Age-Depth Models for Tropical Marine Hemipelagic Deposits Improve Significantly When Proxy-Based Information on Sediment Composition Is Included

Accurate age-depth models for marine sediment cores are crucial for understanding paleo-oceanographic and -climatic changes derived from these archives. To date, information on bulk sediment composition is largely ignored as a potential source of information to improve age-depth models. In this study, we explore how bulk sediment composition can be qualitatively used to improve age-depth models. We developed the BomDia algorithm, which produces age-depth models with realistic sediment accumulation rates that co-vary in harmony with the bulk sediment composition. We demonstrate that changes in the marine versus terrigenous sediment deposition, based on bulk sediment composition, can be used to significantly improve age-depth models of hemipelagic marine deposits. Based on two marine records-each containing more than 20 radiocarbon (AMS C-14) dated levels-we show that the mean error of prediction of unused AMS C-14 ages significantly improves from 3.9% using simple linear interpolation, to 2.4% (p = 0.003), when bulk sediment composition is included. The BomDia age-depth modeling approach provides a powerful statistical tool to assess the validity of age control points used and also may assist in the detection of hiatuses. Testing and further development of the BomDia algorithm may be needed for application in depositional settings other than tropical hemipelagic.

Automated summary

In this study, the BomDia algorithm was developed to improve age-depth models using bulk sediment composition as a potential source of information. The algorithm demonstrated significant improvements in predicting the ages of marine deposits compared to traditional linear interpolation methods.