Radiolarian evidence of late cenozoic oceanic paleotemperatures,Ross sea,Antarctica

Radiolarian and paleomagnetic studies of 59 Antarctic piston cores reveal that since the middle Gauss ($\text{t ? 3}\text{m.y.}$) radiolarian faunas from the southern Ross Sea consistently have lacked certain species commonly found just to the north in the Southern Ocean. Common Antarctic species generally absent from southern Ross Sea sediments include: Spongopyle osculosus, Cenosphaera nagatai, Chromyechinus antarctica, Stylatractus neptumus, Diploplegma banzare, Prunopyle titan, and Desmospyris spongiosa. These species appear to have consistently preferred water slightly warmer than that of the southern Ross Sea. Their occurrence at intervals in cores from the northern Ross Sea and from north of the Ross Sea has been used as a quantitative paleoclimatic indicator. The resulting paleoclimatic curves reveal that the early Gauss was warmer than the late Gauss, the Matuyama and the Brunhes. Warm and cold periods during the Matuyama and the Brunhes appear to be of equal amplitude. Temperatures in the region since the early Gauss were never warmer by more than about 3°C than they are today. Radiolarian abundance and diversity appear to have been controlled primarily by changes in factors affecting their production.