During Ocean Drilling Program Leg 199 a high-resolution (~1–2 cm/k.y.) biogenic sediment record from the late Paleocene to the early Miocene was recovered, containing an uninterrupted set of geomagnetic chrons as well as a detailed record of calcareous and siliceous biostratigraphic datum events. Shipboard lithologic proxy measurements and shore-based determinations of CaCO3 revealed regular cycles that can be attributed to climatic forcing. Discovering drill sites with well defined magneto- and biostratigraphic records that also show clear lithologic cycles is rare and valuable and creates the opportunity to develop a detailed stratigraphic intersite correlation, providing the basis to study paleoceanographic processes and mass accumulation rates at high resolution.
Here we present extensive postcruise work that extends the shipboard composite depth stratigraphy by providing a high-resolution revised meters composite depth (rmcd) scale to compensate for depth distortion within individual cores. The depth-aligned data were then used to generate stacked records of lithologic proxy measurements. Making use of the increased signal-to-noise ratio in the stacked records, we then proceeded to generate a detailed site-to-site correlation between Sites 1218 and 1219 in order to decrease the depth uncertainty for magneto- and biostratigraphic datums. Stacked lithologic proxy records in combination with discrete measurements of CaCO3 were then exploited to calculate high-resolution carbonate concentration curves by regression of the multisensor track data with discrete measurements. By matching correlative features between the cores and wireline logging data, we also rescaled our core rmcd back to in situ depths. Our study identifies lithology-dependent core expansion due to unloading as the mechanism of varying stratigraphic thicknesses between cores.
1Pälike, H., Moore, T., Backman, J., Raffi, I., Lanci, L., Parés, J.M., and Janecek, T., 2005. Integrated stratigraphic correlation and improved composite depth scales for ODP Sites 1218 and 1219. In Wilson, P.A., Lyle, M., and Firth, J.V. (Eds.), Proc. ODP, Sci. Results,199: College Station, TX (Ocean Drilling Program), 1–41. doi:10.2973/odp.proc.sr.199.213.2005
2Southampton Oceanography Centre, School of Ocean and Earth Science, European Way, Southampton SO14 3ZH, UK. email@example.com
3Geological Sciences, University of Michigan, 2534 C.C. Little Building, 425 East University Avenue, Ann Arbor MI, 48109-1063, USA.
4Deptartment of Geology and Geochemistry, Stockholm University, 10691 Stockholm, Sweden.
5Dipartimento di Scienze della Terra, Universitario "G. D'Annunzio," Campus Universitario, Via dei Vestini 31, 66013 Chieti Scalo, Italy.
6Istituto di Dinamica Ambientale, Universita' di Urbino Localita Crocicchia, 61029 Urbino, Italy.
7Deptartment of Geological Sciences, Rutgers University, Piscataway NJ 08854, USA.
8IODP Management International, Inc., 1899 L Street, Northwest, Suite 200, Washington DC 20036, USA.
Initial receipt: 19 April 2004
Acceptance: 16 November 2004
Web publication: 2 June 2005