RESPONSE OF SURFACE-WATER MASSES AND CIRCULATION TO LATE QUATERNARY CLIMATE-CHANGE EAST OF NEW-ZEALAND

A series of cores from east of New Zealand have been examined to deter mine the Daleoceanographic history of the late Quaternary in the SW Pa cific using planktonic foraminiferal data. Distinct shifts of species carl be seen between glacial and interglacial times especially south o f Chatham Rise east of South Island. Foraminiferal fragmentation ratio s and benthic/planktonic foraminiferal ratios both show increased diss olution during glacials, especially isotope stage 2 to the south of Ch atham Rise. The present-day Subtropical Convergence appears to be tied to the Chatham Rise at 44 degrees S, but during glacial times this ri se separated cold water to the south from much warmer water to the nor th, with an associated strong thermal gradient across the rise; We est imate that this gradient could have presented as much as an 8 degrees C temperature change across 4 degrees of latitude during the maximum o f the last ice age, There is only weak evidence of the: Younger Dryas cool event, but there is a clear climatic optimum between 8 and 6.4 ka with temperatures 1 degrees-2 degrees C higher than the present day. The marine changes compare well with vegetational changes on both Sout h and North Island.