PALAEOCEANOGRAPHIC SIGNIFICANCE OF NEW AND REVISED PALEONTOLOGICAL DATINGS FOR THE ONSET OF VIGLA LIMESTONE SEDIMENTATION IN THE IONIAN ZONE OF GREECE

Radiolarian and calpionellid dating establish a significant sedimentar y hiatus within a reduced pelagic sequence of the central part of the Ionian zone (western Greece). Bottom-current activity probably decreas ed during the Oxfordian, allowing encroachment of radiolarian-rich sed iments onto a Jurassic high (at Kato Kouklessi), and then increased ag ain during Kimmeridgian-Tithonian time. The onset of Vigla Limestone s edimentation is diachronous within the Ionian zone, spanning late Tith onian to various levels of early Berriasian time. This diachroneity ca n be explained by dispersal of fine-grained sediment by current activi ty.