--> Evolution of the Danube Delta and Deepsea Fan in the Black Sea

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Evolution of the Danube Delta and Deepsea Fan in the Black Sea


A new sequence stratigraphic framework for the Pleistocene Danube Fan was constructed using high-resolution and conventional 2D seismic and high-resolution bathymetry. The Pleistocene Danube Fan was formed during the last sea level lowstand when the Danube River flowed into the Viteaz Canyon (Popescu et al. 2001). The fan had three stages of deposition: The first was a large mass transport complex (MTC). Next is the early fan which consists of an erosional slope canyon which fed a series of compensationally-stacked lobes deposited in the basin. These lobes are apparently sandy based on seismic facies. The late fan consists of thick muddy levees updip, and apparently sandy lobes downdip. Levee deposition extends updip nearly to the shelf edge, and the main levee reaches a maximum thickness of 600 m. The distal 2/3 of the fan is dominated by the deposits of channels, levees, and their associated sandy lobes with many avulsions. Proximal avulsions resulted in thick lobe deposits followed by the progradation of thick muddy levees (Popescu et al. 2001). Distal avulsions resulted in thinner lobe deposits that are prograded over by smaller, probably sandy, levees. Apparently only one channel was active at a time. Finally, as sea level rose, the fan was abandoned, and the distal area was onlapped by muddy turbidites coming from the Turkish shelf (Lericolais et al. 2015). Importantly, there are no hemipelagic drapes on the fan except for a 50-cm-thick sapropel and coccolith ooze. There are many generations of fans below the Late Pleistocene fan, each with a proximal single thick levee-confined-channel and many compensationally-stacked lobes in the distal basin. The fans are also area fed by canyons similar to the modern Viteaz Canyon. The oldest fan deposits lack a large channel/levee feeder, and are composed of small lobes. The oldest shelf edge associated with a northern sediment source in the western Black Sea is at approximately the location of the modern shoreline in its most proximal location. Lericolais, G., Bourget, J., Popescu, I., Jermannaud, P., Mulder, T., Jorry, S., Panin, N., 2015. Late Quaternary deep-sea sedimentation in the western Black Sea: New insights from recent coring and seismic data in the deep basin. Global and Planetary Change 103, 232–247. Popescu, I., Lericolais, G., Panin, N., Wong, H.K., Droz, L., 2001. Late Quaternary channel avulsions on the Danube Deep-Sea Fan. Marine Geology 179, 25–37.