Late Cenozoic sea level changes, their timing and amplitude in offshore New Zealand: Results from IODP Expedition 317

IODP 317考察队在新西兰南岛东部边缘的坎特伯雷盆地钻探了一个大陆架斜坡系统。7个主要的岩心不连续面对应于地震剖面上解释的更新世层序边界。通过对底栖有孔虫的同位素分析，结合生物地层学，得到了氧同位素曲线和深度年龄曲线。通过对介形虫化石组合的分析，考虑沉降速率和沉积速率，重建了冰期和间冰期之间的海平面振幅。中更新世转变后的层序边界对应于该时期（MIS 22、16、12、8和6）最大幅度的氧同位素正偏移，对应的层序持续时间为~0.2 m.y。我们估计在1.8 ~ 1.26 Ma期间上升幅度约为50 m，在0.9 Ma至今期间上升幅度超过100 m。

IODP Expedition 317 dilled a shelf-slope system in the Canterbury Basin on the eastern margin of the South Island of New Zealand. Seven major core discontinuities correspond to Pleistocene sequence boundaries interpreted on the seismic profiles. An Oxygen isotopic curve and a depth-age curve were generated based on isotopic analysis of benthic foraminifera coupled with biostratigraphy. Sea level amplitudes between glacial and interglacial stages were reconstructed by the analysis of fossil ostracode assemblage taking into consideration subsidence and sedimentation rates. The sequence boundaries that follow the mid-Pleistocene transition correspond to the highest-amplitude oxygen isotope positive excursions that occur during this period (MIS 22, 16, 12, 8 and 6) and the corresponding sequence durations are ~0.2 m.y.. We estimate that eustatic amplitudes were ~50 m from 1.8 to 1.26 Ma and exceed 100 m from 0.9 Ma to present.