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为了探索和揭示2.5MaBP前后东亚季风演变历史及植被演替对气候演化的响应,对南海南部大洋钻探ODP1143站(9°22’N、113°17’E)深海柱状样的上部135～95m(3.0～2.0MaBP)共146个孢粉样品进行了分析研究,时间分辨率为7ka/样,孢粉谱显示沉积率变化显著,以2.6MaBP为界可明显分为两个阶段,与前一阶段3.0～2.6MaBP相比,2.6～2.0MaBP时段各类型花粉及孢子沉积率均有显著提高。该结果表明2.6MaBP南海海平面有显著下降,可与北半球冰盖形成、东亚季风增强相对应。2.6MaBP以后,各类型孢粉沉积率高低变化揭示南海海平面有多次上升和下降,代表了多次冰期-间冰期旋回。该结果与深海氧同位素分期相对应。频谱分析表明3.0～2.0MaBP存在0.1Ma(偏心率)和46.9ka(斜率)的周期。
In order to explore and reveal the evolution history of the East Asian monsoon before and after 2.5 Ma BP and the response of vegetation succession to the climate evolution, the upper part of the deep-sea column ODP1143 station (9 ° 22’N, 113 ° 17’E) in the southern South China Sea was drilled at 135 ~ 95m 3.0 ~ 2.0MaBP). A total of 146 sporopollen samples were analyzed with a temporal resolution of 7 kA / sample. The spore-pollen spectra showed significant changes in sedimentation rate. The 2.6MaBP boundary was clearly divided into two stages, 3.0 ~ 2.6MaBP compared to 2.6 ~ 2.0MaBP period of various types of pollen and spore deposition rates were significantly increased. The results show that the 2.6MaBP South China Sea has a significant decrease in sea level, which can be related to the formation of the northern hemisphere ice sheet and the increase of the East Asian monsoon. After 2.6MaBP, the changes of sedimentation rate of various types of sporopollen showed that the sea level of the South China Sea rose and fell many times, representing several cycles of glacial-interglacial cycles. This result corresponds to the deep-sea oxygen isotope staging. Spectral analysis showed that there was a period of 0.1 Ma (eccentricity) and 46.9 ka (slope) for 3.0-2.0 Ma BP.