Distribution of calcareous nannofossils in the lower sequence of the CIROS-1 sediment core (Table 2) ...

• Main Author: Wuchang Wei
• Format: Dataset
• Language: English
• Published: PANGAEA - Publishing Network for Geoscientific and Environmental Data 1992
• Subjects: Antarc*; Antarctica; McMurdo Sound; Ross Sea
• Online Access: https://dx.doi.org/10.15468/nys5rx; https://www.gbif.org/dataset/820aee92-f762-11e1-a439-00145eb45e9a

Semiquantitative data of calcareous nannofossil species abundance were collected for 31 samples from 380.00 to 696.61 m below sea floor (mbsf) in the CIROS-1 core from the western McMurdo Sound (Ross Sea). This core has provided the most complete record of Paleogene glacial history of Antarctica. Only half of the samples yielded calcareous nannofossils and species diversity is generally low. However, several samples contain diverse assemblages and nannofossil zonal markers. Isthmolithus recurvus was found between 406.57 and 681.16 mbsf. This species has an age range of ~35-39 Ma in the mid to high latitudes, as calibrated previously by magnetostratigraphy at a number of DSDP/ODP sites. The interval from 406.57 to 681.16 mbsf can be assigned to the late Eocene-earliest Oligocene (~35-39 Ma), and the sample at 391.85 mbsf, which still contains Reticulofenestra hillae and Reticulofenestra umbilica but does not contain I. recurvus, is identified as early Oligocene age (~33-34 Ma). This represents an age ...