| 超高压变质带的全球分布及其大地构造意义 |
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| 引用本文： | 游振东.超高压变质带的全球分布及其大地构造意义[J].高校地质学报,2007,13(3):383-391. |
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| 作者姓名： | 游振东 |
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| 作者单位： | 中国地质大学（武汉），武汉 430074 |
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| 基金项目： | 国家重点基础研究发展计划(973计划)
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国家自然科学基金 |
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| 摘 要： | 对全球28个超高压变质岩产地的地质对比研究发现，超高压变质带的发育，与弧-陆和陆-陆碰撞造山带关系密切。碰撞造山带多发育于活动的大陆边缘。在那里，冷的陆壳物质可以深俯冲到另一个相对稳定的未俯冲的板块之下，其深度可以超过90~120 km，在高压达>2.5 GPa和温度约600℃或更高条件下，导致超高压特征矿物如，柯石英、金刚石等的生成。在空间分布上，超高压变质带集中于欧亚大陆及其周缘，澳洲和北美目前尚未有报道。从时代上看，超高压变质带多出现于显生宙，前寒武纪只有晚元古代（泛非运动期）少数两例。说明以超高压变质带为特征的碰撞造山作用，是显生宙以来，陆壳增生达到一定的规模后，才出现的构造体制；Rodinia和Pangea古大陆的裂解，使地温梯度降低，从而有利于超高压变质带的生成。
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| 关 键 词： | 超高压变质岩 碰撞造山带 深俯冲作用 构造体制 地温梯度 |
| 文章编号： | 1006-7493（2007）03-0383-09 |
| 收稿时间： | 2007-09-20 |
| 修稿时间： | 2007-04-05 |
Global Distribution of Ultrahigh-Pressure Metamorphic Belts and Its Geotectonic Significance |
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| YOU Zhen-dong.Global Distribution of Ultrahigh-Pressure Metamorphic Belts and Its Geotectonic Significance[J].Geological Journal of China Universities,2007,13(3):383-391. |
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| Authors: | YOU Zhen-dong |
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| Institution: | China University of Geosciences, Wuhan 430074, China |
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| Abstract: | On the basis of geological studies of some 28 localities of Ultrahigh-Pressure Metamorphic (UHPM) rocks all over the world it is not difficult to find that most UHPM belts are developed in close relationship with the island arc-continent and the continent-continent collisional orogenic belts. Majority of them are developed within the active continental margins where cold continental materials can be subducted deeply under another relatively
stable or non-subducted plate, and the subduction depth of which can exceed 90~120 km. Consequently, under the deep-seated high-pressure (>2.5 Gpa) and high-temperature (c. 600℃ or higher) in combination with other favorable metamorphic conditions the UHP typomorphic minerals，such as coesite and diamond, can be formed. According to present data UHPM rocks are spatially concentrated within Eurasia and at its margins. However, there is still lack
of information for North America and Australia. Temporally the UHPM rocks are usually Phaenerozoic in age. The Precambrian UHPM belts are few, only two of them are Neoproterozoic in age (Pan-African stage). It is suggested that the collisional orogenic process with UHP metamorphism be a tectonic regime when accretion of the continental crust reaches considerable thickneses. The statistics of temporal distribution of UHPM belts shows two maxima at
Paleozoic and Mesozoic-Cenozoic, respectively. It indicates that the break-up of Rodinia and Pangea caused the lowering of geothermal gradient of the continental crust which is favorable for formation of the UHPM belts. |
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| Keywords: | ultrahigh-pressure metamorphic rocks collisional orogenic belt deep subduction tectonic regime low geothermal gradient |
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