The timing of Cordilleran Ice Sheet deglaciation along the central coast of British Columbia, Canada, informs climate forcing and early human migration. Thirty‐two ¹⁰Be exposure ages from glacial erratics and local bedrock on the western margin of the former ice sheet represent the earliest exposure ages for the Cordilleran Ice Sheet during the last deglaciation. These data show the western ice margin was retreating by 18.1 ± 0.2 ka, consistent with the global record of ice mass loss. In contrast, parts of the southern margin reached a maximum at ca. 17.6–16.6 ka, and our data demonstrate a diachronous response of the Cordilleran Ice Sheet during deglaciation. We also show that a low altitude site was exposed by at least 17.7 ± 0.3 ka, implying that numerous ice‐free areas existed along the coastal margin by this time, providing a viable route for the first humans entering the Americas.

Establishing the timing of glacial and nonglacial intervals in the core regions of the Laurentide Ice Sheet (LIS) is essential to constrain ice-sheet configuration at times of globally reduced ice volume, such as during Marine Isotope Stage (MIS) 3 (~57–29 ka). Hudson Bay Lowland (HBL) deglaciation, at the centre of the LIS, has been inferred at MIS 3 based on near-infinite wood radiocarbon ages and limited luminescence ages. To better constrain the age of the penultimate deglaciation of the western HBL, this study initially identified the youngest intertill nonglacial sediments, based on extensive fieldwork and till characterization. Next, vetted radiocarbon ages were combined with revised stratigraphy to show that five previously identified “MIS 3” sites were likely deposited during an earlier ice-free period. Finally, new optical ages targeting the youngest intertill nonglacial bed at three localities yielded ages ranging from 166 to 146 ka; all older than MIS 3. These ages indicate that the penultimate deglaciation of the western HBL likely occurred during MIS 5e. This interpretation better explains accompanying paleobotanic data sets that indicate vegetation similar to vegetation existing under present interglacial conditions. Currently no firm evidence exists in the terrestrial stratigraphic record for the deglaciation of the western HBL during MIS 3.

Late Pleistocene and Early Holocene aeolian deposits in Tasmania are extensive in the present subhumid climate zone but also occur in areas receiving >1000 mm of rain annually. Thermoluminescence, optically stimulated luminescence, and radiocarbon ages indicate that most of the deposits formed during periods of cold climate. Some dunes are remnants of longitudinal desert dunes sourced from now-inundated continental shelves which were previously semi-arid. Others formed near source, often in the form of lunettes east of seasonally-dry lagoons in the previously semi-arid Midlands and southeast of Tasmania, or as accumulations close to floodplains of major rivers, or as sandsheets in exposed areas. Burning of vegetation by the Aboriginal population after 40 ka is likely to have influenced sediment supply. A key site for determining climate variability in southern Tasmania is Maynes Junction which records three periods of aeolian deposition (at ca. 90, 32 and 20 ka), interspersed with periods of hillslope instability. Whether wind speeds were higher than at present during the last glacial period is uncertain, but shells in the Mary Ann Bay sandsheet near Hobart and particle size analysis of the Ainslie dunes in northeast Tasmania suggest stronger winds during the last glacial period than at present.

Laurentide Ice Sheet (LIS) reconstructions beyond the last glacial maximum (LGM) are difficult due to the incomplete stratigraphic record that has largely been eroded by the most recent glaciation. The Hudson Bay Lowland (HBL) is a key region to understanding the long-term evolution of the LIS, as it contains an extensive pre-LGM stratigraphic record of glacial and nonglacial events. This study uses a hybrid lithostratigraphy–allostratigraphy approach to decipher the stratigraphic record in the Kaskattama highland region of the western HBL, Manitoba, Canada. We identify five glacial (till) units and three nonglacial (sorted sediment) units that were deposited during at least three glacial–interglacial cycles, which are constrained by radiocarbon and optical ages. The provenance of till units is identified using clast-lithology and detrital hornblende ⁴⁰Ar/³⁹Ar ages and supported by matrix geochemistry. The new stratigraphic framework for this western HBL region indicates that the ice emanating from the Quebec–Labrador dome advanced into the region at the start of the last two glaciations, suggesting accelerated early growth of the Quebec–Labrador dome relative to the Keewatin Dome.