Tables in support of "Antarctic response to orbital forcing during the intensification of extensive bipolar glaciation (1.75-3.30 Ma) from relative paleomagnetic intensity (RPI) stratigraphy of the Dove Basin, Scotia Sea"

Supplementary tables in support of Reilly, et al. 2026. Antarctic Response to Orbital Forcing During the Intensification of Extensive Bipolar Glaciation (1.75–3.30 Ma) From Relative Paleomagnetic Intensity Stratigraphy of the Dove Basin, Scotia Sea. Paleoceanography and Paleoclimatology 41, e2025PA005360. https://doi.org/10.1029/2025PA005360

Abstract

The sediments of “Iceberg Alley,” north of the Weddell Sea Embayment of Antarctica, are a key archive of Antarctic Ice Sheet and Southern Ocean history but are challenging to date at orbital timescales due to lack of foraminifera. We present a relative paleomagnetic intensity (RPI) chronology for sediments deposited across the Pliocene-Pleistocene Transition (3.14–1.75 Ma) at Dove Basin, International Ocean Discovery Program (IODP) Sites U1536 and U1537. Leveraging the well-defined magnetizations of these deep-sea contourite deposits, for the first time we correlate a Dove Basin RPI proxy to a North Atlantic RPI template that is intercalibrated with benthic δ18O and lithologic signals that record the history of Northern Hemisphere glaciation intensification (iNHG) from ∼2.7 Ma. Our new RPI chronology demonstrates a close relationship between sedimentation rates and physical lithology, with high accumulation occurring at times of high biogenic silica concentrations. This relationship is found at both long periods that reflect the amplitude modulation of orbital forcing and at glacial-interglacial timescales. Moreover, the chronology indicates a transition in the pacing of lithologic variability during iNHG from having greater precession-paced variations than benthic δ18O prior to 2.8 Ma and obliquity-paced variations after 2.6 Ma that are nearly identical to benthic δ18O. A clear and persistent influence of precession, especially during extreme early Pleistocene interglacial intervals (high biogenic silica and high accumulation rates) nevertheless persisted during times of high variance in both precession and obliquity forcing—most notable during Marine Isotope Stages 87, 89, and 91.

Table S1. Target Curves generated from Sites U1308, U1314, and U1396 for 16502800 ka with uncertainty.

Table S2. Revised age control points for Site U1314, following the approach described in the text.

Table S3. Summary of u-channel data.

Table S4. Dove Basin RPI proxy stack, using the natural remanent magnetization (NRM) after 15 mT peak AF demagnetization, normalized by magnetic susceptibility (k).

Table S5. Dove Basin Magnetic Susceptibility stack on depth.

Table S6. Age model constraints for Site U1537.

Table S7. Undatable age-depth model results. Table S8. Physical Properties data on age.

Table S9. U1537 sedimentation rates calculated in 10 kyr bins.