(Table 5) Age determination of Tasman Sea transect samples@en

Quantitative analyses of planktonic foraminifera from 47 core-top samples (spatially distributed through the Tasman Sea) and cores RC12-113, E36-23, DSDP Sites 588, 592, 593, and ODP Site 828A (from a N-S transect), supplemented with stable-isotope analyses indicate that three planktonic foraminiferal assemblages (defined by factor analysis on core-top material) correlated with three hydrographic modes defined on the basis of, sea-surface temperatures, temperature profiles, seasonal changes in temperature and mixed-layer depth. Similar assemblages were found in down-core material along the Tasman Sea transect that, combined with semi-quantitative analyses of foraminiferal assemblages (provinces), and the coiling ratio of Globorotalia truncatulinoides, allows reconstruction of the position of the Tasman Front (or the Subtropical Divergence) during the late Brunhes Chron. The results indicate that the Tasman Front migrated from its present position at ~30°S to ~26°S during the last glacial maximum. The northward migration of the Tasman Front may indicate a reduction in volume of the equatorial warm-pool and/or an increase in the strength of cool subtropical water masses. The late Pleistocene distribution of G. truncatulinoides left-coiling from appears to be related to the formation of Subantarctic Mode Water thermostads. This relationship may explain the evolutionary origin of this species in the Southwest Pacific at 2.4 Ma simultaneously with the onset of late Pliocene glaciations. The past position of the Subtropical Convergence is reconstructed by means of coilingv directions in Neogloboquadrina pachyderma. The convergence apparently migrated slightly north of 43°S (core E36-23) during glacial stages 6, 10, and 12.对分布于塔斯曼海（Tasman Sea）的47个表层岩心样品，以及RC12-113、E36-23、深海钻探计划（Deep Sea Drilling Project, DSDP）588、592、593站位与大洋钻探计划（Ocean Drilling Program, ODP）828A站位（沿南北向断面）的岩心样品开展的浮游有孔虫（planktonic foraminifera）定量分析，结合稳定同位素分析结果显示：基于表层岩心样品因子分析定义的3种浮游有孔虫组合，与依据海表温度、温度剖面、温度季节变化及混合层深度划定的3种水团模式具有相关性。沿塔斯曼海断面的岩心深部样品中发现了类似的有孔虫组合，结合有孔虫组合（分区）的半定量分析结果与截圆抱球虫（Globorotalia truncatulinoides）的旋向比例，可重建布容正向极性时（Brunhes Chron）晚期塔斯曼海锋（Tasman Front，或称副热带辐散区（Subtropical Divergence））的位置。研究结果表明，末次冰盛期（last glacial maximum）期间塔斯曼海锋曾从当前约30°S的位置向北迁移至约26°S。塔斯曼海锋的北移可能指示赤道暖池（equatorial warm-pool）体积缩减，或是亚热带冷水团（cool subtropical water masses）强度增强，或二者兼具。左旋壳截圆抱球虫的晚更新世分布似乎与亚南极模态水（Subantarctic Mode Water）的恒温层（thermostads）形成相关，该关联或可解释该物种于2.4 Ma在西南太平洋的演化起源，这一时间恰好与上新世晚期冰川作用的启动同步。借助厚壳新抱球虫（Neogloboquadrina pachyderma）的旋向，可重建副热带辐合带（Subtropical Convergence）的古位置。在冰川期6、10与12阶段，该辐合带曾轻微北迁至43°S以北海域（E36-23岩心站位处）。