Constructing an accurate age model for Pleistocene sediments is crucial for our understanding of glacial cycles and other climatic processes. Benthic foraminiferal δ18O stacks, a proxy for ice sheet and climate evolution, are often used for stratigraphic alignment of deep-sea sedimentary records beyond the range of radiocarbon. Selection of a benthic δ18O alignment target influences the resulting chronology, and divergent regional trends in benthic δ18O highlight the need for ocean-specific benthic δ18O stacks. The scientific question to be addressed by a study may also influence whether the age model used should include orbital tuning. Here, we introduce three benthic δ18O stacks – Atlantic, Pacific, and global, with three versions of chronology for the global stack that incorporate orbital forcing to various degrees. The global stack incorporates data from 224 cores and 50% more data than ProbStack (Ahn et al., 2017). The hand-tuned regional and global stacks, intended as updates to the LR04 stack (Lisiecki and Raymo, 2005), incorporate chronologies transferred from absolutely dated archives during 0-654 thousand years ago (ka) and an orbitally forced ice model during 654-2700 ka. Due to the heterogeneous nature of the age constraints used for these stacks, we call them BIGSTACKmixed, BIGSTACKmixedP, and BIGSTACKmixedA. For applications where orbital tuning should be avoided, we present an untuned global stack, BIGSTACKuntuned. We also develop a minimally tuned stack age model, BIGSTACKauto, which uses an automated algorithm to maximize the spectral power in obliquity. These stacks offer the paleoceanographic community flexibility in choosing stratigraphic alignment targets that best suit their needs.
This work is currenlty in prep. and soon to be submitted to Geochronology. We have made an interactive webpage to preview the BIGSTACKs. The five stacks are also available for download: BIGSTACKuntuned, BIGSTACKauto, BIGSTACKmixed, BIGSTACKmixedP, BIGSTACKmixedA