摘要
营厂岩体分布于辽北西丰县和隆镇境内,研究结果表明,该岩体主要为似斑状二长花岗岩,锆石^(206) Pb/^(238) U年龄加权平均值为156.1 Ma±1.5 Ma,形成时代为晚侏罗世。营厂岩体w(Na_(2)O)/w(K_(2)O)平均值为1.07,属高钾钙碱性系列;里特曼指数σ平均值为2.15,属钙碱系列;铝饱和指数A/CNK平均值为1.16,A/CN平均值为1.99,属过铝型;Rb、Sr、Ba、Th、Hf含量偏高,Cr、Ni、Co、V、Rb、Zr、Nb等元素含量低,为“S”型花岗岩特征。稀土元素总量平均值为w(ΣREE)=82.80×10^(-6),w(LREE)/w(HREE)=15.76,w(La)_(N)/w(Yb)_(N)=24.32,表明其轻稀土相对富集,重稀土相对亏损,稀土配分曲线右倾。δEu=0.80,铕弱负异常,说明成因与板块运动有关,w(Sm)/w(Nd)=0.20,w(Ba)/w(Sr)=1.60,w(K)/w(Rb)=249.15,表明具有壳源性质。营厂岩体具有埃达克岩的特点,其属于受太平洋板块向欧亚板块俯冲作用的影响,在挤压环境下加厚下地壳部分熔融,从而形成活动陆缘型花岗岩。
The Yingchang pluton occurs at Helong town,Xifeng county,the North Liaoning province.Lithologically it is dominated by porphyritic mozonitic granit.The weighted^(206) Pb/^(238) U age is 156.1 Ma±1.5 Ma corresponding to Late Jurassic Epoch.w(NaO_(2))of the pluton is averagely 1.07 suggesting that it belongs to high K calc-alkaline series;Rittman index,averagely 2.15,calc-alkaline series;A/CNK,averagely 1.16 and A/CN 1.99,pera-luminous type;high Rb,Sr,Ba,Th,Hf and low Cr,Ni,Co,V,Rb,Zr,Nb,“S”type of granite.The average w(REE)is 82.80×10^(-6),w(LREE)/w(HREE)15.76 and w(La)/w(Yb)24.32 indicating that it is relatively rich in LREE,relatively depleted in HREE with right-leaning REE distribution curve and weak negative Eu(Eu=0.80)anomaly.Thus it is a plate-movement-related pluton and w(Sm)/w(Nd)=0.20,w(Ba)/w(Sr)=1.60 and w(K)/w(Rb)=249.15 are the characteristic of crustal material.The mentioned above show that the pluton is of characteristics of adakite formed as active continental marginal granite by partial melting of lower crustal material under thickening crust condition due to compression during subduction of Pacific ocean plate under Eurasian plate.
作者
彭游博
刘文彬
赵军
姚玉健
刘锦
梁斯文
PENG Youbo;LIU Wenbin;ZHAO Jun;Yao Yujian;LIU Jin;Liang Siwen(Liaoning Survey Academy of Geology and Mineral Resources Co,.Ltd,Shenyang 110031,China;College of Earth Sciences,Jilin University,Changchun 130061,China)
出处
《地质找矿论丛》
CAS
2022年第3期344-353,共10页
Contributions to Geology and Mineral Resources Research
基金
中国地质调查局辽东—吉南成矿带永吉—凤城地区地质矿产调查项目(编号:DD20160049)资助。
关键词
营厂岩体
侏罗纪
花岗岩
锆石U-PB年龄
岩石地球化学特征
辽北
Yingchang pluton
Jurassic
granite
zircon U-Pb age
petro-geochemical characteristics
the North Liaoning province