Date of this Version
Fossil specimens of the exclusively oceanic calcareous nannoplankton were found only in the upper 200 m of the Cape Roberts Project 3 (CRP-3) cores. These assemblages are depauperate and sporadic in occurrence. The majority of the assemblages contain fewer than 4 species, indicating a severe palaeoecological restriction. The clear domination of these assemblages by reticulofenestrid species, coupled with the almost total exclusion of Coccolithus pelagicus, indicates cold surface water conditions in the Victoria Land Basin during the lives of these poor algae. These cold surface water conditions, perhaps coupled with abnormal surface water chemistry, excluded almost all of the age-diagnostic species from the area. The occurrence of Transversopontis pulcheroides, however, suggests a biostratigraphic assignment of lower Oligocene for this part of the core. The CRP-3 assemblages occur within fine-grained clastic sedimentary rocks, but only those that are in close stratigraphical proximity with coarser-grained lithologies.