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1 July 2017 Late Neogene Radiolarian Biostratigraphy of the Eastern North Pacific ODP Sites 1020/1021
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Abstract

During Ocean Drilling Program Leg 167, Sites 1020/1021 were drilled to assess the paleoceanographic conditions within the northern region of the California Current. Radiolarian records from the upper middle Miocene to Pleistocene were obtained at Sites 1020/1021 cores in order to develop a correlation between Neogene biostratigraphic data and paleomagnetic chronostratigraphy. Of 66 radiolarian events identified during this study, 26 Pleistocene to late Miocene events were directly tied to the paleomagnetic stratigraphy, and 40 middle to late Miocene events were correlated with that result by second-order methods based on the diatom biostratigraphy. The updated ages of radiolarian bioevents were estimated based on the geologic time scale of Ogg (2012). Of these events, 12 bioevents that define low-latitude tropical radiolarian zones were either missing at Sites 1020/1021, or proved to have different ranges from those in the tropics. Using selected bioevents of the temperate and subarctic species, the studied sequences of Sites 1020/1021 were divided into fifteen radiolarian zones/subzones from the Eucyrtidium inflatum Zone to Botryostrobus aquilonaris Zone. Six new subzones were described: Hexacontium parviakitaense, Lamprocyclas hannai, Lithelius klingi, Dictyophimus splendens, Cycladophora cabrilloensis, and Collosphaera reynoldsi subzones. The Cycladophora funakawai Zone was proposed for the subarctic Northwest Pacific.

© by the Palaeontological Society of Japan
Shin-Ichi Kamikuri "Late Neogene Radiolarian Biostratigraphy of the Eastern North Pacific ODP Sites 1020/1021," Paleontological Research 21(3), 230-254, (1 July 2017). https://doi.org/10.2517/2016PR027
Received: 13 September 2015; Accepted: 1 September 2016; Published: 1 July 2017
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