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1.
大陆俯冲化学地球动力学 总被引:9,自引:2,他引:7
详细介绍了本世纪60年代以来高温高压条件下岩石弹性波速度测量的发展历史,重点介绍了高温高压条件下岩石弹性波速测量的基本原理和有代表性的三个研究小组(德国Christian Albrechts大学Kern领导的研究小组,美国威斯康星大学Christensen领导的研究小组,中国科学院地球化学研究所谢鸿森领导的研究小组)采用的实验方法,举例说明了高温高压条件下岩石弹性波速测量在推测深部地质过程和构筑区域岩石圈结构及物质组成模型方面的应用。 相似文献
2.
“地球深部物质弹性的实验研究”是1989年国家自然科学基金资助项目(编号:48970206)。在实验室模拟地球内部的高温高压条件下,对矿物岩石进行就位弹性波速测量是开展本项目研究的主要方法。由于实验技术难度大,到目前为止已发表的较系统的高压波速测量的数据大多是在室温下获得的,压力范围多在1.0GPa以下。为了提高弹性波速测量的压力和温度范围,获得与地球内部物质更接近的弹性波速的实验数据。三年来该课题组全力以赴,首先对原有的YJ—3000吨压力机的静态超高压大腔体实验设备进行了技术改造。使其温度、压力控制系统实现了自动化,大大改善了升降压、升降温过程中高压腔体的压力温度品质。在此基础上,根据自己实验设备的特点,设计和安装了高温超高压超声脉冲法波速测量装置和样品组装方式。经过反复实验和改进,获得了高压同时加热条件下清晰的超声波图形。并将全波震相分析理论应用于图形的识 相似文献
3.
地球深部物质科学——在静高压大腔体实验研究方面的某些进展 总被引:1,自引:0,他引:1
介绍近年来使用静态超高压大腔体实验技术 ,在模拟地球内部的高温高压条件下 ,对地球物质进行的若干物理和化学性质的实验研究。高压同时高温条件下多种岩石样品的弹性波速就位测量揭示出物质的声软化现象和振幅效应 ;高温高压下陨石和岩石的熔融结晶实验发现了陨石硅酸盐相的不混溶现象以及玄武岩熔体结构的变化 ,在玄武岩转变为榴辉岩的实验中观测到了刚玉相 ;在高温高压水的实验中 ,发现了冰 Ⅶ 的亚稳相和熔融前效应以及超临界水及其稀溶液的一些新性质。这些实验结果为探索地球深部物质的性质和状态以及迁移和演化提供了新的依据。 相似文献
4.
地幔矿物的波速测量研究是认识地球深部物质组成和性质的重要方法.国际上在大压机中利用超声波技术对地幔矿物材料开展了广泛的波速测量研究,实验温压范围达到地幔转换带条件,而国内大压机超声波波速测量局限于6 GPa压力以内.在中国地质大学(武汉)地球深部研究实验室1 000 t Walker型多面砧大压机上,利用超声波技术,建立了一套高压波速测量系统,对地幔转换带矿物Mg2SiO4瓦兹利石多晶样品在18 GPa压力范围内的弹性波速进行了测量,测量结果与前人超声波波速测量结果相比总体吻合程度良好.利用多面砧大压机和超声波技术,在国内首次实现了地幔转换带高压条件下的波速测量,缩短了我国高压波速测量水平与国外先进水平的差距,同时可以为中国及周边地区地球物理观测资料的解析提供矿物物理方面的实验约束,为国内岩石矿物和固体材料的弹性研究提供实验技术支持. 相似文献
5.
实验矿物物理是高温高压实验地球科学的重要分支学科之一,它主要是通过高温高压实验模拟地球内部的物理化学环境,并原位测定地球深部物质(矿物、岩石和熔/流体等)的相变和状态方程、电导率、热导率等物理参数,探讨地球内部的圈层结构、物质组成、地球动力学过程等地球物理性质相关的一系列重要科学问题. 综述了实验矿物物理的发展历史、近二十年的研究现状与趋势,并展望了该学科未来发展的方向、关键科学问题与面临的主要挑战. 相似文献
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7.
高温高压微束衍射实验进展及其地学应用 总被引:6,自引:6,他引:6
同步辐射X射线微束衍射技术与静态高压装置(包括金刚石压砧设备和大腔体压力机设备)结合运用是研究高温高压下物质晶体结构、相变等的有效方法。金刚石压砧高温高压实验技术的发展体现在:在产生极端高温高压的同时,获得准确的实验温度压力值,采用充装气体传压介质等方法减小压力梯度,采用激光双面加温技术和改进激光光路以减小样品径向和轴向的温度梯度。大腔体压力机高温高压实验技术的发展主要表现在产生更高的实验压力,以及测试过程中使样品在一定幅度摆动以消除晶体生长和择优取向对衍射数据的影响。同步辐射X射线微束衍射技术的发展主要表现在更高亮度和更宽能量范围的同步辐射光源的使用、X射线聚焦技术的发展,以及角色散X射线衍射测试技术的进步。介绍了近年来高温高压微束衍射实验在地球科学领域所取得的一些最新进展,包括硅酸盐超钙钛矿的实验发现,铁的高温高压相变及熔融曲线、SiO2 超斯石英相变、橄榄石尖晶石相—超尖晶石相转变压力的精确测定等研究结果;认为硅酸盐超钙钛矿的进一步深入研究,水对地球深部矿物岩石力学性质及熔融行为的影响,高温高压下物质的化学反应性和地球深部元素的地球化学行为等,是今后高温高压实验研究的重要方向。 相似文献
8.
高温高压实验作为地球科学研究的重要方向之一,通过模拟地球深部的温度和压力条件,了解地球深部物质的物理化学性质、地球内部结构和动力学演化。角闪石属于双链硅酸盐矿物,为地幔岩石圈的重要组成,广泛分布在海洋地壳、俯冲板块、变质岩和火成岩中。作为俯冲带的重要含水矿物,角闪石的广泛分布和高温高压下的脱水对于理解俯冲带水含量以及水迁移具有重要作用,同时在俯冲带的地震活动、高电导率异常、地震波速异常和岩浆活动中扮演重要角色。在过去的近百年时间里,国内外学者对角闪石高温高压物理化学性质进行了大量的研究。角闪石具有非常复杂的元素组成和结构特征,由此也导致了不同角闪石物理化学性质存在显著不同,包括脱水与脱羟基反应中元素迁移的差异、角闪石形成与分解过程中碱性元素(K+Na)和H2O含量对热稳定的影响、不同空间群结构下的高压结构相变、原位条件下不同结晶方向的电导率异常、不同结晶学优选方位(CPO)下的波速异常等。已有的研究对于角闪石的物理化学性质以及其在俯冲带中发挥的作用有了比较清楚的认识,但仍然有许多问题需要进一步研究,如角闪石的高压脱水动力学、热物性和变形机制等。 相似文献
9.
高温高压变形实验是研究地球深部组成矿物流变学性质的重要技术手段之一.D-DIA(deformation-DIA)装置是最近10年来兴起的一种新的高温高压变形实验设备,通常可实现的最高压力为15 GPa和温度约为2 000 K;而同步辐射X射线衍射已经广泛地应用到物质结构科学的研究中,二者相结合,能够有效原位地研究材料物质在高温高压下的流变学性质.以美国布鲁克海文国家实验室配合有同步辐射源的D-DIA装置为例,介绍该装置的基本结构、工作原理及D-DIA装置与X射线结合技术如何实现矿物高温高压下变形过程的原位观测及相关定量力学数据的获取.这一技术突破了传统流变仪的压力局限,为在更高压力(P>4 GPa)条件下研究地球深部组成物质的高温高压流变学性质提供了有效途径. 相似文献
10.
同步辐射激光加温DAC技术及在地球深部物质研究中的应用 总被引:1,自引:1,他引:0
实验室模拟地球深部的温度和压力环境,研究地球相关材料的物理和化学性质,是解释地震波数据、进一步了解地球内部结构和动力学过程的重要途径。用高功率的红外激光光束,加温金刚石对顶砧压腔(DAC)中的样品,可以获得深部地幔乃至地核的极端温度和压力条件,已广泛地用于地球深部矿物的相变、熔融和状态方程研究。同步辐射微束技术的发展,为激光加温DAC技术的应用开辟了新的领域,也使地幔及地核条件下的矿物研究有了重要的突破。文章介绍激光加温DAC技术的发展;阐述高温高压原位的同步辐射X射线衍射方法;例举激光加温DAC技术在地球深部物质研究中的一些应用;并对一些关键的技术问题加以分析和讨论。 相似文献
11.
L. Vočadlo K. S. Knight G. D. Price I. G. Wood 《Physics and Chemistry of Minerals》2002,29(2):132-139
The thermal expansion and crystal structure of FeSi has been determined by neutron powder diffraction between 4 and 1173?K. No evidence was seen of any structural or magnetic transitions at low temperatures. The average volumetric thermal expansion coefficient above room temperature was found to be 4.85(5)?×?10?5?K?1. The cell volume was fitted over the complete temperature range using Grüneisen approximations to the zero pressure equation of state, with the internal energy calculated via a Debye model; a Grüneisen second-order approximation gave the following parameters: θD=445(11)?K, V 0=89.596(8)?Å3, K 0′=4.4(4) and γ′=2.33(3), where θD is the Debye temperature, V 0 is V at T=0?K, K 0′ is the first derivative with respect to pressure of the incompressibility and γ′ is a Grüneisen parameter. The thermodynamic Grüneisen parameter, γth, has been calculated from experimental data in the range 4–400?K. The crystal structure was found to be almost invariant with temperature. The thermal vibrations of the Fe atoms are almost isotropic at all temperatures; those of the Si atoms become more anisotropic as the temperature increases. 相似文献
12.
Michael H. G. Jacobs Rainer Schmid-Fetzer Arie P. van den Berg 《Physics and Chemistry of Minerals》2013,40(3):207-227
We use Kieffer’s model to represent the vibrational density of states (VDoS) and thermodynamic properties of pure substances in pressure–temperature space. We show that this model can be simplified to a vibrational model in which the VDoS is represented by multiple Einstein frequencies without significant loss of accuracy in thermodynamic properties relative to experimental data. The resulting analytical expressions for thermodynamic properties, including the Gibbs energy, are mathematically simple and easily accommodated in existing computational software for making thermodynamic databases. We show for aluminium, platinum, orthoenstatite and forsterite that thermodynamic properties can be represented with comparable accuracy as with Kieffer’s model with the same number of fitting parameters as in the Mie–Grüneisen–Debye model. We demonstrate that the method enables to achieve thermodynamic properties with superior accuracy relative to the Mie–Grüneisen–Debye method. The method is versatile in the sense that it allows incorporating dispersion of Grüneisen parameters. It is possible to extend the formalism to include other physical effects, such as intrinsic anharmonicity in the same way as in vibrational models based on Kieffer’s formalism. 相似文献
13.
The Raman spectra of bixbyite, Mn2O3, were measured up to 40 GPa at room temperature. Mn2O3 undergoes a phase transition from the C-type rare earth structure to the CaIrO3-type (post-perovskite) structure at 16–25 GPa. The transition pressure measured in Raman spectroscopy is significantly lower
than the pressure reported previously by an X-ray diffraction study. This could be due to the greater polarizability in the
CaIrO3-type structure, consistent with high-pressure observation on the CaIrO3 type in MgGeO3, although it is still possible that experimental differences may cause the discrepancy. Unlike the change at the perovskite
to CaIrO3-type transition, the spectroscopic Grüneisen parameter does not decrease at the C-type to CaIrO3-type transition. The spectroscopic Grüneisen parameter of the low-pressure phase (C type) is significantly lower than thermodynamic
Grüneisen parameter, suggesting significant magnetic contributions to the thermodynamic property of this material. Our Raman
measurements on CaIrO3-type Mn2O3 contribute to building systematic knowledge about this structure, which has emerged as one of the common structures found
in geophysically important materials. 相似文献
14.
The single crystal elastic constants of nonmetamict zircons have been measured as a function of pressure to 12 kb at room temperature and also as a function of temperature between 25 and 300° C at atmospheric pressure. The pressure derivatives of the elastic constants are: C 11=10.78, C 33=5.88, C 44=0.99, C 66=?0.31, C 12=3.24, C 13=6.20. The anomalous negative behaviour of C 66 versus pressure could be associated with a high pressure phase transition. The pressure and temperature derivatives of the isotropic elastic wave velocities and elastic moduli for nonmetamict zircon are calculated from the present single crystal data by the Voigt, Ruess, and Hill approximations and compared with the values of some other oxides and silicates. The pressure derivative of the isotropic adiabatic bulk modulus is relatively high (dK S/dP=6.50), and the pressure derivative of the shear modulus is relatively low, (dG/dP=0.78), compared to the corresponding values for some other oxides and silicates. The Debye temperature, ?D, and the high temperature limit of the Grüneisen parameter, γHt, calculated from the elastic constants and their pressure derivatives, agrees well with the Debye temperature and the thermal Grüneisen parameter, γth, calculated from the thermal expansion, heat capacity, and compressibility data. 相似文献
15.
Orson L. Anderson 《Physics and Chemistry of Minerals》1979,5(1):33-51
The Hildebrand thermal equation of state (EOS) is revived and applied to minerals appropriate to the earth's interior. The chief virtue of this EOS is that it escapes the necessity of evaluating a Grüneisen parameter at high compression and high temperature. The classical Grüneisen parameter is replaced by the product of two experimentally measured parameters: α, the coefficient of thermal expansivity, and K T , the isothermal bulk modulus. In order for the Hildebrand EOS to be useful in geophysical conditions it is necessary to show that α K T is, to a large extent, independent of volume. This can be done directly by experiment, following Yagi, or indirectly using thermodynamic formulae where other measurements are used in place of α K T . Four such tests are proposed, two of them following tests proposed by Swenson. The result indicates that most, if not all, of the close-packed minerals relevant to geophysics follow the rule that the value of α K T is to a satisfactory extent independent of compression. 相似文献
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The lattice parameter of magnesiowüstite (Mg0.6Fe0.4)O has been measured up to a pressure of 30 GPa and a temperature of 800 K, using an external heated diamond anvil cell and diffraction using X-rays from a synchrotron source. The experiments were conducted under quasi-hydrostatic condition, using neon as a pressure transmitting medium. The experimental P-V-T data were fitted to a thermal-pressure model with the isothermal bulk modulus at room temperature K T0 = 157 GPa, (?K TO /?P) T =4, (?K T /?T) P =-2.7(3) × 10-2 GPa/K, (?K T /?T) v =-0.2(2) × 10-2 GPa/K and the Anderson-Grüneisen parameter δ T =4.3(5) above the Debye temperature. The data were also fitted to the Mie-Grüneisen thermal equation of state. The least-squares fit yields the Debye temperature θ DO = 500(20) K, the Grüneisen parameter γ 0=1.50(5), and the volume dependence q=1.1(5). Both thermal-pressure models give consistent P-V-T relations for magnesiowüstite to 140 GPa and 4000 K. The P-V-T relations for magnesiowüstite were also calculate by using a modified high-temperature Birch-Murnaghan equation of state with a δ t of 4.3. The results are consistent with those calculated by using the thermal-pressure model and the Mie-Grüneisen relation to 140 GPa and 3000 K. 相似文献
18.
In situ impedance spectroscopy in laboratory experiments at high pressure and temperature can provide crucial quantitative
information on properties of rock materials at depth as well as on physical and chemical processes occurring in the deep Earth.
We developed an experimental setup for in situ electrical impedance measurements in a piston-cylinder apparatus and applied
it to study the kinetics of charge carriers and phase transformations in pyrophyllite and CaCO3 aggregates. From comparison with previous studies, we found that absolute values of electrical conductivity and pressure–temperature
conditions for dehydration reactions in pyrophyllite and phase transformations in CaCO3 can be accurately determined using our setup. Dehydration of pyrophyllite significantly enhances the transport kinetics and
the effect is more pronounced under undrained conditions than under drained conditions. When dehydroxylation and decomposition
temperatures for pyrophyllite under undrained and drained conditions are combined, they appear independent of pressure rather
than increasing with pressure as previously suggested. Electrical conductivity of CaCO3 varies with impurity content and grain size, and is most likely controlled by diffusion of oxygen along wet grain boundaries.
When applied to the Earth, the results on pyrophyllite suggest that the increase in electrical conductivity in rocks that
undergo dehydration should be taken into account in interpreting magnetotelluric surveys of regions with anomalously high
conductivity found above subducting plates. The results on CaCO3 indicate that grain boundary transport controls the electrical conductivity in fine-grained calcite rocks; hence calcite
mylonites may be detected using magnetotelluric methods. Order–disorder transformations, such as occurring in calcite, possibly
affect the physical properties of rocks (e.g., rheology) by changing the kinetics of atomistic transport processes. 相似文献
19.
In the Pötürge (Malatya, Turkey) area pyrophyllite occurrences are common in the shear zones, mostly in the form of lenses along faults. Mineralogical investigations (XRD, FTIR and SEM) revealed that pyrophyllite, kaolinite (dickite) and quartz are present in the form of major phases and muscovite (sericite), kyanite, chlorite, and alunite are only present in the form of minor phases. This study revealed that the existence of the kyanite phase points out to high pressure and temperature conditions which the rocks were underwent. On the other hand, the minerals such as pyrophyllite, kaolinite, and alunite are products of a low degree metamorphism (retrograde). The mineral paragenesis in the pyrophyllite deposits suggests that the formation of minerals took place in two ways: (1) the transformation of kyanite into pyrophyllite and quartz through retrograde metamorphism by a high degree temperature, (2) then pyrophyllite and probably muscovite were transformed into kaolinite and alunite through reactions with relatively low temperature hydrothermal fluids. The geochemical data indicate that during the retrograde metamorphism the elements K, Rb, Sr, Ba, S, and Fe were mobile, the elements Si, Al, P moderately mobile to immobile and the HPS elements (Zr, Ti, and Nb) were immobile. It was shown that the formation of pyrophyllite, kaolinite and alunite was associated with depletion in alkalis, Mg, Fe and enrichment of elements including Sr, Ba, and S. Mineralogical and geochemical data suggest that parent rocks (pre-metamorphism) of the Pötürge pyrophyllite were probably kaolinite, Al-rich clays or bauxites. 相似文献
20.
Using a Fizeau interferometry technique, we have measured the coefficients of linear thermal expansion of single-crystal forsterite (Mg2SiO4) along three axial directions to 1023 K during heating and cooling cycles. Overall, the present data are consistent in magnitude (within 1 to 2%) with those previously reported but have less scatter. We used the Grüneisen statistical mechanical approach in analzying the data. The least-squares method was applied to evaluate thermal parameters (?, Q 0, k and a) in two cases. The expansion coefficients in wider temperature ranges were extrapolated by using the parameters of solution 2 (i.e., solution by fixing ? and k). In contrast to earlier findings, our results show that for forsterite the Grüneisen parameter decreases with temperature, implying that it does not behave too differently from fayalite (Fe2SiO4) and periclase (MgO). 相似文献