CTD and bathymetric profile (Fig. S1) Detailed views of the location of the CTD (white) and bathymetric (red) profiles presented in the manuscript (Figs. 3 and 10).CTD stations are shown as white dots, and coring stations as yellow dots.The CTD profile intersects 11-GC on the outer sill instead of 10-GC, and does not cross the maximum sill depths on either the inner or outer fjord.The bathymetric profile follows the deepest channel beneath the ice tongue to avoid introducing artefacts that would otherwise appear to be steps in the seafloor morphology.Again, the profile does not pass through the maximum sill depth at the head of Sherard Osborn Fjord before reaching the restricted inner embayment.9 4.53 0 4.53 3 139 4.28 9 5.01 49 5.01
Abstract International Ocean Discovery Program (IODP) Expedition 382 in the Scotia Sea’s Iceberg Alley recovered among the most continuous and highest resolution stratigraphic records in the Southern Ocean near Antarctica spanning the last 3.3 Myr. Sites drilled in Dove Basin (U1536/U1537) have well‐resolved magnetostratigraphy and a strong imprint of orbital forcing in their lithostratigraphy. All magnetic reversals of the last 3.3 Myr are identified, providing a robust age model independent of orbital tuning. During the Pleistocene, alternation of terrigenous versus diatomaceous facies shows power in the eccentricity and obliquity frequencies comparable to the amplitude modulation of benthic δ 18 O records. This suggests that variations in Dove Basin lithostratigraphy during the Pleistocene reflect a similar history as globally integrated ice volume at these frequencies. However, power in the precession frequencies over the entire ∼3.3 Myr record does not match the amplitude modulation of benthic δ 18 O records, suggesting Dove Basin contains a unique record at these frequencies. Comparing the position of magnetic reversals relative to local facies changes in Dove Basin and the same magnetic reversals relative to benthic δ 18 O at North Atlantic IODP Site U1308, we demonstrate Dove Basin facies change at different times than benthic δ 18 O during intervals between ∼3 and 1 Ma. These differences are consistent with precession phase shifts and suggest climate signals with a Southern Hemisphere summer insolation phase were recorded around Antarctica. If Dove Basin lithology reflects local Antarctic ice volume changes, these signals could represent ice sheet precession‐paced variations not captured in benthic δ 18 O during the 41‐kyr world.
SUMMARY International Ocean Drilling Program (IODP) Expedition 341 recovered sediments from the south Alaska continental slope that preserves a well resolved and dated inclination record over most of the past ∼43 000 yr. The Site U1419 chronology is among the highest resolution in the world, constrained by 173 radiocarbon dates, providing the ability to study Palaeomagnetic Secular Variation (PSV) on centennial to millennial timescales. This record has an exceptionally expanded late Pleistocene sedimentary record with sedimentation rates commonly exceeding 100 cm kyr–1, while also preserving a lower resolution Holocene PSV record at the top. Natural and laboratory-induced magnetic remanences of U1419 u-channels from the 112-m-long spliced record were studied using stepwise AF demagnetization. Hysteresis loops were obtained on 95 and IRM acquisition curves on 9 discrete samples to facilitate magnetic domain state, coercivity and magnetic mineralogical determinations. Due to complexities related to lithology, magnetic mineralogy, and depositional and post-depositional processes, Site U1419 sediments are not suitable for palaeointensity studies and declination could not be robustly reconstructed. Progressive (titano-)magnetite dissolution with depth results in decreasing NRM intensity and signal-to-noise that is exacerbated at higher demagnetization steps. As a result, inclination measured after the 20 mT AF demagnetization step provides the most reliable directional record. Inclination appears to be well resolved with removal of just a few intervals influenced by depositional and/or sampling and coring deformation. The shipboard inclination stack from nearby IODP Site U1418, on a new age model developed from 19 radiocarbon dates on U1418 and 18 magnetic susceptibility-based tie-points to site survey core EW0408-87JC, verifies centennial to millennial scale variations in inclination observed in U1419. Comparisons with other independently dated records from the NE Pacific and western North America suggest that these sites likely capture regional geomagnetic variability. As such, this new high-resolution and well-dated inclination record, especially robust between 15 and 30 cal kyr BP, offers new geomagnetic insights and a regional correlation tool to explore this generally understudied part of the world.
In summer 2023, the Baffin Bay Deglacial Experiment (BADEX) completed a 33-day cruise focused on the west Greenland margin; the overarching goal of this project is to investigate the evolving ocean and ice conditions along the west Greenland ice sheet from the last glacial maximum through the deglaciation. The cruise collected seafloor and sub-seafloor data, as well as water and plankton samples, with the aim of establishing 1) the timing and extent of warm Atlantic water incursion along the north-western Greenland margin; 2) the phasing of the initial ice margin retreat relative to oceanic and atmospheric changes; 3) the role of local or regional ice shelves in buttressing trough-bound outlet glaciers; and 4) the influence of regional geology, geomorphology, and ice dynamics on ice-margin retreat. Here, we present results from the ~600 km of new multibeam sonar data collected on the slope just north of the Melville Bugt trough mouth fan (TMF). The margin in this area curves landward, forming a crescent-shaped, submarine amphitheater that contains a range of bathymetric features, which vary in form with water depth and their proximity to the TMF. This includes a series of contour-following ridges that occur in depths from ~1000 to ~450 meters below modern water level. These ridges are more prominent farther away from the TMF but are more numerous closer to the trough. They are interpreted to be of glaciogenic origin, potentially formed by an ice shelf, fed by the trough, that flowed to the north and grounded on the slope. These ridges and other bathymetric features, extending up to 2000 meters water depth will be discussed. These results add to our understanding of the ice margin configuration in northern Baffin Bay during and after the last glacial period.  
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