Variability of sea ice cover in the Chukchi Sea (western Arctic Ocean) during the Holocene

摘要: [1] Dinocysts from cores collected in the Chukchi Sea shelf edge to lower slope were used reconstruct changes sea surface conditions and ice cover using modern analogue techniques. Holocene sequences have been recovered a down-slope core (B15: 2135 m, 75°44′N, sedimentation rate of ∼1 cm kyr−1) (P1: 201 73°41′N, ∼22 kyr−1). The record spanning about 8000 years suggests high-frequency centennial oscillations significant reduction at circa 6000 2500 calendar (cal) B.P. condensed offshore (B15) reveals an early postglacial optimum with minimum prior 12,000 cal B.P., which corresponds terrestrial climate Bering area. Dinocyst data indicate extensive (>10 months yr−1) followed by general trend decreasing increasing salinity conditions, superimposed on large-amplitude millennial-scale oscillations. In contrast, δ18O mesopelagic foraminifers (Neogloboquadrina pachyderma) benthic (Cibicides wuellerstorfi) reveal maximum subsurface temperature thus inflow North Atlantic water around toward cooling bottom masses. Sea-surface estimated dinocysts suggest decoupling between layer intermediate mass existence sharp halocline reverse thermocline, especially before overall reconstructions B15 are consistent strong convergence western Arctic during as suggested basis model experiments including dynamics, matching higher Water.