| 动高压物理在地球与行星科学研究中的应用 |
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| 引用本文： | 毕延,经福谦.动高压物理在地球与行星科学研究中的应用[J].地学前缘,2005,12(1):79-92. |
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| 作者姓名： | 毕延 经福谦 |
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| 作者单位： | 中国工程物理研究院,流体物理研究所,冲击波物理与爆轰物理重点实验室,四川,绵阳,621900 |
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| 摘 要： | 综述了动高压物理应用于地球和行星科学研究中的一些最新进展,包括地球内部的物质组成与热力学状态,巨行星的物质组成模型,太阳系中的碰撞成坑与吸积相互作用等。依据铁的冲击波数据,结合其他热力学数据,可以得到一条统一的铁的熔化曲线,将动高压与静高压数据完全统一,初步解决了长期困扰高压界的动、静压关于铁的熔化温度存在系统偏差的诘难。外推到ICB处(330 GPa),铁的熔化温度(亦称锚定温度)约为(5 950±100) K。冲击Hugoniot 数据,结合地震学模型可以约束地幔与地核的物质组成。冲击压缩下钙钛矿型(Mg0 9,Fe0 1)SiO3的高压声速测量结果表明,1 770 km深度的不连续面不仅是一个相变界面而且是一个化学成分或矿物学分界面。低温可凝聚气体(H2、He)或冰(H2 O, CH4, CO2, NH3 和N2 )的冲击波数据,及Jeffrey 数等其他数据可以用来构建巨行星(如木星和土星)的物质组成模型。地球深部矿物的冲击温度测量可以用来研究它们的高压熔化行为,据此建立的高压相图可以为控制地幔对流的地幔物质的准静态蠕变提供约束条件。熔融硅酸盐在上地幔压力条件下的冲击压缩数据,可以约束地幔熔岩稳定存在的深度,在此深度地幔熔岩不会因固体围岩提供的浮力而向上运移到地表,从而在此深度形成稳定的低速带。冲击波数据在描写行?
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| 关 键 词： | 内核边界处铁的熔化温度(锚定温度) 1770km深处的成分不连续面 下地幔中的热异常 核幔边界 地球原始大气的形成 巨行星的物质组分模型 行星表面的大型撞击 KT(白垩纪—第三纪)界面的大规模灭绝事件 |
| 文章编号： | 1005-2321(2005)01-079-14 |
| 修稿时间： | 2004年12月21 |
Application of dynamic high-pressure physics to Earth and Planetary Science studies |
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| BI Yan,JING Fu-qian.Application of dynamic high-pressure physics to Earth and Planetary Science studies[J].Earth Science Frontiers,2005,12(1):79-92. |
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| Authors: | BI Yan JING Fu-qian |
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| Abstract: | In this paper, the recent achievements of dynamic high-pressure physics applied to Earth and Planetary Sciences are reviewed. This includes the state and composition of Earth's interior, the compositional models of major planets, and processes of impacting, cratering and accreting in the solar system. Shock wave data for iron, combined with other thermodynamic data, yield a uniform melting curve of iron for both dynamic and static high pressure data. The data also indicate that the melting temperature of iron at the inner core boundary (ICB),or the anchor temperature, is about (5 950±100) K. Shock Hugoniot data, in conjuction with seismological models of the Earth, yield constraints on the composition of the Earth’s mantle and core. The sound velocity measurements for silicate such as (Mg_(0.9),Fe_(0.1))SiO_(3 )(perovskite) under shock compression imply that the discontinuity at the depth of 1 770 km is not only a phase transition boundary but also a compositional boundary. Whereas, the shock data and other similar data for low temperature condensable gases (H_2,He) and ices (H_2O, CH_(4), CO_2, NH_3, and N_2), combined with solar elements abundance and Jeffrey's number data, have been used to construct compositional models of the major planets (e. g., Jupiter and Saturn). Shock temperature measurements of the possible minerals in the Earth's interior could be applied to investigate their melting behaviors, with which high pressures phase diagrams could be constructed. This would provide constraints to the quasi-static creep rheology of the mantle that controls convection. Shock compression of molten silicates at upper mantle pressures provides constraints on the depths in the mantle from which melts can reach the surface. Application of shock wave data is critical to describe the energy partitioning upon hypervelocity impacts on planetary surfaces. These data permit calculation of the melt and vapor produced by impactors as a function of impact velocity, and provide a quantitative basis for determining the impact-induced melting of near-surface water ice on Mars. Shock induced devolatilization during the impact processes can also be described using shock wave and other thermodynamic data, and can be used to model the formation of Earth's primitive atmosphere. Furthermore, giant impacts upon the Earth's surface could release abundant gases, such as CO_(2 )and SO_(2 )into the atmosphere that strongly affect the global climate, which appears to have played a major role in the evolution and extinction of species during the Earth's history. |
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| Keywords: | melting temperature of iron at ICB (anchor temperature) compositional discontinuity at the depth of 1 770 km thermal heterogeneity in lower mantle CMB formation of Earth's primitive atmosphere compositional models of major planets giant |
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