氡气测量在川藏铁路板块结合带构造活动研究中的应用  

MICRO-DOSE RADON MEASUREMENT FOR NEO-TECTONIC ACTIVITY AT PLATE COLLISION ZONES ALONG SICHUAN-TIBET RAILWAY

作　　者：黄超[1] 李渝生[1] 刘凯[1] 易树健 HUANG Chao;LI Yusheng;LIU Kai;YI Shujian(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059)

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059

出　　处：《工程地质学报》2018年第4期1025-1034,共10页Journal of Engineering Geology

基　　金：中国铁路总公司科技研究开发计划重大课题--川藏铁路修建关键技术研究(2014G004)资助

摘　　要：川藏铁路高速交通廊道研究区地质构造环境较为脆弱,尤其是金沙江结合带、澜沧江结合带、怒江结合带、嘉黎断裂带及雅鲁藏布江结合带5条主要板块碰撞结合带,均表现出不同程度的构造活动,其构造活动严重制约着川藏铁路的建设。本文在深入研究其地质建造特征、地震、深部结构及活动特征等基础上,运用微剂量氡气测量的方法表征结合带的地球化学特征,采用不同于常规统计学方法获取背景值,并通过定义异常系数(峰值mmax/背景值m0)探讨其与结合带地质建造、深部特征、地震及构造活动的关系。研究结果表明:每条测氡曲线均存在一个5 min,10 min,15 min 3次测氡数据相差极小"特殊点",氡气背景值与地壳岩石建造有显著关系;峰值与结合带所处大地构造位置有关;氡气异常系数整体沿西南至东北方向依次降低,氡气异常系数与断裂带构造活动关系极为显著,其中异常系数与水平位移速度,滑动速率及地应力均具有良好的正相关关系,回归方程分别为:y=0.869x+0.1278、y=0.7318x+15.1052、y=4.2196x+7.5263 9,研究结果对川藏铁路板块结合带的构造活动研究及川藏铁路的建设具有重大意义。The geological structure environment of the Sichuan-Tibet railway study area is relatively fragile. There are especially 5 main plate collision zones including Jinshajiang combination zone,Lancangjiang combination zone,Nujiang combination zone,Jiali faults and Yarlung Zangbo River combination zone. They show different tectonic activities. Theirs tectonic activity seriously restricts the construction of Sichuan-Tibet railway. Based on the deep study of geologic characteristics,seismic,deep structure and activity characteristics,this paper uses the method of micro-dose radon measurement to characterize the geochemical characteristics of the collision zone,and obtains the background value through the conventional statistical method. We define the anomalous coefficient（ peak value mmax/background value m0）. We then study the relationship between the coefficient and other factors including geological structure,deep features,earthquake and tectonic activity. The results show that there is a ＂specialpoint＂in each profile of radon measurement. The difference among 5 min,10 min and 15 min radon measurement data is very small. The radon background value is significantly related to the crustal rock construction. The peak value is related to the geotectonic position of the collision zone. The anomalous coefficient of radon decreases from southwest to northeast,which is remarkably related to tectonic activity. The anomalous coefficient has a positive correlation with horizontal displacement velocity,sliding velocity and ground stress. The results are as follows： y =0. 869 x＋0. 1278,y = 0. 7318 x ＋ 15. 1052,y = 4. 2196 x ＋ 7. 52639. The research results have a great significance to the study of tectonic activity of Sichuan-Tibet railway plate collision zone and the construction of Sichuan-Tibet railway.

关 键 词：氡气测量 川藏铁路 板块结合带 构造活动 

分 类 号：P642.27[天文地球—工程地质学]