The sediments in the Santa Barbara Basin off California are well known for their high-resolution record of climatic variability in the eastern Pacific Ocean. Color density logs were extracted with a resolution of 11 measurements/millimeter sediment from digital images taken of all of the cores at Ocean Drilling Program Site 893. Processing of the data sets to eliminate (gas) voids and cracks allowed reconstruction of the original time series as deposited on the seafloor before drilling. The new depth scales result in a 13% reduction of the curated core length. Interhole comparison of the color density time series suggests a substantial shift of 2.9 m between Holes 893A and 893B. The shift is most likely due to a loss of material from the top of Hole 893A. The comparison of color density logs and CaCO3/total-organic-carbon data sets with a sample spacing between 20 cm, 5 cm, and 5 mm showed color control mostly by TOC for low-frequency oscillations (>50 yr), whereas high-frequency oscillations in sediment color are controlled by noncarbon components, which indicates a different response of fluxes to low- and high-frequency climatic forcing. Fourier transformation of the time series yielded distinct spectral peaks for two solar activity cycles and El Niño Southern Oscillations. These high-frequency cycles are not expressed in differences of organic matter production/preservation or carbonate flux to the sediment. The large-scale color (and TOC) trends after the glacial Cold Stage II termination correlate with the eustatic sea-level rise as recorded in coral reefs.
Date of initial receipt: 16 August 1994
Date of acceptance: 7 March 1995
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