Microfaunal Abundance Fluctuations in the Western Black Sea (Romanian Offshore, Cretaceous to Pliocene)
Marius Dan Georgescu, 2003. "Microfaunal Abundance Fluctuations in the Western Black Sea (Romanian Offshore, Cretaceous to Pliocene)", Micropaleontologic Proxies for Sea-Level Change and Stratigraphic Discontinuities, Hilary Clement Olson, R. Mark Leckie
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Variations in microfaunal abundance are a useful tool in recognizing basin evolutionary stages. The Western Black Sea basin, situated near a continental passive margin, has three evolutionary phases: flysch, filling, and shelf sedimentation. Flysch sediments accumulated after basin rifting and contain rare and sporadic microfossils. During the filling phase, mostly turbidite sediments accumulated. Their microfossil record shows mixed, rather poor assemblages in periods with increased terrigenous input, but the assemblages are rich in hemipelagic sediments at the tops of turbidite sequences. The most diverse and abundant assemblages occur in sediments of the shelf sedimentation phase. During a basin evolutionary stage, microfaunal abundance shows a gradual upward increase, reaching highest values at the top. A tentative correlation with the supercycles of the Haq et al. (1988) chart is made. This correlation shows that a microfaunal abundance peak is situated in the lower proximity of a supercycle top in the Haq et al. (1988) chart.