地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2015年
8期
1502-1516
,共15页
聂政融%王晓霞%柯昌辉%杨阳%吕星球
聶政融%王曉霞%柯昌輝%楊暘%呂星毬
섭정융%왕효하%가창휘%양양%려성구
LA-ICP-MS锆石U-Pb年龄%锆石Hf同位素%岩石成因%华北地块南缘
LA-ICP-MS鋯石U-Pb年齡%鋯石Hf同位素%巖石成因%華北地塊南緣
LA-ICP-MS고석U-Pb년령%고석Hf동위소%암석성인%화북지괴남연
LA-ICP-MS zircon U-Pb age%zircon Hf isotope%genesis of rocks%southern margin of North China Block
花山复式岩体位于华北地块南缘,采用LA-ICP-MS技术测得复式岩体中的中细粒似斑状黑云二长花岗岩的锆石U-Pb年龄为128±1Ma,此年龄被解释为成岩年龄。该岩体及邻近的五丈山岩体中花岗岩具有高硅、富碱特征,为准铝-弱过铝质高钾钙碱性系列;在稀土和微量元素上,富集LREE、Rb、Ba、K、Sr等大离子亲石元素,亏损HREE、Zr、Hf、Ta、Nb、P、Ti等高场强元素,总体上Eu异常不明显,显示出I-A过渡型花岗岩的特征。锆石Lu-Hf同位素组成表明,花山花岗岩的εHf(t)主要变化于-25.8~-19.6之间,tDM2为2.81~2.43Ga,显示源区物质以古老的壳源物质为主,有年轻组分的参与。与岩体外围多金属成矿年龄的对比分析发现,外围金、钼矿床与花山复式岩体的年龄一致,比五丈山岩体晚20~25Ma,表明金、钼矿的形成与花山岩体在时空上联系密切,该岩体可能为成矿提供了热源。
花山複式巖體位于華北地塊南緣,採用LA-ICP-MS技術測得複式巖體中的中細粒似斑狀黑雲二長花崗巖的鋯石U-Pb年齡為128±1Ma,此年齡被解釋為成巖年齡。該巖體及鄰近的五丈山巖體中花崗巖具有高硅、富堿特徵,為準鋁-弱過鋁質高鉀鈣堿性繫列;在稀土和微量元素上,富集LREE、Rb、Ba、K、Sr等大離子親石元素,虧損HREE、Zr、Hf、Ta、Nb、P、Ti等高場彊元素,總體上Eu異常不明顯,顯示齣I-A過渡型花崗巖的特徵。鋯石Lu-Hf同位素組成錶明,花山花崗巖的εHf(t)主要變化于-25.8~-19.6之間,tDM2為2.81~2.43Ga,顯示源區物質以古老的殼源物質為主,有年輕組分的參與。與巖體外圍多金屬成礦年齡的對比分析髮現,外圍金、鉬礦床與花山複式巖體的年齡一緻,比五丈山巖體晚20~25Ma,錶明金、鉬礦的形成與花山巖體在時空上聯繫密切,該巖體可能為成礦提供瞭熱源。
화산복식암체위우화북지괴남연,채용LA-ICP-MS기술측득복식암체중적중세립사반상흑운이장화강암적고석U-Pb년령위128±1Ma,차년령피해석위성암년령。해암체급린근적오장산암체중화강암구유고규、부감특정,위준려-약과려질고갑개감성계렬;재희토화미량원소상,부집LREE、Rb、Ba、K、Sr등대리자친석원소,우손HREE、Zr、Hf、Ta、Nb、P、Ti등고장강원소,총체상Eu이상불명현,현시출I-A과도형화강암적특정。고석Lu-Hf동위소조성표명,화산화강암적εHf(t)주요변화우-25.8~-19.6지간,tDM2위2.81~2.43Ga,현시원구물질이고로적각원물질위주,유년경조분적삼여。여암체외위다금속성광년령적대비분석발현,외위금、목광상여화산복식암체적년령일치,비오장산암체만20~25Ma,표명금、목광적형성여화산암체재시공상련계밀절,해암체가능위성광제공료열원。
The Huashan granitoid pluton is located on the southern margin of the North China Block. Zircon LA-ICP-MS dating of the porphyritic monzogranites from the Huashan pluton yielded an age of 128 ± 1Ma. This pluton and its neighboring Wuzhang?shan pluton are of high K calc-alkaline series and belong to metaluminous to weak peraluminous rocks. They are enriched in large ion lithophile elements (LREE, Rb, Ba, K, Sr) and depleted in high-field strength elements (HREE, Zr, Hf, Ta, Nb, P, Ti), with in?significant Eu anomaly. These characteristics suggest that the granitoids have I-A type granite features. The zircon εHf(t) values and tDM2 values of the Huashan porphyritic monzogranites range from-25.8 to-19.6 and from 2.81Ga to 2.43Ga respectively, showing that their sources were mainly ancient crustal material with the addition of some juvenile components. The ages of gold, molybde?num deposits near the Huashan pluton are identical with those of the Huashan pluton, but are 20~25Ma younger than the age of Wu?zhangshan pluton. The formation of gold molybdenum deposits was close to the formation of Huashan granitoid pluton in time and space. This pluton might have provided a thermal source for the mineralization.