CAJ | 학술논문

巴尔哲矿床中的矿化和非矿化碱性花岗岩主要造岩矿物均为微斜长石、石英、钠闪石和钠长石,但其相对含量及颗粒大小明显不同,且两类岩石中包裹体的组成特征及锆石的结晶习性也有显著差异.主量元素分析显示,矿化与非矿化碱性花岗岩均以富硅、富碱、贫镁和钙为特征,为较典型的非造山A型花岗岩.尽管矿化碱性花岗岩中K_2O和Na_2O的含量均没有明显的增加,但其Na+K/Al、Na_2O+K_2O/CaO、FeO~*/MgO及K_2O/MgO等岩石化学参数与非矿化碱性花岗岩明显不同.在矿化碱性花岗岩中除了矿化的稀土元素及Nb、Zr强烈富集外,U、Th及Y也明显富集,而Ba、Sr、P、Eu和Ti表现为强烈的亏损.在非矿化碱性花岗岩中除了大离子亲石元素Rb略有富集外,稀土元素、Nb、Zr、U、Th、Ta及Y并无明显富集,虽然Sr、P、Eu和Ti也表现为亏损,但与矿化碱性花岗岩相比其亏损程度明显降低.岩相学、岩石化学及微量元素地球化学特征显示,矿化碱性花岗岩不可能是非矿化碱性花岗岩硅化和钠长石化作用的产物,二者应是同一岩浆体系不同演化阶段熔体固结的产物.K/Rb、Rb/Sr及δEu等地球化学参数显示,矿化碱性花岗岩是高演化A型花岗质熔体固结的产物;而岩石学、包裹体及地球化学特征则显示,这种高演化的A型花岗质熔体已经进入了岩浆一热液过渡阶段.巴尔哲矿床稀有稀土元素的超常富集和成矿与A型花岗岩的高演化过程密切相关.
파이철광상중적광화화비광화감성화강암주요조암광물균위미사장석、석영、납섬석화납장석,단기상대함량급과립대소명현불동,차량류암석중포과체적조성특정급고석적결정습성야유현저차이.주량원소분석현시,광화여비광화감성화강암균이부규、부감、빈미화개위특정,위교전형적비조산A형화강암.진관광화감성화강암중K_2O화Na_2O적함량균몰유명현적증가,단기Na+K/Al、Na_2O+K_2O/CaO、FeO~*/MgO급K_2O/MgO등암석화학삼수여비광화감성화강암명현불동.재광화감성화강암중제료광화적희토원소급Nb、Zr강렬부집외,U、Th급Y야명현부집,이Ba、Sr、P、Eu화Ti표현위강렬적우손.재비광화감성화강암중제료대리자친석원소Rb략유부집외,희토원소、Nb、Zr、U、Th、Ta급Y병무명현부집,수연Sr、P、Eu화Ti야표현위우손,단여광화감성화강암상비기우손정도명현강저.암상학、암석화학급미량원소지구화학특정현시,광화감성화강암불가능시비광화감성화강암규화화납장석화작용적산물,이자응시동일암장체계불동연화계단용체고결적산물.K/Rb、Rb/Sr급δEu등지구화학삼수현시,광화감성화강암시고연화A형화강질용체고결적산물;이암석학、포과체급지구화학특정칙현시,저충고연화적A형화강질용체이경진입료암장일열액과도계단.파이철광상희유희토원소적초상부집화성광여A형화강암적고연화과정밀절상관.
The major rock-forming minerals are same in both barren and mineralized alkaline granites at the Baerzhe deposit,mainly composed of microcline,quartz,riebeckite and albite.However,their relative contents and grain sizes are obviously different,as well as the compositions of fluid inclusions and the crystal habits of zircon also show significant differences in these two types of granites.The data on petrology,petroehemistry and element geochemistry suggest that the mineralized alkaline granite is not formed by means of the silicification and albitization of barren alkaline granite.The data also confirmed that these two types of granites are products of crystallization from a same magrnatie system at different positions belonging different evolutional stages.And the characteristics on petrology,inclusions and geochemistry show that the highly evolved A-type granitic melt has stepped into magmatic-hydrothemal transition stage.The extraordinary enrichment and mineralization of rare and rare earth elements are closely related to the highly evolved A-type granite in the Baerzhe deposit.