Jiménez Berrocosco, Álvaro; MacLeod, Kenneth G; Martin, Ellen E; Bourbon, Elodie; Isaza-Londoño, Carolina; Basak, Chandranath (2010): Neodymium isotope ratios of fish debris from late Cretaceous black shales [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.792598, Supplement to: Jiménez Berrocosco, Á et al. (2010): Nutrient trap for Late Cretaceous organic-rich black shales in the tropical North Atlantic. Geology, 38(12), 1111-1114, https://doi.org/10.1130/G31195.1
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Abstract:
Neodymium isotopes of fish debris from two sites on Demerara Rise, spanning ~4.5 m.y. of deposition from the early Cenomanian to just before ocean anoxic event 2 (OAE2) (Cenomanian-Turonian transition), suggest a circulation-controlled nutrient trap in intermediate waters of the western tropical North Atlantic that could explain continuous deposition of organic-rich black shales for as many as ~15 m.y. (Cenomanian-early Santonian). Unusually low Nd isotopic data (epsilon-Nd(t) ~-11 to ~-16) on Demerara Rise during the Cenomanian are confirmed, but the shallower site generally exhibits higher and more variable values. A scenario in which southwest-flowing Tethyan and/or North Atlantic waters overrode warm, saline Demerara bottom water explains the isotopic differences between sites and could create a dynamic nutrient trap controlled by circulation patterns in the absence of topographic barriers. Nutrient trapping, in turn, would explain the ~15 m.y. deposition of black shales through positive feedbacks between low oxygen and nutrient-rich bottom waters, efficient phosphate recycling, transport of nutrients to the surface, high productivity, and organic carbon export to the seafloor. This nutrient trap and the correlation seen previously between high Nd and organic carbon isotopic values during OAE2 on Demerara Rise suggest that physical oceanographic changes could be components of OAE2, one of the largest perturbations to the global carbon cycle in the past 150 m.y.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 9.349494 * Median Longitude: -54.638545 * South-bound Latitude: 9.265510 * West-bound Longitude: -54.733050 * North-bound Latitude: 9.433333 * East-bound Longitude: -54.543880
Date/Time Start: 2003-01-22T00:00:00 * Date/Time End: 2003-02-12T23:45:00
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets
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Datasets listed in this publication series
- Jiménez Berrocosco, Á; MacLeod, KG; Martin, EE et al. (2010): (Table DR2) Stable carbon isotope and neodymium isotope ratios of fish debris from ODP Site 207-1258. https://doi.org/10.1594/PANGAEA.792597
- Jiménez Berrocosco, Á; MacLeod, KG; Martin, EE et al. (2010): (Table DR1) Stable carbon isotope and neodymium isotope ratios of fish debris from ODP Site 207-1260. https://doi.org/10.1594/PANGAEA.792596