| 大陆俯冲带壳幔相互作用 |
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| 引用本文： | 郑永飞,陈伊翔.大陆俯冲带壳幔相互作用[J].地球科学,2019,44(12):3961-3983. |
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| 作者姓名： | 郑永飞 陈伊翔 |
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| 作者单位： | 1.中国科学院壳幔物质与环境重点实验室, 中国科学技术大学地球和空间科学学院, 安徽合肥 230026 |
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| 基金项目： | 国家“973”计划项目“大陆俯冲带壳幔相互作用”2015CB856106 |
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| 摘 要： | 由板块俯冲引发的深部物质循环过程是地球内部的一级运行机制，主宰了地球从内到外的演化进程，是地球科学研究的重要前沿.俯冲带化学地球动力学研究不仅需要确定俯冲带地壳物质再循环的机制和形式，而且需要确定俯冲带动力来源和热体制及其随时间的变化.为了识别不同类型壳源熔/流体对地幔楔的交代作用、寻求板片-地幔界面反应的岩石学和地球化学证据、理解汇聚板块边缘地壳俯冲和拆沉对地幔不均一性的贡献，我们必须将俯冲带变质作用、交代作用和岩浆作用作为一个地球科学系统来考虑.板块俯冲带变质过程中发生一系列物理化学变化，这些变化不但是导致板块进一步俯冲的主要驱动力，同时也控制着释放的熔/流体组成和俯冲到地球深部的物质组成，对俯冲带化学地球动力学过程产生重要影响.地幔楔作为俯冲系统中连接俯冲盘和仰冲盘的关键构造单元，在地球层圈之间物质循环和能量交换等方面起着重要作用.造山带地幔楔橄榄岩直接记录了俯冲带多种性质的熔/流体交代作用，以及复杂的壳幔物质循环过程.俯冲带岩浆岩是大洋/大陆板块俯冲物质再循环的表现形式，这些岩石样品记录了俯冲带从深部地幔到浅部地壳的过程，也为认识地球深部物质循环提供了理想的天然样品.尽管国际上在俯冲带岩石学和地球化学领域针对地球深部过程的研究方面取得了多项重要进展，但由于研究工作缺乏密切的协同配合，包括俯冲带熔/流体的物理化学性质、俯冲带壳幔相互作用的机制和过程、俯冲带幔源岩浆活动的物质来源和启动机制以及深部地幔过程对地表环境的影响等许多关键科学问题尚未得到根本解决.将来的研究需要聚焦俯冲带物质循环这一核心科学问题，进一步查明俯冲带变质作用、交代作用、岩浆作用等过程的各自特征和相互联系，包括挥发性组分在地球深部的迁移过程及其资源和环境效应，着力考察研究相对薄弱的古俯冲带，阐明板块俯冲与地球深部物质循环之间的耦合机制.
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| 关 键 词： | 大陆俯冲带 俯冲隧道 壳幔相互作用 俯冲带变质作用 俯冲带交代作用 俯冲带岩浆作用 化学地球动力学 |
| 收稿时间： | 2019-10-08 |
Crust-Mantle Interaction in Continental Subduction Zones |
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| Abstract: | The recycling of crustal material into the mantle by subduction is the first-order mechanism of Earth's interior. In order to decipher the crustal-mantle interaction in subduction zones,it is important to distinguish different types of metasomatism by subducting crust-derived fluids such as aqueous solutions and hydrous melts to the mantle wedge. For this purpose,various lines of petrological and geochemical evidence have been used to determine the physicochemical properties of subduction zone fluids at the slab-mantle interface in subduction channels. In doing so,it is critical to determine how crustal rocks underwent metamorphic dehydration and partial melting at mantle depths. After incorporation of subduction zone fluids into the mantle wedge,different compositions of mantle metasomatites were generated in the mantle wedge to result in mantle heterogeneities. As soon as these metasomatites underwent partial melting,mafic igneous rocks were produced with both petrological and geochemical signatures of the subducted crust and the mantle wedge. In this regard,such processes as metamorphism,metasomatism and magmatism in subduction zones are the keys to the recycling of crustal material at convergent plate boundaries. The mantle wedge is the key lithotectonic unit linking the subducting slab and the obducting plate and thus plays an important role in the material transport and energy exchange in the subduction system. The orogenic mantle wedge peridotite directly records different types of crustal metasomatism in subduction zones. Subduction zone magmatism is the manifestation for recycling of subducted oceanic and continental rocks. These rocks witness the processes of magmatic melts from the mantle wedge to crustal levels above subduction zones,providing the natural samples to decode indirectly the crustal recycling at convergent plate boundaries. Although there are many advances in the study of subduction zones with respect to the crust-mantle interaction,such three processes as metamorphism,metasomatism and magmatism in subduction zones are still the most important targets in the deep Earth science. Many key problems cannot be resolved if no sufficient attention is paid to an integrated study of these three aspects. Such problems include the physiochemical properties of subduction zone fluids,the mechanism and process of crust-mantle interaction,the material source and triggering mechanism of mantle-derived magmatism above subduction zones,and the impact of deep mantle process on the shallow crustal environments. The future research needs to focus on the key question of material recycling in subduction zones,and take the metamorphism,metasomatism and magmatism in subduction zones as a whole in the framework of Earth system science. This concerns the transport process and the resource and environmental effects of volatile components,and clarify the coupling mechanism of plate subduction and material recycling in deep Earth by intensive studies of paleo-subduction zones. |
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