| 高压-超高压变质岩石中石榴石的环带和成因 |
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| 引用本文： | 夏琼霞,郑永飞.高压-超高压变质岩石中石榴石的环带和成因[J].岩石学报,2011,27(2):433-450. |
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| 作者姓名： | 夏琼霞 郑永飞 |
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| 作者单位： | 中国科学技术大学地球和空间科学学院,中国科学院壳幔物质与环境重点实验室,合肥,230026 |
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| 基金项目： | 本文受国家973项目(2009CB825004)和国家自然科学基金项目(40921002、41003014)联合资助. |
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| 摘 要： | 在俯冲带变质过程中,石榴石是高压-超高压变质榴辉岩和片麻岩的常见变质矿物。由于石榴石具有难熔和流体中的低溶解能力的特点,通常可以很好地保存下来,并且能够保留复杂的化学成分环带,以及不同类型的矿物或流体包裹体,为解释石榴石寄主岩石经历的变质演化历史提供了重要信息。石榴子石的主微量元素成分受控于很多因素,如全岩成分、变质的温压条件、控制石榴子石形成的相关变质反应、与石榴子石共生的矿物种类和成分等。因此,在利用石榴石探讨超高压变质的演化历史时,对石榴石进行系统的主要元素、微量元素、氧同位素以及矿物包裹体分析,以及相互间的成因关系。同时,对石榴石中的锆石或独居石包裹体并进行原位U-Pb定年和微量元素分析,可以为变质石榴石的形成时代提供直接的时间制约。深入研究超高压变质岩中石榴石的生长阶段,不仅可以为含石榴石寄主岩石的变质过程提供岩石学和地球化学证据,而且对于理解石榴石的形成机制、生长规律及其变质化学动力学过程具有重要的科学意义。
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| 关 键 词： | 石榴石 高压/超高压变质 成因机制 环带 包裹体 |
| 收稿时间： | 2010/11/10 0:00:00 |
| 修稿时间： | 1/6/2011 12:00:00 AM |
The composition and chemical zoning in garnet from high to ultrahigh pressure metamorphic rocks |
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| XIA QiongXia and ZHENG YongFei.The composition and chemical zoning in garnet from high to ultrahigh pressure metamorphic rocks[J].Acta Petrologica Sinica,2011,27(2):433-450. |
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| Authors: | XIA QiongXia and ZHENG YongFei |
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| Institution: | CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China |
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| Abstract: | Garnet is common in eclogite and gneiss of high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic origin. It can be well preserved during subduction-zone metamorphism for its high refractoriness and low solubility in fluid and melt. The chemical composition and mineral inclusions preserved in garnet can be used to constrain the P-T conditions, metamorphic evolution, and fluid action. The chemical composition of garnet is related to many factors, such as whole-rock composition, P-T conditions, garnet-forming metamorphic reactions and the assemblage of coexisting minerals. Thus the major elements, trace elements, oxygen isotopes, mineral inclusions and their relations in garnet should all be taken into account when it is used to constrain the metamorphic P-T evolution in UHP metamorphic rocks. In addition, in-situ analyses of U-Pb isotopes and trace elements in accessory minerals such as zircon and/or monazite inclusions in garnet can place a direct constraint on the time of metamorphic garnet growth. Through studying the history of garnet growth during subduction-zone metamorphism, it can not only provide petrologic and geochemical evidence for the processes to produce garnet-bearing metamorphic rocks, but also give clues to the origin of garnet. These are very important to the chemical dynamics of subduction-zone metamorphism. |
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| Keywords: | Garnet HP/UHP metamorphism Origin Chemical zoning Inclusions |
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