吉林南部石灰沟辉石闪长岩的地球化学特征及构造背景  

Petrogeochemical characteristics and tectonic setting of Shihuigou pyroxene diorite in Southern Jilin province

作　　者：马国骅 孙永刚 Ma Guohua;Sun Yonggang(No.5 Geological Survey Institute of Qinghai Province,Xining 810099,China;School of Resources&Civil Engineering,Suzhou University,Suzhou 234000,China)

机构地区：[1]青海省第五地质勘查院,青海西宁810099 [2]宿州学院资源与土木工程学院,安徽宿州234000

出　　处：《黑龙江科技大学学报》2022年第6期698-704,共7页Journal of Heilongjiang University of Science And Technology

基　　金：吉林省自然科学基金资助项目(20180101089JC);宿州学院2022年博士(后)科研启动基金项目(2022BSK009)。

摘　　要：为明确华北克拉通东部陆块新太古代的地球动力学背景,以吉林南部石灰沟地区新太古代辉石闪长岩为研究对象,研究其岩石学、年代学和地球化学特征。结果表明:石灰沟辉石闪长岩16个岩浆锆石测点的加权平均年龄为(2540±19)Ma,代表其结晶年龄;辉石闪长岩样品具有较低的SiO_(2)含量,较高的MgO、Cr和Ni含量。辉石闪长岩样品富集轻稀土、亏损重稀土并具有微弱Eu负异常,富集大离子亲石元素Rb、K、Th、U等,亏损高场强元素Nb、Ti、Zr、Hf等;辉石闪长岩样品具有大陆边缘弧或岛弧岩浆的特点,与大洋俯冲相关岩石的元素特征相似。研究认为石灰沟辉石闪长岩的岩浆源区为受流体或熔体交代的岩石圈地幔楔,并经历了部分熔融作用,形成于与大洋俯冲密切相关的活动大陆边缘环境。This paper aims to investigate the Neoarchean geodynamic background of the Eastern Block of the North China Craton,takes the Neoarcheanpyroxene diorites in the Shihuigou area of southern Jilin province as the research object,studying its the petrology,chronology and petrogeochemistr.The results show that the weigh average age of the 16 magmatic zircons from the Shihuigou pyroxene diorite is(2540±19)Ma,indicating the crystallization age of the pyroxene diorite;the pyroxene diorite samples have lower SiO_(2) content and higher MgO,Cr and Ni content.The pyroxene diorite samples show LREE enrichment,HREE depletion and weak negative Eu anomaly,and enrichment of large ion lithophile elementsRb,K,depletion of high field strength elements Nb,Ti,Zr and Hf.The pyroxene diorite samples have the characteristics of continental margin arc or island arc magma,which are similar to the element characteristics of ocean subduction-related rocks.Comprehensive analysis indicates that the magma source region of the pyroxene diorite is the lithosphere mantle wedge through fluid or melt metasomatism,undergoing partial melting,andformed in an active continental margin environment closely related to ocean subduction.

关 键 词：华北克拉通 辉石闪长岩 新太古代 岩石成因 构造背景 

分 类 号：P597[天文地球—地球化学]