Data report: IODP Site U1387: the revised splice between Sections U1387B-18X-3 and U1387C-8R-3 (>171.6 mcd)

Abstract

The Expedition 339 shipboard splice of Integrated Ocean Drilling Program (IODP) Site U1387 deeper than ~155 meters composite depth (mcd) is based on a composite of the magnetic susceptibility and natural gamma radiation data. When generating high-resolution paleoceanographic reconstructions for the Mid-Pleistocene Transition and early Pleistocene sections of Site U1387, it quickly became obvious that proxy data misfits existed at several splice transitions. Thus, a revised splice was generated for Site U1387 below Core 339-U1387B-18X based on X-ray fluorescence–derived element records (e.g., ln[Fe/Ca]) and the stable isotope records obtained for planktonic and benthic foraminifers. Corrections were needed at most of the splice transitions below Core 339-U1387A-19X, with adjustments ranging from a few centimeters to several meters. In addition, Core 339-U1387A-33X and sections of Core 36X were integrated into the revised splice to replace Core 339-U1387C-2R and sections of Core 5R, respectively. The replacement of Core 339-U1387C-2R with Core 339-U1387A-33X is an option for the intended paleoceanographic research and not essential for lower resolution studies. The splice tie point table, therefore, also includes an option for a splice that retains Core 339-U1387C-2R. The extensive revision of the shipboard splice reveals that making a splice for sediment sequences rich in contourite layers and coring disturbances (biscuiting in the extended core barrel cores) can be tricky and that data misfits at splice transitions are not necessarily a data problem but could indicate a splice problem.