Middle Miocene to Quaternary diatom biostratigraphy of DSDP Site 90-594

A diatom biostratigraphy is presented for middle Miocene through Quaternary sediments recovered from the Chatham Rise east of New Zealand's South Island. The upper 590 m of the 639.5-m composite-section Site 594 represents approximately 16 m.y. and is characterized by moderately to very poorly preserved diatoms of antarctic to temperate affinity. Pliocene through Quaternary assemblages are poorly preserved and dominated by antarctic-subantarctic species which provide detailed biostratigraphic control. Recognized are 11 of 14 zones of the middle upper Miocene to Quaternary Neogene Southern Ocean diatom zonation (NSD 7-NSD 20) of Ciesielski (1983; this chapter). […]

本研究针对新西兰南岛东部查塔姆海丘（Chatham Rise）钻获的中中新世至第四纪沉积物，开展了硅藻生物地层学研究。594站位的639.5米复合地层剖面中，上部590米的沉积序列对应约1600万年，其硅藻化石保存程度从中等到极差，类群兼具南极与温带亲缘特征。上新世至第四纪的硅藻组合保存状况不佳，以南极-亚南极种类为主，该类群可提供高精度的生物地层标定依据。Ciesielski（1983；本章）所建立的中晚中新世至第四纪新近纪南大洋硅藻分带方案（NSD 7-NSD 20）共计14个分带，本次研究识别出其中11个。[...]