Radiolarians from ODP Leg 119, Kerguelen Plateau

Radiolarians are abundant and well preserved in the Neogene of the Kerguelen Plateau. They are common and moderately to well preserved in the Oligocene sequences of Site 738, where the Eocene/Oligocene boundary was observed for the first time in subantarctic sediments, and Site 744. Radiolarians are absent from all glacial sediments from Prydz Bay.
Classical Neogene stratigraphic markers were tabulated at all sites. Correlations with paleomagnetic ages were made at Sites 745 and 746 for 26 Pliocene-Pleistocene radiolarian events. Many Miocene to Holocene species are missing from Sites 736 and 737, which were drilled in shallow water (less than 800 m). The missing species are considered to be deepliving forms.
Occurrences and relative abundances of morphotypes at six sites are reported. Two new genera (Eurystomoskevos and Cymaetron) and 17 new species (Actinomma kerguelenensis, A. campilacantha, Prunopyle trypopyrena, Stylodictya tainemplekta, Lithomelissa cheni, L. dupliphysa, Lophophaena(?) thaumasia, Pseudodictyophimus galeatus, Lamprocyclas inexpectata, L. prionotocodon, Botryostrobus kerguelensis, B. rednosus, Dictyoprora physothorax, Eucyrtidium antiquum, E.(?) mariae, Eurystomoskevos petrushevskaae, and Cymaetron sinolampas) are described from the middle Eocene to Oligocene sediments at Sites 738 and 744. Twenty-seven stratigraphic events are recorded in the middle to late Eocene of Site 738, and 27 additional stratigraphic datums are recorded, and correlated to paleomagnetic stratigraphy, in the early Oligocene at Sites 738 and 744. Eight radiolarian events are recorded in the late Oligocene at Site 744. New evolutionary lineages are proposed for Calocyclas semipolita and Prunopyle trypopyrena.

放射虫（Radiolarians）在凯尔盖朗高原的新近纪地层中分布丰富且保存完好。在738站位与744站位的渐新世地层中，放射虫亦较为常见，保存程度从中等到完好不等；其中738站位首次在亚南极沉积物中识别出始新世/渐新世界线。普里兹湾的所有冰川沉积物中均未发现放射虫。

所有站位均已汇总列示经典新近纪地层标志。针对745与746站位，已针对26个上新世-更新世放射虫事件建立了与古地磁年龄的对应关系。736与737站位为浅水环境（水深不足800米）钻探所得，缺失多数中新世至全新世的放射虫物种，上述缺失类群被归为深栖类群。

本文报道了6个站位中各放射虫形态类型的产出情况与相对丰度。在738与744站位的中始新世至渐新世沉积物中，发现并描述了2个新属（Eurystomoskevos与Cymaetron）及17个新种：Actinomma kerguelenensis、A. campilacantha、Prunopyle trypopyrena、Stylodictya tainemplekta、Lithomelissa cheni、L. dupliphysa、Lophophaena(?) thaumasia、Pseudodictyophimus galeatus、Lamprocyclas inexpectata、L. prionotocodon、Botryostrobus kerguelensis、B. rednosus、Dictyoprora physothorax、Eucyrtidium antiquum、E.(?) mariae、Eurystomoskevos petrushevskaae以及Cymaetron sinolampas。738站位的中晚始新世地层中共记录了27个地层事件；738与744站位的早渐新世地层中则额外记录了27个地层基准面，并将其与古地磁地层学进行了对比关联。744站位的晚渐新世地层中共记录了8个放射虫事件。为Calocyclas semipolita与Prunopyle trypopyrena提出了全新的演化谱系。