18. Data Report: High-Resolution Stable Isotope Records across the Paleocene/Eocene Boundary, ODP Sites 1220 and 1221¹

Flavia Nunes² and Richard D. Norris²

ABSTRACT

High-resolution carbon and oxygen isotope records were produced from 240 analyses of two species of benthic foraminifers and bulk carbonate in sediments from across the Paleocene/Eocene (P/E) boundary in Ocean Drilling Program (ODP) Holes 1220B and 1221C. Although part of the carbon isotope excursion is not recorded in either Hole 1220B or Hole 1221C because of carbonate dissolution, both sites do record a significant part of the main geochemical excursion. The benthic foraminifers from Hole 1220B are believed to provide reliable geochemical records of the magnitude of the P/E excursion as judged by the quality of foraminifer preservation and similarity of the carbon isotope record to that seen at other deep-sea sites. However, anomalously positive values in the benthic ¹⁸O record in sediments from Hole 1221C and bulk carbonate in sediments from Hole 1220B indicate that diagenesis masks the primary isotopic signature in this part of the records. The Paleocene–Eocene Thermal Maximum is only observed in the Hole 1220B benthic foraminifer records, with a ¹⁸O excursion of –0.65 to –0.85. The magnitude of the carbon isotope excursion is as much as 0.96 in Hole 1221C and 2.01 in Hole 1220B. Although smaller than at Southern Ocean Site 690 (2.6), the carbon isotope excursion in Hole 1220B is of similar magnitude to that observed in Deep Sea Drilling Project and ODP Sites 527, 738, and 1051 and the Alamedilla Section in Spain (–2.1, –1.6, –1.9, and –1.7, respectively).

¹Nunes, F., and Norris, R.D., 2005. Data report: High-resolution stable isotope records across the Paleocene/Eocene boundary, ODP Sites 1220 and 1221. In Wilson, P.A., Lyle, M., and Firth, J.V. (Eds.), Proc. ODP, Sci. Results,199: College Station, TX (Ocean Drilling Program), 1–12. doi:10.2973/odp.proc.sr.199.206.2005

²Scripps Institution of Oceanography, 9500 Gilman Drive, MC 0208, La Jolla CA 92092, USA. Correspondence author: fnunes@ucsd.edu

Initial receipt: 30 March 2004
Acceptance: 31 January 2005
Web publication: 15 December 2005
Ms 199SR-206