张家口汉诺坝玄武岩K-Ar年龄计时  

K-Ar DATING OF HANNUABA BASALTS AT ZHANJIAKOU

作　　者：王慧芬[1] 戴橦谟[1] 范嗣昆[1] 杨学昌[1] 

机构地区：[1]中国科学院地球化学研究所

出　　处：《地球化学》1985年第3期206-215,共10页Geochimica

摘　　要：汉诺坝玄武岩分布在蒙古高原东南边缘，面积约18000km^2.分为东西两区：东区玄武岩处于赤峰-康保深断裂东部，主要分布于赤峰、围场以北；西区玄武岩出露在建平-承德-赤城深断裂西段，分布于张家口-大同西北。(图1)。The Hannuaba basalts are located in the area of the Mongolian Plateau. Research work on the basalts started in 1920's. Still no unanimous conclusion has been drawn on the age of emplacement.Samples were systematically collected from four representative sections in this re-gion. Whole-rook samples and some separated minerals, such as analbite and phlogopite were all collected from fresh unaltered or slightly altered basalts and determined by K-Ar method.The 38Ar isotopic dilution method was used to determine K-Ar ages of the samples on an MM-1200 mass-spectrometer. 20 apparent ages were obtained. After isochron-treated these ages fall into two groups: 24m.y. and 18 m.y., corresponding to Early Miocene and Middle Miocene, respectively. The results are in good agreement with stra-tigraphic evidence.

关 键 词：汉诺坝玄武岩 钾-氩年龄 沉积岩 张家口 

分 类 号：P588.145[天文地球—岩石学] P597.3[天文地球—地质学]