Latest Miocene to Late Pliocene Dinoflagellate Cyst Biostratigraphy of the Ocean Drilling Program Hole 642B on the Vøring Plateau
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An updated Late Neogene dinoflagellate cyst biozonation of the Norwegian Sea is needed, as it, together with other recent zonations from the Iceland Sea, the eastern North Atlantic and the eastern North Sea (Denmark), will form a cornerstone for achieving a better age constraint of the Utsira Formation. In the present study magnetostratigraphically dated palynological samples from the Ocean Drilling Program Hole 642B, on the outer Vøring Plateau, eastern Norwegian Sea, have been studied, and a contribution to an up to date Late Neogene biozonation is made. The studied interval encompasses the Late Messinian to the Early Piazencian, and has been divided into a local zonation scheme of four interval zones (KMB-1-KMB-4). The KMB-1 Interval Zone (>5.82-5.33 Ma) is defined by the highest persistent occurrence of Selenopemphix brevispinosa. The base is presently not defined. The KMB-2 Interval Zone (4.91-4.64 Ma) is defined from the highest persistent occurrence of Selenopemphix brevispinosa to the highest occurrence of Reticulatosphaera actinocoronata. The KMB-3 Interval Zone (4.50-3.60 Ma) is defined from the highest occurrence of Reticulatosphaera actinocoronata to the highest occurrence of Operculodinium? eirikianum var. crebrum. The KMB-4 Interval Zone is defined from the highest occurrence of Operculodinium? eirikianum var. crebrum, but the top is presently not defined. Within the KMB-1-KMB-3 interval zones, several dinoflagellate cyst and acritarch events have also been described. These zones and events were compared with the zonations from the Iceland Sea, the eastern North Atlantic and the eastern North Sea (Denmark). In general, this comparison revealed differences in the distribution and range of the dinoflagellate cysts and acritarchs, likely due to different latitudinal and oceanographic settings of the investigated locations. However, one good regional event and upper zone boundary, are clearly recognized in both the Icelandic Sea and the Norwegian Sea.
PublisherThe University of Bergen
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