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.
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Micropaleontology and biostratigraphy play vital roles for deciphering the stratigraphic record produced by changes in relative sea level, interpreting the history of global sea-level change, and testing models for the causes of sea-level fluctuations due to the variable influences of tectonics, glacio-eustasy, and climate. The stratigraphic architecture developed in response to changing eustasy, accommodation space, and sediment supply along continental margins, in epicontinental seas, and on carbonate platforms can be interpreted using the tools of marine micropaleontology. Microfossils provide chronostratigraphic control and a wealth of paleoenvironmental information about depositional environments as well as post-depositional changes to those environments. This volume demonstrates clearly that micropaleontologic proxies of environmental change provide a powerful dimension to the interpretive potential of stratigraphic sequences produced by changes in relative sea level and eustasy. Studies in the volume range from paralic to bathyal environments, span Pennsylvanian through Holocene stratigraphy, encompass a variety of microfossil groups and include a wide spectrum of techniques and paleoenvironmental proxies. The volume has been designed for graduate students and professionals interested in a wide range of subjects.