北黄海盆地花岗斑岩锆石U-Pb年代学、地球化学及其地质意义
发布时间：2018-10-12 08:39
【摘要】：北黄海盆地X1和X2钻井岩心揭示上侏罗统中有侵入的花岗质岩石,镜下鉴定其为花岗斑岩。对花岗斑岩进行了主量、微量和稀土元素测试分析,样品的Si O2含量介于70.22%~71.88%之间,K2O/Na2O比值介于0.95~1.68之间,A/CNK比值介于0.75~1.12之间,有高钾钙碱性、弱碱质-偏铝质性质。微量元素组成富集Rb、Th、U等元素,相对亏损Nb、Eu、Sr等元素。稀土总量较高(∑REE=50.38×10-6~162.27×10-6),轻稀土(LREE)相对富集(LREE/HREE=6.86~25.43,(La/Yb)N=10.06~57.76),具有明显的Eu负异常(?Eu=0.65~0.83)。样品的Th含量高,与Rb呈正相关性,综合主量元素特征(A/CNK1.1),判别其为I型花岗岩。LA-ICP-MS锆石U-Pb测年结果表明X1井花岗斑岩年龄为110±1 Ma,X2井花岗斑岩年龄108±1 Ma、107±1 Ma,形成于早白垩世晚期。结合区域构造背景及岩石地球化学特征认为,北黄海盆地花岗斑岩形成于板块碰撞后的伸展构造背景。
[Abstract]:The core of X1 and X2 drilling in northern Huang Hai basin reveals intrusive granitic rocks in Upper Jurassic, which are identified as granitic porphyry under microscope. The main amount, trace and rare earth elements of granitic porphyry were measured and analyzed. The results show that the content of Si O 2 is 71.88%, the ratio of K2O/Na2O is between 0.95 and 1.68, and the ratio of A/CNK is between 0.75 and 1.12. The trace elements are rich in Rb,Th,U and other elements, and are relatively depleted in elements such as Nb,Eu,Sr. The total amount of rare earth is relatively high (鈭，
本文编号：2265490
[Abstract]:The core of X1 and X2 drilling in northern Huang Hai basin reveals intrusive granitic rocks in Upper Jurassic, which are identified as granitic porphyry under microscope. The main amount, trace and rare earth elements of granitic porphyry were measured and analyzed. The results show that the content of Si O 2 is 71.88%, the ratio of K2O/Na2O is between 0.95 and 1.68, and the ratio of A/CNK is between 0.75 and 1.12. The trace elements are rich in Rb,Th,U and other elements, and are relatively depleted in elements such as Nb,Eu,Sr. The total amount of rare earth is relatively high (鈭，
本文编号：2265490
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