Towards a North Atlantic Plio-Pliestocene sediment color climate index

Abstract:

Sediment color variations at North Atlantic Site DSDP609/U1308 exhibit a very similar pattern to the water isotope record of the North GRIP ice core. Moving window cross correlation between NGRIP δ¹⁸O and sediment lightness (L*) reveals a consistently high and significant correlation. Based on this relationship, we construct a color-based climate index by calculating color reflectance values from the shipboard line-scanner images. Use of the line-scanner images provides a higher-resolution series (0.01 cm) than the 2-cm shipboard spectrophotometer data and permits for manual removal of disturbed pixels prior to analysis. At present, the composite benthic δ¹⁸O record at Site U1308 extends to MIS K2, providing age control beyond 3 Ma. Thus, we expect this to yield a near-continuous, centennial-scale record of 41-ky world interstadial-stadial variability back to Northern Hemisphere glacial inception.