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Calcareous nannoplankton biostratigraphy has been worked out in the eastern Mediterranean using deep-sea sediments recovered from DSDP Leg 42A Sites 375 and 376. These two drill sites were located approximately 55 km west of Cyprus on the Florence Rise. Sediments, ranging in age from early Miocene (Helicosphaera ampliaperta Zone) through Holocene (Emiliania huxleyi zone), contain sufficient age-diagnostic species to recognize essentially all of the low-latitude nannoplankton
zones described by D. Bukry, although regional, secondary marker species are needed to define some zonal boundaries. Nannoplankton zonation established at these two deep-sea localities provides a standard of reference for much of the Neogene in the eastern Mediterranean.
Reworked Cretaceous and early Cenozoic nannoplankton are present throughout the stratigraphic interval studied, but not in quantities large enough to mask indigenous species which are used for the determination of zonal boundaries. Sedimentation rates at Sites 375 and 376 were highest in the late Miocene and late Pleistocene. Open-marine, warm-water species of discoasters are present in significant numbers throughout the Miocene and Pliocene. Earliest Pliocene assemblages contain numerous specimens of the deep-water genera Amaurolithus, Ceratolithus, and Triquetrorhabdulus, evidence of the rapid marine transgression immediately following Messinian evaporite deposition.
Nannoplankton in post-Messinian sediments at the drill sites and the Zanclean stratotype at Capo Rossello, Sicily, indicate that the base of the Amaurolithus tricorniculatus Zone (base of Triquetrorhabdulus rugosus Subzone) corresponds to the Miocene-Pliocene boundary.
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