摘要
滇西崇山岩群一直被认为是元古宙的大陆地壳-结晶基底,但至今无精确的年龄依据。对滇西澜沧江南段小湾地区崇山岩群的5件样品(糜棱岩化斜长变粒岩、黑云斜长角闪岩、片麻岩、糜棱岩化花岗质片麻岩、糜棱岩化黑云斜长变粒岩)进行锆石U-Pb定年。5件样品的锆石阴极发光图像显示,锆石有明显的生长振荡环带,指示岩浆成因。5件样品锆石的206Pb/238U年龄加权平均值分别为239.4±3.8Ma、248.4±4.3Ma、237.1±5.7Ma、268.7±3.2Ma、238.4±5.5Ma。根据野外地质特征和年龄数据,认为滇西澜沧江南段小湾地区崇山岩群是不同时代、不同岩性的岩体/地层(二叠系、三叠系)经后期变质作用形成的一套正变质岩,并不全是古老基底岩石出露。
This paper focuses on the LA-ICP_MS U-Pb ages of the zircons of five samples （mylonitization plagioclase leptynite , bio - tite amphibolites , gneiss , mylonitization granitic gneiss , and mylonitization biotite amphibolites^） from the Chongshan Xiaowan area along the southern section of Lancang River of western Yunnan. Cathodoluminescence images of five samples revea that these zircon cryst ls generaiy have oscillatory zoning, implying their magatic genesis. One hundred and two anayseples yielded concordance, wi th their weighted average ages being 239.4±3.8Ma, 248.4±4.3Ma, 237.1 ±5.7Ma, 268.7±3.2Ma,and 238.4±5.5Ma. According to geologca characteristics and avaiable age data , it is considered that the so-the Xiaowan area is ortho me tamo rhite composed of various parent components wi th different ages rather crystmine basement rocks as previously considered.
作者
徐云飞
刘军平
丛峰
孙柏东
黄晓明
XUYunfei;LIUjunping;CONGFeng;SUNBaidong;HUANGXiaoming(Facuity of Land and Resource,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;Yunnan Institute of Geological Survey,Kunming 60211,Yunnan,China;Chengdu Center of China Geological Survey,Chengdu 610081,Sichuun,China)
出处
《地质通报》
CAS
CSCD
北大核心
2018年第6期1006-1014,共9页
Geological Bulletin of China
基金
中国地质调查局项目<云南省1:5万诗礼
犀牛街
大河
老家库
哨街五幅区域地质矿产调查>(编号:12120114060201)
