^(40)Ar(^(40)Ar^(*)+^(40)Ar_(E))、^(39)Ar释气特征与过剩氩的甄别及年代学意义  

THE RELEASE OF ^(40)Ar(^(40)Ar^(*)+^(40)Ar_(E) AND ^(39)Ar IN ^(40)Ar/^(39)Ar SAMPLES AND ITS CHRONOLOGICALSIGNIFICANCE

作　　者：李正华[1] 戴 谟 邱华宁[1] 

机构地区：[1]中国科学院地球化学研究所

出　　处：《地质科学》1995年第1期40-46,共7页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金资助

摘　　要：对具有不同地质历史背景的３类４０Ａｒ／３９Ａｒ法样品中的４０Ａｒ和３９Ａｒ释出特征进行对比，研究结果表明，４０Ａｒ／３９Ａｒ法样品中的４０Ａｒ、３９Ａｒ释气曲线主要表现为以下３种形式：完全重合型、过剩氩型和不规则型。当４０Ａｒ与３９Ａｒ释气曲线呈完全重合型时，４０Ａｒ／３９Ａｒ法全熔年龄代表了岩体的形成年龄；当４０Ａｒ、３９Ａｒ释气曲线是过剩氩型时，４０Ａｒ／３９Ａｒ法全熔年龄则大于岩体的形成年龄；当４０Ａｒ与３９Ａｒ释气曲线呈不规则型时，表明样品中的放射成固氩（４０Ａｒ）发生了丢失，其全熔年龄一般较岩体的形成年龄小。对于４０Ａｒ、３９Ａｒ释气曲线呈过剩氩型的样品，４０Ａｒ／３９Ａｒ法年龄谱通常呈马鞍形，且马鞍形年龄谱的底部年龄一般都具有地质意义，代表了岩体的形成年龄。对于４０Ａｒ、３９Ａｒ释气曲线呈不规则型的样品，对其年龄谱的解释应持谨慎态度。A suit of 40Ar/39Ar samples have been studied on the release of 40Ar(40Ar+ 40ArE) and 39Ar and show three patterns of curve of 4oAr and 39Ar released. The samples without excess 4oAr which have a sample geological history show a similar trend of 'oAr to s,Ar released. The samples which have undergone a complex history show a different trend of 'oAr and 39Ar release. A typical pattern of the behavior of 40Ar and 39Ar released from 40Ar/39Ar samples which have excess 40Ar is presented in this paper. The mechanism has been discussed in the text.

关 键 词：^(40)Ar/^(39)Ar法 过剩氩 释气曲线 扩散 

分 类 号：P597.3[天文地球—地球化学] O613.13[天文地球—地质学]