广州地区晚第四纪孢粉气候研究

Late Quaternary Pollen Records and Climate Significance in Guangzhou

利用广州地区南北2个不同沉积地貌区的钻孔进行孢粉分析,结合测年和沉积信息,分析了广州所代表的珠江三角洲地区晚更新世以来的沉积环境和气候变化。孢粉分析结果显示:在晚更新世珠江三角洲地区气候经历了偏冷干-偏凉干-暖湿-热湿-偏凉干-冷干的变化过程,末次冰期对本区具有明显影响,使全新世和晚更新世孢粉组合表现出一定的差异;全新世气候明显转暖湿,整体上以暖湿为主,但出现了一些小的气候波动事件,最明显的是在2 250 a BP前后偏凉干的变化;该区在晚更新世和全新世各经历过一次海侵,两孔反映的气候期和海平面变化较为一致,气候和海平面变化也有很好的对应。两孔在地层、沉积相和孢粉特征上的差异是地理位置、沉积环境和基座地貌等差异造成的。

Through the pollen analysis,combined with the informations on dating and sedimentation of two drilling cores located at different deposition-geomorphological area in the northern and southern part of Guangzhou,the deposition environmental and climatic changes since the late Pleistocene in Guangzhou,the Pearl River Delta,are suggested.Pollen records show that the climate during the late Pleistocene changed as below： partially dry-cold,slightly cool-dry,warm-humid,hot-moisture below,partially cool-dry,cold-dry.The obvious influence from the Last Maximum Glaciation resulted in the difference of pollen assemblage characteristics between the Holocene and the late Pleistocene.The climate became generally warm and humid in the Holocene,but being alterated with some minor climatic fluctuation events,e.g.the most obvious partial dry-cool transition around 2250a BP.Two transgressions have affected the delta during the late Pleistocene and the Holocene.Not only the variations of climatic and sea-level changes of two cores are consistent each other,but also a good correspondence between climate and sea-level change is shown.The differences on stratigraphy,sedimentary facies and pollen characteristics of two cores were resulted from the distinctive location,sedimentary environment and the topography of depositional bed.