Elemental analysis (TC, TOC, IC), Rock Eval Pyrolysis, and calcite and dolomite (XRD) data of sediment core PS72/291-2 (Beaufort Sea, Arctic Ocean)

Core PS72/291-2 (Mackenzie slope/southern Canada Basin; 71°16.18'N, 137°10.82'W; 1502 m of water depth) recovered during Polarstern Expedition PS72 (Jokat, 2009), consists of two lithological units (Stein et al., 2009). Unit I (0 – 152 cm) is characterized by three different types of sediment facies. Facies 1 is a bioturbated brown, grayish brown, and olive brown silty clay (representing post-glacial/Holocene pelagic sedimentation); Facies 2 (90 – 99 cm and 141 – 150 cm) is a dark grayish brown to grayish brown silty clay to sandy silty clay with abundant reddish brown ("pinkish") lenses/clasts and dropstones, and Facies 3 is characterized by dark gray to dark grayish brown laminated fine-grained (silty clay to clay; some sand) sediments. Unit II mainly consists of dark grayish brown, very dark gray to dark olive gray clay, intercalated with thin coarser-grained (silty) layers (fining-upward cycles). Occasionally, small pinkish gray lenses occur. The different sediment facies types were probably controlled by two different main processes. The dominantly dark gray to dark grayish brown silty clay to clay (fining-upward) cycles are interpreted as distal turbidites related to short-term periods of increased suspended matter supply by the Mackenzie River. The second important process of sediment transport towards the core location seems to be ice rafting. Phases of increased IRD input are reflected in the intervals characterized by a more coarse-grained facies with enrichment of pale brown and pinkish lenses/clasts (Stein et al., 2009). This very specific lithology can be related to a restricted source area in the Canadian Arctic (Bank Island, Victoria Island) where Paleozoic carbonates (dolomite) are cropping out (e.g., Phillips and Grantz, 2001; Stein et al., 2010), and it can be interpreted as pulses of increased iceberg discharge due to the disintegration of extended Canadian glacial ice sheets.