中文摘要：

捅要：对珠江三角洲PRDl6孑L的微体动物群进行了分析，共发现底栖有孔虫12属24种，介形类9属13种，它们可分别划分为3种生态类型。根据有孔虫和介形类微体动物群的分布特征、并结合岩性和沉积粒度特征，推断PRDl6孔研究区晚更新世以来沉积环境演化经历了5个阶段：①34600calaBP以前为河流相环境，形成了研究区最早的第四纪河床相砂砾沉积；②34600～23900colaBP推测为河口湾环境；③23900—7960colaBP受末次盛冰期影响，研究区暴露地表遭受风化剥蚀，形成花斑黏土；④7960—2810calaBP为全新世大海侵时期，研究区为河口海湾环境，发育以广盐性有孔虫和中盐一多盐性介形类为主的微体动物群，其间发生了2次小规模海平面波动，受地块区域沉降作用影响，研究区在3873calaBP左右水深达到最大，主要有孔虫和介形类属种的丰度达到全新世最高值；⑤2810calaBP以来海平面持续下降，研究区由潮坪环境变为河121砂坝，随后河流作用增强，又逐渐变为河流冲积～潮上带环境。关键词：珠江三角洲；有孔虫；介形类；晚第四纪；古环境中图分类号：P534．63文献标志码：A文章编号：0529—6579（2013）03—0128—06

英文摘要：

Microfaunas of borehole PRD16 in the Pearl River Delta have been quantitatively analyzed in this paper. A total of 24 benthic foraminifera species referred to 12 genera and 13 ostracod species referred to 9 genera were found in the borehole. They can be divided into 3 ecological groups. The microfaunal analytical results, combined with lithological and sedimentary grain characteristics, suggest that the study area experienced environmental changes since the Late Pleistocene. A riverine environment be- gan to develop before 34 600 cal a BP. Between 34 600 and 23 900 cal a BP, the environment generally changed to an estuarine condition. Between 23 900 and 7 960 ca1 a BP, the sediments experienced weathering and erosion, characterized by a layer of mottled clay. At around 7 960 cal a BP, sea level rose rapidly and an estuary environment with euryhaline foraminifera and brackish ostracod faunas existed until 2 810 cal a BP. Two second-order sea level fluctuations can be recognized based on the composition and abundance of microfaunas. The maximum water depth occurred at approximately 3 873 cal a BP, demonstrated by the highest abundance of foraminifera and ostracods in the borehole. Since 2 810 cal a BP, the environment gradually changed into a fluvial supratidal zone with increased influence of river processes.