摘要
根据火山岩样品的Rb Sr和Sm Nd同位素分析结果 ,得到北京西山沿河城地区的东岭台组的Rb Sr等时线年龄为 1 31 2Ma ,误差为± 1 2 3Ma ( 95%置信区间 ) ,或± 3 3Ma ( 1σ) ,M S W D 等于 1 4 0 ;很可能属于早白垩世Berri asian阶。北京西山大台 燕翅一带的髫髻山组火山岩受后期蚀变和变质作用的影响 ,其 1 4 6 1 4 8Ma的斜长石40 Ar 3
According to the Rb-Sr and Sm-Nd isotopic analysis of volcanic rock samples of the Donglingtai Formation in Xishan (Western Hills) of Beijing Municipality,the Rb-Sr isochron age of 131 2Ma with the error of±12 3Ma(95% confidence level) or±3 3Ma (1σ) (M S W D =140) was obtained.Therefore,it is very possible that Donglingtai Formation belongs to Berriasian Stage of Early Cretaceous Epoch.However,the 146-148Ma age of Tiaojishan volcanic rocks in Datai-Yanchi area of Xishan,which is obtained by plagioclase 40Ar- 36Ar method,maybe only represent its metamorphic age,due to the alteration and low-grade metamorphism suffered by Tiaojishan volcanic rocks in Xishan region.
出处
《北京地质》
2003年第4期6-12,共7页
Beijing Geology
基金
国家自然科学基金项目 (编号 4 0 10 4 0 0 3)
中国博士后科学基金
国土资源部国际合作与科技司科技发展计划"华南地区岩石圈三维结构及其演化" (2 0 0 0 10 10 2 0 6 )项目联合资助
