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Johnson, D.A., Schneider, D.A., Nigrini, C.A., Canlet, J.P. and Kent, D.V., 1989. Pliocene-Pleistocene radiolarien events and magnetostratigraphic calibrations for the tropical Indian Ocean. Micropaleontol., 14: 33-64.A composite of four piston cores from the Central Indian Basin and adjacent Ninetyeast Ridge has yielded a continuous magnetobiostratigraphic reference section for most of the Pliocene and the Pleistocene (0.0-4.5 Ma). We identified thirty-three radiolarian events (first-or last-occurrences), and precisely correlated each event to the Neogene geomagnetic polarity time scale. Thirteen of these events are based on revised taxonomic studies of the genera Anthocyrtidium and Pterocorys. Some events show significant departures from synchroneity: five of the radiolarian first-appearances and seven of the last-appearances are time-transgressive by 0.4 m.y. or greater. We here propose a revised, eleven-fold radiolarian zonation for the Pliocene-Pleistocene, using zonal boundaries defined by events which are easily recognized and are demonstrably synchronous in the tropical Indo-Paciflc. The sequence of faunal and floral events reported in this paper will allow high-resolution biostratigraphic correlations within the tropical Indian Ocean; however, the same sequence of events is not necessarily applicable to other tropical or extratropical regions.Pleistocene. We suggest discarding the Spongaster lineage as a criterion for defining zonal boundaries due to its demonstrable non-synchroneity and the scarcity of specimens of this genus in Indian Ocean cores. We propose an alternative zonation based upon several Pliocene radiolarian events which are more sharply defined in the Indian Ocean.

This paper summarizes the biostratigraphy and magnetostratigraphy of the 11 sites drilled on the Kerguelen Plateau and in Prydz Bay, Antarctica, during ODP Leg 119. Excellent magnetobiochronologic reference sections were obtained at deep-water Sites 745 and 746 (0-10 Ma) and at intermediate depth Site 744 (0-39 Ma) on the southern Kerguelen Plateau. Site 738, an intermediate depth companion site for Site 744, contains a nearly complete lowermost Oligocene to Turonian carbonate section including a continuous sequence across the Cretaceous/Tertiary boundary. Northern Kerguelen Sites 736 and 737 (ca. 600 m water depth) constitute a composite middle Eocene to Quaternary reference section near the present-day Antarctic Polar Front. Biostratigraphic control is limited in Prydz Bay Sites 739-743. Glacial sequences cored on the continental shelf at Sites 739 and 742 appear to form a composite record, possibly from the uppermost middle Eocene to the Quaternary; the entire upper Oligocene and most of the Miocene, however, are removed at an unconformity. Preglacial sediments at Site 741 contain Early Cretaceous pollen and spores, but the red beds cored at Site 740 are unfossiliferous. Poorly-fossiliferous glacial sediments of probable Quaternary age were sampled on the upper slope at Site 743. A magnetobiochronologic time scale is presented for the Late Cretaceous and Cenozoic of the Southern Ocean based on previous studies and the results of Leg 119 studies.

Abstract. -The examination of radiolarian biodiversity at the family level through Phanerozoic time reveals some general trends known in other groups of organisms, especially among plankton, while some other trends seem to be quite peculiar. The Permian /Triassic crisis that is one of the most important in the evolution of marine organisms, is marked in radiolarian assemblages by the extinction of two orders (Albaillellaria and Latentifistularia) towards the end of the Permian, and mostly by the tremendous diversification of Spumellaria and Nassellaria in the early-mid Triassic. Radiolarian diversity increased from Cambrian to Jurassic, remained quite stable during the Cretaceous and has decreased slightly since then. Diversité des familles de radiolaires au cours du tempsMots clés. -Radiolaires, Famille, Diversité, Paléozoïque, Mésozoïque, Cénozoïque, Extinction, Radiation, Protoctistes.Résumé. -L'examen de la biodiversité des radiolaires, au niveau de la famille au cours du Phanérozoïque révèle quelques tendances générales connues chez d'autres groupes d'organismes, surtout dans le plancton, alors que d'autres tendances leur sont particulières. La crise permo-triasique, l'une des plus importantes dans l'évolution des organismes marins, est marquée chez les radiolaires par l'extinction de deux familles (Albaillellaria et Latentifistularia) vers la fin du Permien, mais surtout par une énorme diversification des spumellaires et nassellaires au Trias inférieur et moyen. La diversité des radiolaires s'accroît du Cambrien au Jurassique, reste relativement stable au Crétacé et décroît légèrement depuis.

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