| 摘要: |
| 台湾东北部龟山岛附近热液活动区流体的来源较为复杂, 判断流体来源同时探讨该地区岩浆活动的程度对于龟山岛热液活动研究具有至关重要的意义。通过测定热液流体中的元素浓度和氢氧同位素特征显示: 热液流体的微量元素浓度总体上接近海水值, 但是通过Mg浓度为0 回推得出热液流体的端员组分较为简单, 而且有低Cl?浓度的组分(如地下水)加入, 所测定热液流体中海水特征是由于取样过程中海水混入所致, 氢氧同位素的对应曲线表明热液流体与该地区海水的同位素特征值不一致, 并且不是单一龟山岛上地下淡水来源。龟山岛附近热液流体在氢氧同位素值分布特征上与南胡安得富卡洋脊的深水热液活动流体较为一致。可以初步判断龟山岛附近热液活动流体来源主要由两部分组成:深部物质和龟山岛上的大气降水, 深部的岩浆物质在上升过程中, 发生相分离, 分离相在继续上升的过程中遇到下渗的淡水, 两者混合构成了热液流体的端员组分。因此龟山岛热液活动的出现是由于深部物质活动造成的, 表明目前该地区地壳活动较为活跃。
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| 关键词: 浅海热液活动 龟山岛 热液流体 氢氧同位素 |
| DOI： |
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| 基金项目:中国科学院知识创新工程重要方向项目(KZCX2-YW-211,KZCX3-SW-223); 国家自然科学基金项目(40830849); 国家大洋重大专项课题(DYXM-115-02-1-03) |
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| Origin of the hydrothermal fluid of the shallow sea near Kueishantao Island |
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LIU Chang-hua,WANG Xiao-mei,ZENG Zhi-gang,YIN Xue-bo,CHEN Chen-tung,ZHANG Shu-wei
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| Abstract: |
| Origin of the fluid near Kueishantao Island's hydrothermal activity in northeast Taiwan is complex. To determine fluid's origin and investigate the magmatic activity of this area are very important regarding the hydrothermal activity research of the Kueishantao Island. Measurments of elemental concentrations showed that compositions of the hydrothermal fluid were similar to those of the seawater, indicating contamination by sea water during sampling. Assuming the Mg concentration in the endmember fluid is zero, we calculated the concentrations of other elements in the endmember fluid by correlations analysis, and found that the elemental compositions of the endmember fluid were much simpler than the seawater. In addition, the level of Cl－ was found to lower than the seawater level, suggesting that the mixing of other component with the hydrothermal fluid (e.g. meteoric water). The curve of δ18O-δD showed that the hydrothermal fluid was different from the local seawater in isotopic characteristic values, supporting the idea that, in addition to seawater, meteoric water from Kuishantao Island is also a component of the hydrothermal fluid. The δ18O-δD distribution of hydrothermal fluid near Kuishantao Island is consistent with the south Juan Fuca Ridge fluid. Therefore, we hold the hydrothermal fluid near Kuishantao Island mainly is composed of two parts: the deep portion matter and meteoric water from Kuishantao Island. When the deep magmatic matter rises, the volatile separates from the magma, keeps on rising, and meet and mix with the meteoric water to form the endmember of the hydrothermal fluid. Therefore the appearance of hydrothermal activity near Kuishantao Island is due to the activity of deep magma, indicateing that the local crust is active.
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| Key words: shallow sea hydrothermal activity Kueishantao Island hydrothermal fluid hydrogen oxygen isotope |
