Figure 13. Overall diatom abundance vs. depth at Hole 1084A. Shipboard measurements of polarity and lithographic units are given on the right-hand side. The time interval of subantarctic influence in the late Pliocene is exemplified by the presence of Proboscia barboi (diatom) and Cycladophora pliocenica and by the sparse occurrence of Discoaster nannofossil species. We believe that a strong coastal upwelling system dominated over Site 1084 in the Pleistocene, whereas strong frontal systems (among the BCC, the up-welling filaments, and the BOC) dominated the late Pliocene, as exemplified by Chaetoceros resting spores and Thalassiothrix-rich sediments, respectively.

Figure 13. Overall diatom abundance vs. depth at Hole 1084A. Shipboard measurements of polarity and lithographic units are given on the right-hand side. The time interval of subantarctic influence in the late Pliocene is exemplified by the presence of Proboscia barboi (diatom) and Cycladophora pliocenica and by the sparse occurrence of Discoaster nannofossil species. We believe that a strong coastal upwelling system dominated over Site 1084 in the Pleistocene, whereas strong frontal systems (among the BCC, the up-welling filaments, and the BOC) dominated the late Pliocene, as exemplified by Chaetoceros resting spores and Thalassiothrix-rich sediments, respectively.