Late Neogene agglutinated foraminifera from the central Arctic Ocean

• Main Author: Evans, John Rhys
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UCL (University College London) 1997
• Subjects: Earth sciences; Arctic ocean; Neogene; Arctic; Arctic Ocean; Breaker; Polar Star; Foraminifera*
• Online Access: https://discovery.ucl.ac.uk/id/eprint/10101704/1/out.pdf; https://discovery.ucl.ac.uk/id/eprint/10101704/

In the first detailed study of its kind Late Neogene (Pliocene-Pleistocene) deep water agglutinated foraminifera (DWAF) from central Arctic Ocean sediments are presented, analysed and interpreted. Four sedimentary cores {Cores PS2177-5, PS2200-5, PS2212-3, PS2185-6} collected by the RV Polarstern during the German cruise (ARKVIII/3) to the Eurasian Basin are examined in this study. Another four sedimentary cores {PI-92-AR 39; PI-92-AR 30, PI-92-AR 27, PI- 93-AR 21} were studied, collected by the United States Coastguard Ice breaker Polar Star in the north west (Amerasian) region of the Arctic Ocean. The main species found are Cyclammina pusilla, dominating all cores except PS2212-3; Alveolophragmium polarensis, Trochammina lomonosovensis new species, Glomospira gordialis, G. charoides, Psammosphaera fusca and Cystammina pauciloculata. The DWAF abundance correlates with interglacial/glacial cycles, which is linked with the reduction of ice cover in interglacial periods, leading to increased surface productivity and an increase of organic flux and nutrients to the sea floor. The DWAF lived epifaunally in bathyal, food limited environments. Productivity in both basins was found to be similar. Abundance data is slightly higher in the Amerasian Basin. DWAF abundance can be used as a proxy to study Plio-Pleistocene palaeoenvironment, palaeoceanography and palaeoproductivity in the Arctic Ocean. Stratigraphic models from previous studies are re-evaluated. The oldest Eurasian Basin core ranges from the Gilbert Chron (Core PS2185-6, 4.9 Ma. at base) to the top of the Brunhes Chron. The youngest, Core PS2212-3 ranges from oxygen isotope Stage 6-1. The two youngest Amerasian cores, PI-92-AR 30 and 27 correlate with the Matuyama and Brunhes Chronozone and the oldest cores, PI-92-AR 39 and PI-93-AR 21 range from the Gilbert to the top of the Brunhes Chron.