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1.
本文提出一种利用磁异常失量倾角这个参量对二度磁异常作定量解释的方法。矢量倾角是Ta(由Za、Ha所合成)与测线所夹的角度,其特征可以由其正切即Za/Ha值所反映。 相似文献
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异构比φiC4 /φnC4 和φiC5 /φnC5 的石油地质意义 总被引：6，自引：1，他引：6
同分子量的正构烷烃和异构烷烃存在着物理化学性质差异,在运移过程中受围岩的物理化学性质及其它外部因素的影响必然产生分异效应,从而使二者在空间分布上具有一定的特征和规律,异构比指标可以在一定程度上反映出这种特征和规律性。用异构比φiC4 /φnC4 和φiC5 /φnC5 指标可以判断有机质的成熟度,研究轻烃运移的途径、方向、生成环境及轻烃的生物降解。 相似文献
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Steeve Gréaux Yoshio Kono Norimasa Nishiyama Takehiro Kunimoto Kouhei Wada Tetsuo Irifune 《Physics and Chemistry of Minerals》2011,38(2):85-94
The thermoelastic parameters of synthetic Ca3Al2Si3O12 grossular garnet were examined in situ at high-pressure and high-temperature by energy dispersive X-ray diffraction, using
a Kawai-type multi-anvil press apparatus coupled with synchrotron radiation. Measurements have been conducted at pressures
up to 20 GPa and temperatures up to 1,650 K: this P, T range covered the entire high-P, T stability field of grossular garnet. The analysis of room temperature data yielded V
0,300 = 1,664 ± 2 ?3 and K
0 = 166 ± 3 GPa for K￠0 K^{\prime}_{0} fixed to 4.0. Fitting of our P–V–T data by means of the high-temperature third order Birch–Murnaghan or the Mie–Grüneisen–Debye thermal equations of state,
gives the thermoelastic parameters: (∂K
0,T
/∂T)
P
= −0.019 ± 0.001 GPa K−1 and α
0,T
= 2.62 ± 0.23 × 10−5 K−1, or γ
0 = 1.21 for fixed values q
0 = 1.0 and θ
0 = 823 (Isaak et al. Phys Chem Min19:106–120, 1992). From the comparison of fits from two different approaches, we propose to constrain the bulk modulus of grossular garnet
and its pressure derivative to K
T0 = 166 GPa and K￠T0 K^{\prime}_{T0} = 4.03–4.35. Present results are compared with previously determined thermoelastic properties of grossular-rich garnets. 相似文献
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An olivine grain from a peridotite nodule 9206 (Udachnaya kimberlite, Siberia) was investigated by TEM methods including
AEM, HRTEM, SAED and EELS techniques. A previous study of the 9206 olivine sample revealed OH absorption bands in the IR spectrum
and abundant nanometer-sized OH-bearing inclusions, of hexagonal-like or lamellar shape. Inclusions, which are several hundred
nm in size, consist of 10 ? phase, talc and serpentine (chrysotile and lizardite). The lamellar (LI) and hexagon-like small
inclusions of several ten nm in size (SI) are the topic of the present paper. AEM investigations of the inclusions reveal
Mg, Fe and Si as cations only. The Mg/Si and Fe/Si atomic ratios are lower in the inclusions than in the host olivine. The
Si concentration in the olivine host and both lamellar inclusions and small inclusions is the same. A pre-peak at 528eV was
observed in EEL spectra of LI and SI, which is attributed to OH− or Fe3+. From these data it is concluded that there is a OH−- or Fe3+-bearing cation-deficient olivine-like phase present.
HRTEM lattice fringe images of LI and SI exhibit modulated band-like contrasts, which are superimposed onto the olivine lattice.
Diffraction patterns (Fourier-transforms) of the HREM images as well as SAED patterns show that the band-like contrasts in
HRTEM images of the inclusions are caused by periodic modulations of the olivine lattice. Three kinds of superperiodicity
in the olivine structure such as 2a, 3a and 3c, were observed in SAED patterns. The corresponding olivine supercells labelled
here as Hy-2a, Hy-3a and Hy-3c were derived. The M1-vacancies located in the (100) and (001) octahedral layers of the olivine
lattice are suggested to form ordered arrays of planar defects (PD), which cause the band-like contrasts in HRTEM patterns
as well as the superperiodicity in the SAED patterns.
The vacancy concentrations as well as the chemical composition of Hy-2a, Hy-3a and Hy-3c olivine supercells were calculated
using crystal chemical approaches, assuming either {(OH)<
O−V"
Me−(OH)<
O}↔, or {F
e
<
Fe
−H
Me
′}↔ or {2F
e
<
Fe
−V
Me
"}↔ point defect associates. The calculated theoretical compositions Mg1.615Fe+2
0.135v0.25SiO4H0.5 (Hy-2a) and Mg1.54Fe2+
0.12v0.33SiO4H0.66 (Hy-3a and Hy-3c) are in a good agreement with the AEM data on inclusions. Hy-2a, Hy-3a and Hy-3c are considered to be a
hydrous olivine with the extended chemical formula (Mg1-yFe2+
y)2−xvxSiO4H2x. The crystal structure of hydrous olivine is proposed to be a modular olivine structure with Mg-vacant modules. The crystal
chemical formula of hydrous olivines in terms of a modular structure can be written as [MgSiO4H2] · 3[Mg1.82Fe0.18SiO4] for Hy-2a, [MgSiO4H2] · 2[Mg1.82Fe0.18SiO4] for Hy-3a and Hy-3c.
Hydrous olivine is suggested to be exsolved from the olivine 9206, which has been initially saturated by OH-bearing point
defects. The olivine 9206 hydration as well as the following exsolution of hydrous olivine inclusions is suggested to occur
at high pressure-high temperature conditions of the upper mantle.
Received: 15 January 2001 / Accepted: 2 July 2001 相似文献
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《地质学刊》2005,29(1):32-36
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Mario Tribaudino Fabrizio Nestola Marco Bruno Tiziana Boffa Ballaran Christian Liebske 《Physics and Chemistry of Minerals》2008,35(5):241-248
The high temperature volume and axial parameters for six C2/c clinopyroxenes along the NaAlSi2O6–NaFe3+Si2O6 and NaAlSi2O6–CaFe2+Si2O6 joins were determined from room T up to 800°C, using integrated diffraction profiles from in situ high temperature single crystal data collections. The thermal
expansion coefficient was determined by fitting the experimental data according to the relation: ln(V/V
0) = α(T − T
0). The thermal expansion coefficient increases by about 15% along the jadeite–hedenbergite join, whereas it is almost constant
between jadeite and aegirine. The increase is related to the Ca for Na substitution into the M2 site; the same behaviour was
observed along the jadeite–diopside solid solution, which presents the same substitution at the M2 site. Strain tensor analysis
shows that the major deformation with temperature occurs in all samples along the b axis; on the (010) plane the higher deformation occurs in jadeite and aegirine at a direction almost normal to the tetrahedral–octahedral
planes, and in hedenbergite along the projection of the longer M2–O bonds. The orientation of the strain ellipsoid with temperature
in hedenbergite is close to that observed with pressure in pyroxenes. Along the jadeite–aegirine join instead the high-temperature
and high-pressure strain are differently oriented. 相似文献
10.
Alexej N. Platonov Klaus Langer Stanislav S. Matsyuk 《Physics and Chemistry of Minerals》2008,35(6):331-337
In the course of a thorough study of the influences of the second coordination sphere on the crystal field parameters of the
3d
N
-ions and the character of 3d
N
–O bonds in oxygen based minerals, 19 natural Cr3+-bearing (Mg,Ca)-garnets from upper mantle rocks were analysed and studied by electronic absorption spectroscopy, EAS. The
garnets had compositions with populations of the [8]
X-sites by 0.881 ± 0.053 (Ca + Mg) and changing Ca-fractions in the range 0.020 ≤ w
Ca[8] ≤ 0.745, while the [6]
Y-site fraction was constant with x
Cr3+
[6] = 0.335 ± 0.023. The garnets had colours from deeply violet-red for low Ca-contents (up to x
Ca = 0.28), grey with 0.28 ≤ x
Ca ≤ 0.4 and green with 0.4 ≤ x
Ca. The crystal field parameter of octahedral Cr3+ 10Dq decreases strongly on increasing Ca-fraction from 17,850 cm−1 at x
Ca[8] = 0.020 to 16,580 cm−1 at x
Ca[8] = 0.745. The data could be fit with two model which do statistically not differ: (1) two linear functions with a discontinuity
close to x
Ca[8] ≈ 0.3,
(2) one continuous second order function,
The behaviour of the crystal field parameter 10Dq and band widths on changing Ca-contents favour the first model, which is
interpreted tentatively by different influences of Ca in the structure above and below x
Ca[8] ≈ 0.3. The covalency of the Cr–O bond as reflected in the behaviour of the nephelauxetic ratio
decreases on increasing Ca-contents. 相似文献
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