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

IODP第317号考察队在新西兰南岛东缘的坎特伯雷盆地钻探了一个陆棚斜坡系统。七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。 根据底栖有孔虫的氧同位素分析，结合生物地层学，建立了一条氧同位素曲线和一条深度-年龄曲线。通过对介形虫化石组合的分析，结合沉降和沉积速率，重建了冰期和间冰期之间的海平面振幅。 中更新世过渡之后的层序边界对应于这一时期（MIS 22、16、12、8和6）出现的最高幅度氧同位素正偏移，相应的层序持续时间约为0.2百万年。我们估计，海平面升降幅度约50米，从1.8至1.26 Ma和超过100米，从0.9 Ma到现在。

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.