小兴安岭北部逊克地区早古生代花岗岩年代学及岩石地球化学特征  

Geochronology and geochemical characteristics of Early Paleozoic granites in Xunke area of northern Lesser Khingan Range

作　　者：马天宇 赵立东 宋志韬 董艳秋 高永志 MA Tianyu;ZHAO Lidong;SONG Zhitao;DONG Yanqiu;GAO Yongzhi(Natural Resources Survey Institute of Heilongjiang Province,Harbin 150036,China)

机构地区：[1]黑龙江省自然资源调查院,哈尔滨150036

出　　处：《世界地质》2023年第3期433-443,共11页World Geology

基　　金：黑龙江省资源补偿费项目(HLJKD2006-11)。

摘　　要：逊克岩体位于小兴安岭北部,主要由正长花岗岩组成。锆石LA-ICP-MS U-Pb定年结果表明逊克岩体形成于中志留世(424±6)Ma。花岗岩样品具有较高的w(SiO_(2))(65.90%~72.63%),富碱w(Na_(2)O+K_(2)O)(8.87%~10.18%)和w(Al_(2)O_(3))(13.17%~17.15%),为高钾钙碱性、准铝质岩系列岩石;逊克岩体具有强烈的Eu负异常,富集大离子亲石元素(Rb、Th、K、Ba),亏损高场强元素(Nb、Ta、Ti)和P、Sr;稀土元素总量高,轻重稀土比值显示为轻稀土富集型。岩石类型为I型。低Sr、高Y特征暗示岩浆来源于中、上部地壳的部分熔融。结合前人研究成果,认为小兴安岭北部中志留世花岗岩与松嫩地块和佳木斯地块的碰撞拼合有关。The Xunke pluton is mainly composed of syenogranite,and it is located in northern Lesser Khingan Range.LA-ICP-MS zircon U-Pb dating results indicate that the Xunke pluton was formed in the Middle Silurian(424±6)Ma.The granite samples are high inw(SiO_(2))of 65.90%-72.63%,w(Na_(2)O+K_(2)O)of 8.87%-10.18%and w(Al_(2)O_(3))of 13.17%-17.15%,belonging to a high potassium-calcium-alkaline,quasi Aluminous rock series.Xunke pluton has strong negative Eu anomaly,enriched in large ionic lithophile elements(Rb,Th,K,Ba),depleted in high field strength elements(Nb,Ta,Ti)and P,Sr.The total amount of rare earth elements is high,and the ratio of light and heavy rare earth elements(LREE/HREE)suggests a light rare earth enrichment type.The rock is I type.The low Sr and high Y characteristics imply that the magma originated from partial melting of the middle and upper crust.Combined with previous research,it is suggested that the Middle Silurian granites in the northern Lesser Khingan Range are related to the collisional convergence of the Songneng and the Jiamusi massif.

关 键 词：花岗岩 中志留世 锆石U-PB定年 逊克地区 小兴安岭北部 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]