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AGU: Paleoceanography

 

Keywords

  • paleoproductivity proxies
  • carbon isotopes
  • geochemistry

Index Terms

  • Biogeosciences: Paleoclimatology and paleoceanography
  • Paleoceanography: Micropaleontology
  • Oceanography: Biological and Chemical: Carbon cycling
  • Paleoceanography: Isotopic stage
  • Paleoceanography: Biogeochemical cycles, processes, and modeling
Abstract
Cited By (2)
 

Abstract

Late Miocene carbon isotope records and marine biological productivity: Was there a (dusty) link?

Liselotte Diester-Haass

Zentrum für Umweltwissenschaften, Universität des Saarlandes, Saarbrücken, Germany

Katharina Billups

College of Marine and Earth Studies, University of Delaware, Lewes, Delaware, USA

Kay C. Emeis

Institut für Biogeochemie und Meereschemie, Universität Hamburg, Hamburg, Germany

We examine whether or not a relationship exists between the late Miocene carbon isotope shift (∼7.6–6.6 Ma) and marine productivity at four sites from the Indian and Pacific Oceans (Ocean Drilling Program Sites 721, 1146, 1172, and 846). We use a multiproxy approach based on benthic foraminiferal accumulation rates, elemental ratios, and dissolution indices, and we compare these data to benthic foraminiferal δ 13C values measured on the same samples. Although some of these sites have been targeted previously in studies of either the late Miocene/early Pliocene “biogenic bloom” (Sites 721 and 846) or the late Miocene carbon isotope shift (Site 1172), our records are the first to establish paired proxy records of carbon isotopes and paleoproductivity allowing a direct assessment of a potential link. Our results indicate that at all sites, productivity increased sometime during the δ 13C shift; at three sites (721, 1146, and 846), productivity increased at the beginning of the shift. The correlation coefficients derived from linear regression between micropaleontologically derived productivity and foraminiferal δ 13C values are relatively high during the time interval containing the late Miocene δ 13C shift (and statistically significant at three of the sites). Carbon flux and isotope mass balance considerations illustrate that transfer of organic matter between the terrestrial and marine reservoirs together with enhanced oceanic upwelling best approximates observed changes in carbon isotope records and paleoproductivity. We note that long-term trend in the Site 846 paleoproductivity record can be correlated to the long-term trend in the Site 848 eolian flux reconstructions of Hovan (1995) hinting at a link between strengthened wind regime and productivity during the late Miocene.

Received 10 January 2006; accepted 19 July 2006; published 15 December 2006.

Citation: Diester-Haass, L., K. Billups, and K. C. Emeis (2006), Late Miocene carbon isotope records and marine biological productivity: Was there a (dusty) link?, Paleoceanography, 21, PA4216, doi:10.1029/2006PA001267.

Cited By

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