Ostracoda in five sediment cores from the Laptev and Kara seas

Fossil ostracods were investigated in five AMS14C-dated cores from different parts of the Laptev and Kara seas. Three cores from the Laptev Sea shelf are located in river paleovalleys, and one core originates from the western continental slope. The core from the Kara Sea was obtained in the eastern shelf region. Six fossil assemblages were distinguished: estuarine (1), inner-shelf (2), middle-shelf (3), outer-shelf (4), Pre-Holocene upper continental slope (5), and Holocene upper continental slope (6). They show that during the Postglacial sea-level rise there was a transition from estuarine brackish-water environment to modern marine conditions. Assemblages 1-3 are present in the eastern Laptev Sea with the oldest ostracod-bearing samples aging back to 11.4-11.3 cal.ka. Cores from the western Laptev Sea (12.3 cal.ka, assemblages 1-4) and the Kara Sea (8.1 cal.ka, assemblages 2-4) demonstrate similar pattern in assemblage replacement, but contain a number of relatively deep-water species reflecting stronger influence of open-sea waters. […]