马来西亚麻元锡矿床成矿花岗岩地球化学、锆石U-Pb年龄及Sr-Nd-Hf同位素特征  

Geochemistry,zircon U-Pb geochronology and Sr-Nd-Hf isotopic characteristics of the ore-forming granite in the Mayah tin deposit,Malaysia

作　　者：戴雪灵 尹萍[2] 杨柳[2] 张启源[3] JASMI Hafiz Abdul Aziz DAI Xue-ling;YIN Ping;YANG Liu;Khai Yuen Chong;JASMI Hafiz Abdul Aziz(Hunan Gold Group,Changsha 410083,China;Hunan Engineering Polytechnic,Changsha 410083,China;Department of Geology,Faculty of Science,University ofMalaya,Kuala Lumpur 50603,Malaysia)

机构地区：[1]湖南黄金集团,湖南长沙410083 [2]湖南工程职业技术学院,湖南长沙410083 [3]马来亚大学理学院地质系,马来西亚吉隆坡50603

出　　处：《矿物学报》2022年第2期163-175,共13页Acta Mineralogica Sinica

基　　金：湖南省自然科学基金项目(编号:2018JJ5012)。

摘　　要：麻元锡矿床是马来半岛东部花岗岩带内重要原生锡矿之一。为厘定矿区成矿花岗岩的形成时间及构造背景,本文开展了岩石学、锆石U-Pb年代学、岩石地球化学、Sr-Nd同位素及锆石Hf同位素研究。对2件矿区花岗岩样品的锆石进行了LA-ICP-MS U-Pb测试,获得了^(207)Pb/^(206)Pb-238U/^(206)Pb谐和年龄分别为(259.0±3.3)Ma(MSWD=0.77)和(261.3±2.8)Ma(MSWD=0.55),加权平均年龄为(260.30±2.0)Ma(MSWD=1.3)及(263.0±2.1)Ma(MSWD=0.15)。岩石地球化学分析显示,矿区花岗岩样品富SiO_(2)(73.09%~76.56%)、富K_(2)O(4.29%~4.91%),I_(A/CNK)为1.03~1.06,轻稀土富集(LREE/HREE为4.24~8.08),Eu负异常明显(δEu=0.08~0.20),富含大离子亲石元素(Rb、K、Th、U),亏损高场强元素(Nb、Ti)。样品全岩(^(87)Sr/^(86)Sr)_(i)为0.6991~0.7087、ε_(Nd)(t)为-5.30~-1.77、二阶段Nd模式年龄t_(DM2)为1.04~1.28 Ga。锆石ε_(Hf)(t)为-3.5~0.8,t_(DM2)=1.24~1.51 Ga。分析结果表明,麻元锡矿成矿花岗岩为高分异的高钾钙碱性I型花岗岩,成岩时代为中二叠世,形成于活动大陆边缘的岩浆弧构造环境,是特提斯洋向印支板块下俯冲消减过程中弧地壳熔融的产物。The Mayah tin deposit is one of important primary tin deposits in the eastern granite belt of the Malaysia peninsular.Petrology,zircon U-Pb geochronology,lithogeochemistry,Sr-Nd isotopes and zircon Hf isotopes have been carried out in this paper in order to reveal the formation time and tectonic setting of the ore-forming granite of the Mayah tin deposit in the Kuantan area,Malaysia.LA-ICP-MS analyses show that the zircon ^(207)Pb/^(206)Pb-238U/^(206)Pb concordant ages of two granite samples in the deposit are 259.0±3.3 Ma(MSWD=0.77)and 261.3±2.8 Ma(MSWD=0.55),respectively,with the respective corresponding weighted mean ages of 260.30±2.0 Ma(MSWD=1.3)and 263.0±2.1 Ma(MSWD=0.15).Geochemical analyses suggest that these granite samples are rich in SiO_(2)(73.09%-76.56%)and K_(2)O(4.29%-4.91%),enriched in large-ion lithophile elements(Rb,K,Th,U),but depleted in high field strength elements(Nb,Ti),with I_(A/CNK) ratios of 1.03-1.06,enriched LREE(LREE/HREE ratios of 4.24-8.08),and remarkably negative Eu anomalies(δEu=0.08-0.20).The bulk rock samples have(^(87)Sr/^(86)Sr)_(i) ratios varying from 0.69910 to 0.708692,ε_(Nd)(t)values ranging from-5.30 to-1.77,and the T_(DM2) mode ages of 1.04-1.28 Ga.Their zircon ε_(Hf)(t)values range from-3.5 to 0.8,with two-stage model ages(T_(DM2))of 1.24-1.51 Ga.Based on the above analytical results,it is believed that the ore-related granite in the Mayah tin deposit belongs to the highly fractionated high-K calc-alkaline I-type granite which was produced by the magma derived from the arc crustal anatexis in the subduction process of the Paleo-Tethyan oceanic lithosphere toward the Indosinian block in the magmatic arc tectonic setting of the active continental margin at Middle Permian.

关 键 词：马来西亚 麻元锡矿床 锆石U-PB定年 地球化学特征 

分 类 号：P588.121[天文地球—岩石学]