中山大学学报(自然科学版)
中山大學學報(自然科學版)
중산대학학보(자연과학판)
ACTA SCIENTIARUM NATURALIUM UNIVERSITATIS SUNYATSENI
2013年
5期
161-168
,共8页
李鹏举%余心起%邱骏挺%李红英%周翔
李鵬舉%餘心起%邱駿挺%李紅英%週翔
리붕거%여심기%구준정%리홍영%주상
含矿性%氧逸度%铜金钼矿床%燕山期花岗岩%浙赣皖相邻区
含礦性%氧逸度%銅金鉬礦床%燕山期花崗巖%浙贛皖相鄰區
함광성%양일도%동금목광상%연산기화강암%절공환상린구
ore-bearing potential%oxygen fugacity%Cu,Au,Mo deposit%Yanshanian granites%the in-tersection region between zhejiang%Anhui and Jiangxi Provinces
对浙赣皖相邻区燕山期两类花岗岩的岩石学、地球化学及成矿元素研究发现,燕山早期岩体主要岩石类型为花岗闪长岩,岩石偏中性,成矿元素方面更富含Au、Ag、Cu、Mo、Ni等深源元素,研究区大部分铜金钼矿床都与其有关;燕山晚期岩体主要岩石类型是花岗(斑)岩,岩石偏酸性,成矿元素相对缺乏Au、Ag、Cu、Mo、Ni等深源元素,与之伴生的铜金钼矿床罕见。可见,花岗质侵入体与研究区的金、铜、钼等成矿作用密切相关。通过锆石Ce异常计算出的岩浆氧逸度结果显示,早期花岗质侵入体的氧逸度范围介于FMQ (铁橄榄石-磁铁矿-石英缓冲对)和MH (磁铁矿-赤铁矿缓冲对)之间,平均值为FMQ+2.7,氧逸度较高;晚期氧逸度小于FMQ,平均值为FMQ-1.1。因此,氧逸度对部分元素(如铜、金、钼)的成矿有重要影响,氧逸度高,更有利于形成铜、金、钼等矿床。由于锆石成分分析的普及,获得锆石中的稀土微量元素含量越来越便利,利用锆石成分来计算岩浆的氧逸度具有非常广阔的应用前景。
對浙贛皖相鄰區燕山期兩類花崗巖的巖石學、地毬化學及成礦元素研究髮現,燕山早期巖體主要巖石類型為花崗閃長巖,巖石偏中性,成礦元素方麵更富含Au、Ag、Cu、Mo、Ni等深源元素,研究區大部分銅金鉬礦床都與其有關;燕山晚期巖體主要巖石類型是花崗(斑)巖,巖石偏痠性,成礦元素相對缺乏Au、Ag、Cu、Mo、Ni等深源元素,與之伴生的銅金鉬礦床罕見。可見,花崗質侵入體與研究區的金、銅、鉬等成礦作用密切相關。通過鋯石Ce異常計算齣的巖漿氧逸度結果顯示,早期花崗質侵入體的氧逸度範圍介于FMQ (鐵橄欖石-磁鐵礦-石英緩遲對)和MH (磁鐵礦-赤鐵礦緩遲對)之間,平均值為FMQ+2.7,氧逸度較高;晚期氧逸度小于FMQ,平均值為FMQ-1.1。因此,氧逸度對部分元素(如銅、金、鉬)的成礦有重要影響,氧逸度高,更有利于形成銅、金、鉬等礦床。由于鋯石成分分析的普及,穫得鋯石中的稀土微量元素含量越來越便利,利用鋯石成分來計算巖漿的氧逸度具有非常廣闊的應用前景。
대절공환상린구연산기량류화강암적암석학、지구화학급성광원소연구발현,연산조기암체주요암석류형위화강섬장암,암석편중성,성광원소방면경부함Au、Ag、Cu、Mo、Ni등심원원소,연구구대부분동금목광상도여기유관;연산만기암체주요암석류형시화강(반)암,암석편산성,성광원소상대결핍Au、Ag、Cu、Mo、Ni등심원원소,여지반생적동금목광상한견。가견,화강질침입체여연구구적금、동、목등성광작용밀절상관。통과고석Ce이상계산출적암장양일도결과현시,조기화강질침입체적양일도범위개우FMQ (철감람석-자철광-석영완충대)화MH (자철광-적철광완충대)지간,평균치위FMQ+2.7,양일도교고;만기양일도소우FMQ,평균치위FMQ-1.1。인차,양일도대부분원소(여동、금、목)적성광유중요영향,양일도고,경유리우형성동、금、목등광상。유우고석성분분석적보급,획득고석중적희토미량원소함량월래월편리,이용고석성분래계산암장적양일도구유비상엄활적응용전경。
Two intense tectonic-magmatic activities during the Yanshanian have been identified in the adjacent area of Zhejiang,Jiangxi,and Anhui provinces (the WZG region).Correspondingly,there are two entirely different kinds of granites.The early Yanshanian granites are composed of granodiorite,and the rock is nearly neutral,enriched in Au,Ag,Cu,Mo,and Ni elements.The late Yanshanian granites are composed of granite porphyry,and the rock is acidic,depleted in these metallogenic elements. Therefore,the Cu,Au,Mo mineralization in the study region is related to these Yanshanian plutons.The oxygen fugacity (fO2 )of the magma calculated by zircon Ce anomalies and Ti-in-zircon temperatures shows that the average magmatic fO2 for the early Yanshanian granites in the study area is fayalite-magne-tite-quartz (FMQ)+2.7 ,much higher than that of the late Yanshanian granites (FMQ -1.1 ).Thus, the high oxygen fugacity contributes to the formation of Cu,Au,and Mo deposits.With the popularity of the zircon analysis,it is much easier to obtain the content of rare earth elements in zircon.Using zircon trace element to calculate the oxygen fugacity tends to have a broad prospect.