundary impact. To reconstruct planktic-to-benthic and interplanktic δ13C gradients, I picked planktic foraminifera and benthic foraminifera of the latest Cretaceous through early Paleocene interval of South Atlantic Deep Sea Drilling Project Site 528 for detailed carbon and oxygen isotopic analyses. These isotopic data were combined with fine carbonate and benthic foraminiferal data from D'Hondt and Lindinger (1988). These results indicate that in the South Atlantic interplanktic δ13C gradients collapsed after the K/T impact and did not recover until two million years later. Planktic-to-benthic δ13C gradients achieved partial recovery about 1 million years after the K/T impact, but, at least in this region, did not fully recover until almost three million years after the event. This suggests that, in the South Atlantic, the post-boundary recovery of the planktic-to-benthic δ13C gradient took far longer than previous estimates (which ranged from only a few thousand years to about two million years). There is no conclusive evidence for long-term changes in mean temperature after the K/T impact. However, it remains possible that our isotopic records were aliased by fine-scale variations in climate.
Year of Publication: 1997
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Benthic taxa; Carbon; Cenozoic; Cretaceous; DSDP Site 528; Deep Sea Drilling Project; Foraminifera; IPOD; Invertebrata; Isotope ratios; Isotopes; K-T boundary; Leg 74; Lower Paleocene; Marine environment; Mesozoic; Microfossils; O-18/O-16; Organic carbon; Oxygen; Paleocene; Paleoclimatology; Paleoecology; Paleogene; Paleotemperature; Planktonic taxa; Protista; South Atlantic; Stable isotopes; Stratigraphic boundary; Tertiary; Upper Cretaceous
Coordinates: S283130 S283129 E0021927 E0021926
Record ID: 2004037296
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.