湖南芙蓉锡矿田Rb-Sr同位素年龄及其地质意义  

Rb-Sr Isotopic Ages of the Furong Tin Orefield in Hunan and Their Implications

作　　者：马丽艳[1] 路远发[1] 梅玉萍[1] 陈希清[1] 杨红梅[1] 

机构地区：[1]中国地质调查局宜昌地质矿产研究所,湖北宜昌443003

出　　处：《地球学报》2005年第B09期143-145,共3页Acta Geoscientica Sinica

基　　金：本文为中国地质调查局项目“金属矿床精确定年技术方法及地质应用研究”（编号：1212010560901）成果之一.

摘　　要：本文通过对湖南芙蓉矿田的似斑状黑云母二长花岗岩、黑云母二长花岗岩和含矿云英岩进行了全岩Rb-Sr同位素分析，获得等时线年龄分别为155±6Ma、141±6Ma和146±3Ma。前者表明了芙蓉花岗岩主体侵位时间为燕山早期的早-中侏罗世，而后二者表明了芙蓉花岗岩主体侵位后的又一次岩浆活动和成矿作用可能发生在晚侏罗世，该矿田是在构造环境可能为地壳由挤压剪切向拉张伸展转化的时期形成的，而与芙蓉花岗岩主体侵入的岩浆活动无直接的成生关系。Rb-Sr isotopic analysis of 23 samples was made for porphyroid biotite admellite, biotite admellite and tin-bearing greisen from the Furong orefield, Hunan Province. Three groups of isochron ages were obtained, i.e., 155 ± 6 Ma, 141 ± 6 Ma and 146 ± 3 Ma, respectively. Among these data, the first one indicates the main emplacement episode of Furong granite during Early- Middle Jurassic, and the last two show another magrnatic intrusion and mineralization period probably occurring in Late Jurassic. Based on these data, the authors hold that the tin orefield was tectonically formed during the crustal conversion from compression-shearing to extension, with no direct genetic relationship with the main intrusion episode of Furong granite.

关 键 词：等时线年龄 RB-SR同位素 芙蓉锡矿田 湖南 芙蓉矿田 Rb-Sr 锡矿田 同位素年龄 地质意义 二长花岗岩 

分 类 号：P618.44[天文地球—矿床学] P588.21[天文地球—地质学]