(Table 1) Calcium carbonate abundance in ODP Leg 164 sites


Diffuse reflectance spectra measured during shipboard core description with a hand-held Minolta spectrophotometer are reliable data for interpreting sediment composition. Factor analysis of these spectra indicates that only Glad Cling WrapTM, a polyethylene food wrap, should be used to cover wet cores during measurement because it introduces substantially less noise into the spectra than other brands of plastic food wrap. This validates our previous recommendation that only Glad Cling WrapTM should be used to cover wet core surfaces before spectral analysis on board ship. Factor analysis also indicates that the red end of the spectrum was a little noisy; however, it is unclear if this noise was produced by the Glad Cling WrapTM, by the Minolta instrument, or by the sediment being analyzed when wet (water tends to affect the red end of the spectrum more than the violet). Comparison of spectra taken directly from wet cores on board ship with the Minolta CM-2002 to those taken from dried, prepared samples with our shore-based Perkin-Elmer Lambda 6 spectrophotometer indicates that water mutes the spectral signal. Although factor analysis of the Perkin-Elmer data produced five factors, four of those factors are the same as the factors extracted from the wet core data with the Minolta. This suggests that the water content in the wet cores was not high enough to seriously hinder interpretation of sediment composition. These four common factors are interpreted as carbonate, chlorite or glauconite, organic matter, and iron oxides (probably a mixture of hematite and goethite). The presence of hematite can be attributed to hematite-rich sediment derived from the Canadian Maritime provinces, which has been transported southward by the Western Boundary Undercurrent (WBUC) along North American continental margin. Based on the distribution of hematite down the Leg 164 holes, the WBUC apparently has washed over the Leg 164 sites on the crest of the Blake Ridge only during the Holocene and very latest Pleistocene.

Supplement to: Balsam, William L; Damuth, John E (2000): Further investigations of shipboard vs. shore-based spectral data: implications for interpreting Leg 164 sediment composition. In: Paull, CK; Matsumoto, R; Wallace, PJ; Dillon, WP (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 164, 1-12

DOI https://doi.org/10.1594/PANGAEA.804401
Related Identifier https://doi.org/10.2973/odp.proc.sr.164.222.2000
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.804401
Creator Balsam, William L; Damuth, John E
Publisher PANGAEA
Publication Year 2000
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 645 data points
Discipline Earth System Research
Spatial Coverage (-76.191W, 31.786S, -75.469E, 32.984N); South Atlantic Ocean; Nicaraguan Rise, North Atlantic Ocean
Temporal Coverage Begin 1995-11-05T12:22:00Z
Temporal Coverage End 1995-12-10T00:10:00Z