Holocene paleoecology and paleoceanography of the southwestern Black Sea shelf revealed by ostracod assemblages

摘要: Abstract The Holocene replacement of Ponto-Caspian ostracod assemblages by Mediterranean species is studied in two long composite cores, M02-45 (a cores M02-45P, M02-45 T and M05-03P) M05-50 M05-50P M05-51G), acquired at sites −69 m −91 m deep on the southwestern Black Sea shelf. Composite core was collected from middle shelf distal fringe eastern levee a saline underflow channel emanating Strait Bosphorus. Sixteen radiocarbon dates nine are used to construct age models, which show recovery sediments as old 12,915 cal yr BP (M02-45 site) 12,010 cal yr (M05-50 site). A total 45 identified cores. From ~12,000 ~7425 cal yr BP, assemblage dominated species, mainly Loxoconcha sublepida, L. lepida Tyrrhenocythere amnicola donetziensis. ~7425 ~6315 cal yr consists nearly equal abundances (Cytheroma variabilis M02-45; Sagmatocythere littoralis M05-50) species. After tops including Palmoconcha agilis, Carinocythereis carinata, Hiltermannicythere rubra Pterygocythereis jonesii. Cluster analysis further subdivides stratigraphic succession into six bioecozones with different assemblages. changes one bioecozone next indicate that progressive environmental took place least 7500 cal yr present. first hint changing conditions ~7500 cal yr lags initial reconnection through Bosphorus ~2000 yr, demonstrating salinity increased slowly reach values tolerable marine immigrants. Widespread colonization even longer, ~3000 years time reconnection.