地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2014年
9期
1333-1341
,共9页
耿雯%秦江锋%李永飞%赖绍聪
耿雯%秦江鋒%李永飛%賴紹聰
경문%진강봉%리영비%뢰소총
黑云母花岗岩%地球化学特征%LA-ICP-MS锆石U-Pb年龄%岩石成因
黑雲母花崗巖%地毬化學特徵%LA-ICP-MS鋯石U-Pb年齡%巖石成因
흑운모화강암%지구화학특정%LA-ICP-MS고석U-Pb년령%암석성인
biotite granite%geochemistry%LA-ICP-MS zircon U-Pb age%petrogenesis
对张广才岭南部一面坡花岗岩的地质学、岩石学、地球化学及锆石U-Pb年龄研究表明,岩石富硅富铝,属于过铝质岩石(A/CNK=1.04~1.07),全碱(K2O+Na2O)含量为8.24%~8.85%,K2O/Na2O值为1.58~1.68,属于高钾钙碱性系列I型花岗岩。岩石富集LREE、Rb、Th、U、K,相对亏损Nb、Ta、P、Ti,具有明显的Eu负异常,LA-ICP-MS锆石206Pb/238U年龄加权平均值为211Ma ±4Ma(MSWD=1.4,2σ),代表了花岗岩的结晶年龄。岩石具有相对亏损的锆石Hf同位素组成(εHf(t)=+1.75~+13.81),TDM2为367~1136Ma。结合区域构造环境分析,认为一面坡晚三叠世花岗岩属于I型花岗岩,可能形成于后碰撞伸展构造环境,是岩石圈伸展阶段新增生下地壳物质发生部分熔融的产物。
對張廣纔嶺南部一麵坡花崗巖的地質學、巖石學、地毬化學及鋯石U-Pb年齡研究錶明,巖石富硅富鋁,屬于過鋁質巖石(A/CNK=1.04~1.07),全堿(K2O+Na2O)含量為8.24%~8.85%,K2O/Na2O值為1.58~1.68,屬于高鉀鈣堿性繫列I型花崗巖。巖石富集LREE、Rb、Th、U、K,相對虧損Nb、Ta、P、Ti,具有明顯的Eu負異常,LA-ICP-MS鋯石206Pb/238U年齡加權平均值為211Ma ±4Ma(MSWD=1.4,2σ),代錶瞭花崗巖的結晶年齡。巖石具有相對虧損的鋯石Hf同位素組成(εHf(t)=+1.75~+13.81),TDM2為367~1136Ma。結閤區域構造環境分析,認為一麵坡晚三疊世花崗巖屬于I型花崗巖,可能形成于後踫撞伸展構造環境,是巖石圈伸展階段新增生下地殼物質髮生部分鎔融的產物。
대장엄재령남부일면파화강암적지질학、암석학、지구화학급고석U-Pb년령연구표명,암석부규부려,속우과려질암석(A/CNK=1.04~1.07),전감(K2O+Na2O)함량위8.24%~8.85%,K2O/Na2O치위1.58~1.68,속우고갑개감성계렬I형화강암。암석부집LREE、Rb、Th、U、K,상대우손Nb、Ta、P、Ti,구유명현적Eu부이상,LA-ICP-MS고석206Pb/238U년령가권평균치위211Ma ±4Ma(MSWD=1.4,2σ),대표료화강암적결정년령。암석구유상대우손적고석Hf동위소조성(εHf(t)=+1.75~+13.81),TDM2위367~1136Ma。결합구역구조배경분석,인위일면파만삼첩세화강암속우I형화강암,가능형성우후팽당신전구조배경,시암석권신전계단신증생하지각물질발생부분용융적산물。
This paper has reported the field geology, petrography, major and trace elements, zircon U-Pb age and Lu-Hf isotopic da-ta for the granite from Yimianpo area, Zhangguangcai Mountain. The granite is high in SiO 2 and Al2O3. A/CNK=1.04~1.07, (K2O+Na2O)=8.24%~8.85%,and K2O/Na2O=1.58~1.68, belonging to peraluminous and I-type high-K calc-alkaline series. The granite is enriched in LREE, Rb, Th, U, K and depleted in Nb, Ta, P, Ti with significant negative Eu anomalies. It has 206Pb/238U weighted mean age of 211Ma±4Ma (MSWD=1.4, 2σ), which represents the crystallization age of the granite. Zircon Hf isotope composition isεHf(t)=+1.75~+13.81, TDM2=367~1136Ma. Therefore, the I-type granite in the study area might have been formed in a typical post-collsional tectonic setting and resulted from partial melting of juvenile basaltic lower crust in an extensional setting.