机构地区: 中国科学院地球化学研究所矿床地球化学国家重点实验室
出 处: 《吉林大学学报(地球科学版)》 2009年第4期676-688,共13页
摘 要: 苏鲁遣山带花岗岩SiO2质量分数变化范围为71.3%-74.5%,以富碱(Na2O+K2O为8.66%-9.60%)、高钾(K20为4.95%-5.89%)、富轻稀土元素而亏损重稀土元素、明显的负铕异常(3Eu=0.51-0.61)、较高的Ga/Al(×10^4)比值(2.85-3.41)和Zr+Nb+Ce+Y值(384-714)×10^-6、富集Rb、Th、K、La、Nd、Hf、Zr和Pb以及亏损Ba、Ta、P和Ti为特征。主微量元素研究表明,所研究花岗岩为过铝质(A/KNC为1.90-2.17)A型花岗岩,为华北板块富集岩石圈地幔的部分熔融的产物。岩浆在上升侵位的过程中没有受到地壳物质的混染,但在成岩过程中存在斜长石、钾长石、黑云母、磷灰石和钛铁矿等矿物的分离结晶作用,锆石饱和温度计算表明岩浆的结晶温度大致为876-961℃。 We reported the major and trace element data of the granites from the Sulu orogenic belt.The granites are characterized li, potassium and LREE, but addition to these, the granites tents (384 - 714) × 10^-6. On by high SiO2 contents varying from 71.3% to 74.5 %, enrichment in alkadepletion in HREE, with negative Eu anomalies(3Eu=0.51 -0.61). In have high Ga/Al(×10^4) ratios (2.85 -3.41) , and Zr+Nb-t-Ce+Y conprimitive mantle-normalized spider diagrams, the granites show positive Rb, Th, K, La, Nd, Hf, Zr and Pb anomalies and negative Ba, Ta, P and Ti anomalies. This indicates that these granites are peraluminous, typical A-type granites. These A-type granites could be derived from partial melting of the enriched lithospheric mantle beneath the North China Craton (NCC). The magma underwent intense mineral fractional crystallization such as plagioclase, K-feldspar, biotite, and apatite, but no crustal contamination. The calculated zircon saturation temperatures (TZr) for A-type granites are between 876℃ and 961℃, representing the crystalline temperature of the magma.