广东三水芦苞-大塘地区古近纪早中期淡水生物群的发现及其地质意义

对研究区内地层进行了多重划分对比,将古近纪地层划分为莘庄村组、土布心组、宝月组和华涌组4个岩石地层单位,并在该地层中首次发现轮藻、介形虫、腹足类、双壳类、鱼类、植物6个门类7个化石组合25属60余种生物化石,填补了本区生物地层的空白。根据岩石地层层序、生物组合特征和7个动植物化石组合的国内外对比,确定其形成时代为古新世-始新世,形成环境为陆相淡水,气候干旱、炎热。喜马拉雅运动使本区抬升为陆地,进一步证实晚古新世海侵边界大致在南边镇-水锅尾-基塘连线之南东地带。

Discovery of Early-Middle Eogene fresh water biota and its geological significance in Lubao-Datang area, Sanshui, Guangdong Province

Multiple stratigraphical classification and correlation are carried out in Lubao-Datang area,Sanshui,Guangdong Province,and the Eogene strata are divided into the Xinzhuangcun Fm.,Buxin Fm.,Baoyun Fm.and Huayong Fm..Various fossils including charophyta,ostracoda,gasteropod,bivalve,fish and plant of more than 60 species and 25 genera have been found for the first time in the study area, which can be assorted to 7 fossil assemblages.Correlation of lithostratigraphical sequence and fossil assemblages shows that the biota was formed in continental facies fresh water environment during Paleocene-Eocene period in the condition of hot and arid climate.Himalayan orogeny made the area uplift to continent,confirming that the late-Paleocene coast line was probably at southeast Nanbianzhen-Shuiguowei-Jitang area.