CAJ | 학술논문

利用微钻取样技术和微量样品Rb-Sr同位素分析方法,本文对出露在东秦岭造山带的中生代合峪花岗岩的自形钾长石巨晶进行微区-微量样品Rb-Sr同位素组成分析.分析结果表明,钾长石斑晶具有显著的Rb/Sr比值和Sr同位素组成变化,斑晶和基质钾长石均构成年龄为132～133Ma的Rb-Sr等时线,代表岩浆的后期冷却时代.钾长石晶体的初始~(87)Sr/~(86)Sr比值由边缘相到中心相没有明显的变化,代表花岗质岩浆结晶阶段的Sr同位素组成,暗示合峪花岗岩的钾长石巨晶为原生成因.以高空间分辨率为特征,微区取样技术已经广泛地应用在变质岩和深成岩浆岩的同位素年代学和成因研究.结合微量样品同位素分析技术,微区-微量样品Rb-Sr同位素方法有望在火山岩的成因和年代学方面得到应用.
이용미찬취양기술화미량양품Rb-Sr동위소분석방법,본문대출로재동진령조산대적중생대합욕화강암적자형갑장석거정진행미구-미량양품Rb-Sr동위소조성분석.분석결과표명,갑장석반정구유현저적Rb/Sr비치화Sr동위소조성변화,반정화기질갑장석균구성년령위132～133Ma적Rb-Sr등시선,대표암장적후기냉각시대.갑장석정체적초시~(87)Sr/~(86)Sr비치유변연상도중심상몰유명현적변화,대표화강질암장결정계단적Sr동위소조성,암시합욕화강암적갑장석거정위원생성인.이고공간분변솔위특정,미구취양기술이경엄범지응용재변질암화심성암장암적동위소년대학화성인연구.결합미량양품동위소분석기술,미구-미량양품Rb-Sr동위소방법유망재화산암적성인화년대학방면득도응용.
This study presents analytical data of Rb-Sr isotopic composition of K-feldspar megacrysts from the Mesozoic Heyu granite pluton exposed in the eastern Qinling orogenic belt, by using the micro-drilling technique and the micro-sample Rb-Sr isotopic analytical method. Analytical results show significant variations in Rb/Sr ratio and Sr isotopic composition within a single K-feldspar crystal. Rb-Sr isochron ages of about 132 Ma to 133 Ma can be obtained from both megacryst and matrix K-feldspars. No significant variations of ~(87)Sr/~(86)Sr initial ratio can be detected in the centre and marginal parts of K-feldspar crystals, suggesting homogeneous Sr isotopic composition during the crystallization of the magma and implying primary origin for the K-feldspar megacrysts of the Heyu granite. Owing the feature of high spatial resolution, a combination of the micro-drilling technique and the micro-sample Rb-Sr isotopic analytical method increases the applications in studies on isotopic geochronology and petrogenesis of metamorphic and plutonic rocks as well as volcanic rocks.