Haliç (Istanbul) kiyi alanlarinda (Unkapani-Azapkapi) gözlenen Holosen çökelleri hakkinda yeni bulgular

In Istanbul, a number of boreholes have been drilled on coastal areas and in the sea reaching up to Paleozoic basement, for a bridge construction in Golden Horn in the circumstances of Yenikapi-Taksim Subway Project during January-April 1999 period. 33 sediment samples were evaluated from HK-4, HK-5, HK-15, HK-17 and HK-18 wells located at the north and south coastal areas. The thickness of the 7400 year Holocene deposits varies between 14 and 30 m. In general, muds at the bottom of the sequence include vermes tubes and Ostrea. This unit is overlain by thick sands with pebbles. The presence of gray-grizzle sands with small pebbles indicate the barrier occurrence at the margin of the channel system. This part is overlain by green-beige, fine-grained sands with shell fragments indicating the flood plain deposits. A thick debris mixed deposits of shell, coal and brick fragments occurs at the uppermost part of the sequence. With 22 genus and 33 species of foraminifera were determined in young deposits. The most important findings obtained from the sediments are the presence of Sorites orbiculus Ehrenberg between 9 and 3 m intervals of borehole HK-15 and Peneroplis pertusus (Forskal), P. planatus (Fichtel and Moll), Sorites orbiculus Ehrenberg, Coscinospira hemprichii Ehrenberg in borehole HK-17 between 6.45 and 6 m. The large abundance of Peneroplis pertusus (Forskal) is noteable. This situation proves the presence of unusual conditions at the north of Golden Horn, probably suggesting a thermal water movement associated with fault activity. The other evidence supporting to this opinion is the presence of ostracoda, obtained from basal part of HK-17-HK-18 drilling sites, as Leptocythere sp., Callistocythre adriatica Masoli, Falunia sp., Aurila sp., Buntonia sp., Loxoconcha agilis Ruggieri, Xestoleberis dispar G. W. Müller which are mainly related to the Mediterranean bioprovence.