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An unusually long and continuous Late Quaternary sedimentary sequence has been preserved in a sedimentary basin formed in the Sokli Carbonatite Massif in eastern-central Finnish Lapland. A nearly complete sediment recovery from the central Sokli basin combined with palynological results from sediments not earlier recovered and an independent OSL/AMS 14 C chronology allow us here to define the Late Quaternary climate-stratigraphy at Sokli and describe in detail the environmental record. Three interstadial intervals of Weichselian age are distinguished that correlate with MIS 5c, 5a and part of MIS 3 in the marine oxygen-isotope record. The interstadials of MIS 5c and 3 age are here defined as the Sokli and Tulppio Interstadials, respectively. The MIS 5a interstadial is correlated with the Maaselkä/Peräpohjola Interstadials of Finnish Lapland, which previously have been tentatively assigned a MIS 5c age. Till beds in the Sokli sequence (deposited during stadials 3-1) correlate to MIS 5b, 4 and 3/2, respectively. Depositional environments and vegetational changes during the ice-free intervals at Sokli are discussed. The Sokli sedimentary sequence indicates significantly less extensive and more variable ice-cover over Finnish Lapland during the Weichselian than has been earlier suggested based on the long-distance correlation of litho-and bio-stratigraphic fragmentary evidence.

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The sediment-landform associations of the northern Taymyr Peninsula in Arctic Siberia tell a tale of ice sheets advancing from the Kara Sea shelf and inundating the peninsula, probably three times during the Weichselian. In each case the ice sheet had a margin frozen to its bed and an interior moving over a deforming bed. The North Taymyr ice-marginal zone (NTZ) comprises ice-marginal and supraglacial landsystems dominated by thrust-block moraines 2-3 km wide and large-scale deformation of sediments and ice. Large areas are still underlain by remnant glacier ice and a supraglacial landscape with numerous ice-walled lakes and kames is forming even today. The proglacial landsystem is characterised by subaqueous (e.g. deltas) or terrestrial (e.g. sandar) environments, depending on location/altitude and time of formation. Dating results (OSL, 14 C) indicate that the NTZ was initiated ca. 80 kyr BP during the retreat of the Early Weichselian ice sheet and that it records the maximum limit of a Middle Weichselian glaciation (ca. 65 kyr BP). During both these events, proglacial lakes were dammed by the ice sheets. Part of the NTZ was occupied by a thin Late Weichselian ice sheet (20-12 kyr BP), resulting in subaerial proglacial drainage.

Glacial−interglacial variations in CO2 and methane in polar ice cores have been attributed, in part, to changes in global wetland extent, but the wetland distribution before the Last Glacial Maximum (LGM, 21 ka to 18 ka) remains virtually unknown. We present a study of global peatland extent and carbon (C) stocks through the last glacial cycle (130 ka to present) using a newly compiled database of 1,063 detailed stratigraphic records of peat deposits buried by mineral sediments, as well as a global peatland model. Quantitative agreement between modeling and observations shows extensive peat accumulation before the LGM in northern latitudes (>40°N), particularly during warmer periods including the last interglacial (130 ka to 116 ka, MIS 5e) and the interstadial (57 ka to 29 ka, MIS 3). During cooling periods of glacial advance and permafrost formation, the burial of northern peatlands by glaciers and mineral sediments decreased active peatland extent, thickness, and modeled C stocks by 70 to 90% from warmer times. Tropical peatland extent and C stocks show little temporal variation throughout the study period. While the increased burial of northern peats was correlated with cooling periods, the burial of tropical peat was predominately driven by changes in sea level and regional hydrology. Peat burial by mineral sediments represents a mechanism for long-term terrestrial C storage in the Earth system. These results show that northern peatlands accumulate significant C stocks during warmer times, indicating their potential for C sequestration during the warming Anthropocene.