Data report: IODP Site U1523 composite section and stratigraphic splice based on X-ray fluorescence data

Abstract

Contribution of melting Antarctic Ice Sheets (AIS) to rising sea level remains one of the least quantified inputs to models for the future. To improve these estimates, International Ocean Discovery Program (IODP) Expedition 374 cored five sites in the Ross Sea, Antarctica to examine the stability of the AIS to past intervals of global warmth. While most sites consisted of a single hole, Site U1523 cored 3 holes with overlapping stratigraphy in an attempt to recover as complete of a stratigraphic section as possible despite challenging coring conditions due to the presence of gravel lags and indurated intervals. Given these challenges, no attempt was made to create a composite depth scale or stratigraphic splice during the expedition. Here we use a combination of physical property data (primarily magnetic susceptibility and natural gamma radiation), X-ray fluorescence core scanning, and visual core description to construct a core composite depth below seafloor (CCSF) to the base of Hole U1523B. This composite depth scale is discontinuous due to challenging coring conditions and variable core recovery, although there are several intervals of reasonably good stratigraphic continuity between 0 and 26 m CCSF and 82 and 96 m CCSF. We also created a stratigraphic splice from 0 to 93.95 m CCSF, although the splice is only continuous to 15.82 m CCSF. Additionally, we mapped the off-splice interval of Core U1523E-1H to the composite depth scale over several intervals with significant core disturbance by stretching and squeezing to obtain a best fit. Development of the composite depth scale and stratigraphic splice will improve post-cruise research results by allowing scientists to compare samples from different holes on the same depth scale.