中文摘要：

应用Rb-Sr同位素体系对宁芜盆地娘娘山组火山岩进行年代学分析,样品的全岩—钾长石—斜长石—黑云母的Rb-Sr同位素比值拟合成良好的直线,矿物内部等时线年龄为133.1±3.2Ma（MSWD=0.096）,代表了娘娘山组火山岩的形成年龄,该年龄值与下伏的龙王山组、大王山组火山岩的形成年龄相近。年代学对比表明,庐枞盆地和宁芜盆地火山岩是集中在130Ma前后较短的时间范围内形成的,指示了长江中下游地区在130Ma左右可能处于拉张的峰期阶段。

英文摘要：

The volcanic rock from the Niangniangshan Formation in the Ningwu （Nanjing--Wuhu） volcanic basin is used for Rb-Sr isotopic dating. The Rb and Sr isotopic ratios of whole rock, K-feldspar, plagioclase and biotite form a good linearity in n（87Rb）/n（86Sr） vs. n（87Sr）/n（S6Sr） space. The isochron age of inner-minerals is 133.1 ~ 3.2 Ma （MSWD=0. 096）, which represents the formation age of the volcanic rocks from the Niangniangshan formation. This age is consistent in error with that of underlying volcanic rocks of the Longwangshan and the Dawangshan formations. Chronological comparisons indicate that the volcanic rocks from the Luzong （Lujiang--Zongyang） and Ningwu volcanic basins were formed during a short-term around 130 Ma, implying that the extension of the Lower Yangtze region might achieve its maximum at ca 130 Ma.