Foraminiferal Assemblages at Ross Ice Shelf Project (RISP) Site J-9, Ross Sea, Antarctica

This dataset contains Miocene and Holocene foraminiferal population counts from the Ross Sea, Antarctica. In 1977–1978 and 1978–1979, the Ross Ice Shelf Project (RISP) recovered sediments from beneath the largest ice shelf in Antarctica at Site J-9 (82° S, 168° W), ~450 km from open marine waters at the calving front of the Ross Ice Shelf and ~890 km from the South Pole, one of the southernmost sites for marine sediment recovery in Antarctica. The samples are divided into a thin, unconsolidated upper unit (up to 20 cm thick) and a texturally similar but compacted lower unit (> 1m thick) containing reworked early, middle, and late Miocene diatom and calcareous benthic foraminiferal assemblages. A probable post-Last Glacial Maximum (LGM) disconformity separates the upper unit containing a dominantly agglutinated foraminiferal assemblage, from the lower unit consisting mostly of reworked Miocene calcareous benthic species. Three different sample types are noted: SC = sphincter core samples, CC = Core Catcher samples, int = interval samples. Species that are age diagnostic are noted in the species list and support a late Miocene age for the lower unit. All foraminifera were collected from the greater than 63 µm size fraction, in which the full floated material was examined.

本数据集收录了南极罗斯海的中新世（Miocene）与全新世（Holocene）有孔虫（foraminifera）种群计数数据。1977–1978年及1978–1979年期间，罗斯冰架项目（Ross Ice Shelf Project, RISP）在南极最大冰架下方的J-9站位（南纬82°，西经168°）获取了沉积物岩芯；该站位距离罗斯冰架崩解前沿的开阔海域约450千米，距南极点约890千米，是南极海洋沉积物钻探最靠南的站位之一。沉积物样品可分为两层：一层为薄而未固结的上层（厚度可达20厘米），另一层为结构与上层相似但已压实的下层（厚度大于1米），其中包含经再沉积的早、中、晚中新世硅藻与钙质底栖有孔虫组合。一处疑似末次冰盛期（Last Glacial Maximum, LGM）后的沉积间断面，将以粘结型有孔虫组合为主的上层，与以再沉积中新世钙质底栖物种为主的下层相互分隔。本次研究共记录三种样品类型：SC为括约肌岩芯样品（sphincter core samples），CC为岩芯抓斗样品（Core Catcher samples），int为间隔样品（interval samples）。物种列表中标注了具有年代指示意义的物种，这些物种佐证了下层沉积物的晚中新世年代归属。所有有孔虫均取自粒径大于63微米的粒级组分，且对该粒级的全部浮选物质完成了镜检分析。