| 碾子山晶洞碱性花岗岩矿物-水氧同位素交换反应动力学 |
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| 引用本文： | 赵子福,郑永飞,魏春生.碾子山晶洞碱性花岗岩矿物-水氧同位素交换反应动力学[J].地球化学,2001,30(2):177-185. |
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| 作者姓名： | 赵子福 郑永飞 魏春生 |
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| 作者单位： | 中国科学技术大学地球和空间科学系化学地球动力学研究实验室, |
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| 基金项目： | 国家自然科学基金资助项目! (40033010； 49603043 |
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| 摘 要： | 对黑龙江碾子山碱性花岗岩的全岩及其主要单矿物进行了氧同位素分析，结果表明，全岩和单矿物不仅δ^18O 值变化范围较大（全岩－2．4－2．0‰，石英0．0－5．8‰，碱性长石－3．8－0．1‰，磁铁矿－8．5－1．0‰），而且强烈亏损^18O。共生矿物之间表现出明显不平衡的氧同位素分馏特征，指示在花岗岩侵位之后与水之间发生了同位素交换，根据锆石和现代大气降水的氧同位素组成，对岩石与外来流体的δ^18O值进行了估计，多维矿水－岩反应时限约为0．3－3Ma，水／岩比（氧摩尔比）介于0．11－1．02之间。水－岩反应温度较高（约400度）和反应时间较长是导致石英δ^18O值降低的主要原因。
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| 关 键 词： | 碱性花岗岩 氧同位素 水－岩反应 交换动力学 黑龙江 矿物分析 |
| 文章编号： | 0379-1726(2001)02-0177-09 |
| 修稿时间： | 2000年9月25日 |
Kinetics of oxygen isotope exchange between water and minerals of miarolitic alkaline granite from Nianzishan |
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| ZHAO Zi-fu,ZHENG Yong-fei,WEI Chun-sheng.Kinetics of oxygen isotope exchange between water and minerals of miarolitic alkaline granite from Nianzishan[J].Geochimica,2001,30(2):177-185. |
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| Authors: | ZHAO Zi-fu ZHENG Yong-fei WEI Chun-sheng |
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| Abstract: | The oxygen isotopic compositions of whole rocks and single minerals were measured for alkaline granites from Nianzishan in Heilongjiang Province. The results show that the whole rocks and single minerals have widely variable δ18O values (-2.4‰～2.0‰for whole rock, 0.0‰～5.8‰ for quartz,-3.8‰～0.1‰for alkaline feldspar, and -8.5‰～-1.0‰for magnetite), and depleted in 18O. Oxygen isotope disequilibrium is observed between the coexisting minerals, indicating water-rock exchange for the alkaline granite during its emplacement.The initial δ18O values of rock and external fluid are estimated according to the oxygen isotopic compositions of
zircons and modern meteoric water. Quantitative simulation was carried out by using the kinetic model of oxygen isotope exchange between multi-minerals and water. It is obtained that the flow rate of fluid is about 1×10-15～3×10-14 mol/s , the time of water-rock interaction is about 0.3～3Ma, and ratio of water to rock is about 0.11～1.02. Significant decrease in quartz δ18O is ascribed to water-rock interaction of higher temperatures (～400℃)
and longer time (＞1Ma). |
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| Keywords: | alkaline granite oxygen isotope water- rock interaction exchange kinetics Nianzishan Heilongjiang Province |
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