Palaeoenvironmental indications of a Late Weichselian ostracod assemblage from the southern Kattegat, Scandinavia

Vibrocore 9303 was drilled at a water depth of 35 m in the southern Kattega t and penetrated 10 m of Holocene and Late Weichselian sediments. The ostra cods recorded from 11 samples of this core in the time between c. 11,500 an d 10,500 BP are dominated by Elofsonella concinna, Sarsicytheridea punctill ata, Cytheropteron dimlingtonensis, Roundstonia globulifera, Acanthocythere is dunelmensis, Sarsicytheridea bradii, Cytheropteron macchesneyi, Robertso nites tuberculatus, freshwater spp., and Heterocyprideis sorbyana. Most of these species are autochthonous (not freshwater spp.) based on their popula tion age structures. The maximum bottom-water temperature probably ranged f rom 8 to 12 degrees C during summer. The palaeoenvironment was probably mar ine sublittoral with depths exceeding 10-15 m. The time interval between c. 10,900 and 10,650 BP is marked by (1) an increase in ostracod species dive rsity, (2) a decrease in dominance of the three most abundant ostracod spec ies, (3) a replacement of A. dunelmensis by C. macchesneyi and (4) freshwat er species become more abundant. These changes may possibly be due to an in creased niche availability and/or sea-level changes associated with a stron ger influence of freshwater to the in situ environment. However, the change s in species composition are statistically insignificant according to a boo tstrap correspondence analysis.