【作者】 王海霞；

【导师】 李铁刚；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋地质， 2011， 硕士

【摘要】 西太平洋暖池以年均28℃等温线为界，是全球海气交换最强烈的地区，也是许多重要水团、洋流的汇集地。大洋暖池的变化制约着亚洲、太平洋区域,甚至全球气候变化和某些重要自然灾害的形成，是气候异常的源地之一，揭示西太平洋暖池的变化规律对于了解全球气候变化具有重要意义。为了了解西太平洋暖池的古环境演化过程，本文选取了位于西太暖池核心区Ontong Java海台上的97322-4（00o01.7321′S，159o14.6625′E，水深：2362m）站位柱状样沉积物为材料，进行了浮游有孔虫G. ruber与N. dutertrei壳体δ18O、δ13C的地球化学分析和有孔虫群落组合特征的分析，并结合前人研究成果对比重建了360ka以来西太平洋暖池核心区的古环境演化过程，填补了该区域古海洋研究分辨率较低的空白。通过与LR04标准氧同位素曲线的对比发现97322-4孔氧同位素地层到达MIS10期，共出现了四个冰期-间冰期旋回，次表层水变化幅度明显高于表层水，这说明次表层水对于环境的变化更为敏感，表明西太平洋暖池核心区的环境变化更多的发生在次表层水之中，即暖池的内部。97322-4孔在四个冰消期时均出现了浮游有孔虫壳体δ¹³C低值事件，可能反应了亚南极模态水（SAMW）和南极中层水（AAIW）对于低纬热带海区的影响，这一事件也为冰消期δ13C低值事件在热带太平洋地区存在的普遍性提供了新的证据，同时也进一步证明了南极高纬地区对低纬热带海区的影响。次表层种N. dutertrei壳体的δ13C值、底栖有孔虫丰度与U+B相对百分含量变化定性的反映了97322-4孔的古生产力变化过程，指示出研究区的古生产力存在冰期高，间冰期低的变化趋势，其驱动机制可能受控于温跃层深度类ENSO式的变动。97322-4孔的上层水体结构变化，并没有体现出明显的冰期-间冰期旋回特征，大致可以分为两个变化阶段：MIS10期～MIS7期，这一阶段温跃层整体呈变浅趋势；MIS7期以后，温跃层呈现出变深的趋势。97322-4孔浮游有孔虫组合表现出十分强烈的热带特征，热带-亚热带的代表属种在种群中占绝对的优势，97322-4孔浮游有孔虫群落组合的波动比较频繁，但是并没有严格的遵循冰期-间冰期旋回交替的规律。岁差和半岁差周期存在较普遍，说明该区的有孔虫丰度变动存在着明显的热带驱动。高纬驱动的斜率和偏心率周期也有体现，说明高纬驱动对该区也有影响作用。更多还原

【Abstract】 Western Pacific Warm Pool, an average 28℃isotherm as the boundary, is theregion of the world’s most intense air-sea exchange, but also is the gathering place ofmany important water masses and ocean currents. Changes in the WPWP influencethe climate change of Asia, Pacific and even global and the formation of someimportant natural disasters. It is one of the sources of climate anomalies. Revealingthe variation rule of the WPWP is very significant to understanding the global climatechange. In order to understand the paleoenviroment evolution of the WPWP, weselected in the core 97322-4 （00 o 01.7321 ’S, 159 o 14.6625’ E, water depth: 2362m）located in Ontong Java platform in the core of the WPWP as the researching materialsto analyse theδ18O,δ13C of planktonic foraminifera G. ruber and N. dutertrei and theforaminiferal assemblages and compare with the results of previous studies. Finally,we rebuilt the paleoenvironmental evolution course of the WPWP since 360ka andfilled the gaps of lower research resolution in this area.By oxygen isotope analysis, 97322-4 reached MIS10 period, with fourglacial-interglacial cycles. That the rate of change in sub-surface water wassignificantly higher than the surface water indicated that the subsurface water is moresensitive to changes in the environment and water temperature changes is more severe,which suggested that the WPWP environmental changes mostly occurred in thesub-surface water. Planktonic foraminiferalδ¹³C minimum events in fourdeglaciation may reflect the impact of the Subantarctic Mode Water （SAMW） andAntarctic Intermediate Water （AAIW） on the low-latitude tropical sea. This event proved the 13C minimum events in deglaciation is universal in the tropical Pacific, but also provided further evidence for the Antarctic influence to the tropics.Subsurface water’s carbon isotope , benthic foraminiferal abundance, U + B（%）qualitatively reflected the paleoproductivity change process of the hole 97322-4, which indicating that the glacial has high productivity and the interglacial has the low productivity. Its driving mechanism may be controlled by the ENSO-like alteration of the thermocline depth.The structure of upper water in 97322-4 didn’t present the glacial-interglacial cycle characteristics. Changes can be divided into two stages: MIS10-MIS7, in this phase the thermocline was shallower; after MIS7, the thermocline showing a deeper trend.The fluctuations of planktonic community composition in 97322-4 hole were more frequent, but did not strictly follow the glacial - interglacial cycles. Precession and semiprecession cycle were more common, indicating that the abundance of foraminifera in the area were influenced by the tropical driving. The slope and the eccentricity cycles are also reflected in the area, suggesting that the high latitudes also played the role of driver.更多还原