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101.
IntroductionTrial-and-error forward modeling of wide-angle seismic reflection/refraction traveltimes for 2-D velocity structure is extremely time-consuming, even for experienced data interpreters. For wide-angle seismic reflection/refraction experiments that consist of numerous shots along a single line, it is quite difficult through repeated trial-and-error forward modeling to construct a 2-D model that fits the data within acceptable limits (Cerveny, et al, 1977; ZHANG, et al, 200 . In ad… 相似文献
102.
Pierre Hudon In-Ho Jung Don R. Baker 《Physics of the Earth and Planetary Interiors》2002,130(3-4):159-174
Melting relations of β-quartz were experimentally determined at 1.0 GPa (1900±20 °C), 1.5 GPa (2033±20 °C), and 2.0 GPa (2145±20 °C) using a new high-pressure assembly in a piston–cylinder apparatus and substantial differences were found with data previously reported. The new melting data of β-quartz were combined and optimized with all available thermodynamic, volumetric, and phase equilibria data for β-cristobalite, β-quartz and coesite to produce a P–T liquidus diagram for silica valid up to 6.0 GPa. Using the new optimized thermodynamic parameters, the invariant point β-cristobalite+β-quartz+liquid and β-quartz+coesite+liquid were determined to lie at 1687±17 °C and 0.457 GPa, and 2425±25 °C and 5.00 GPa, respectively. 相似文献
103.
104.
Fe‐rich metapelitic granulites of the Musgrave Block, central Australia, contain several symplectic and coronal reaction textures that post‐date a peak S2 metamorphic assemblage involving garnet, sillimanite, spinel, ilmenite, K‐feldspar and quartz. The earliest reaction textures involve spinel‐ and quartz‐bearing symplectites that enclose garnet and to a lesser extent sillimanite. The symplectic spinel and quartz are in places separated by later garnet and/or sillimanite coronas. The metamorphic effects of a later, D3, event are restricted to zones of moderate to high strain where a metamorphic assemblage of garnet, sillimanite, K‐feldspar, magnetite, ilmenite, quartz and biotite is preserved. Quantitative mineral equilibria calculations in the system K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3 (KFMASHTO) using Thermocalc 3.0 and the accompanying internally consistent dataset provide important constraints on the influence of TiO2 and Fe2O3 on biotite‐bearing and spinel‐bearing equilibria, respectively. Biotite‐bearing equilibria are shifted to higher temperatures and spinel‐bearing equilibria to higher pressures and lower temperatures in comparison to the equivalent equilibria in K2O–FeO–MgO–Al2O3–SiO2–H2O (KFMASH). The sequence of reaction textures involving spinel is consistent with a D2 P–T path that involved a small amount of decompression followed predominantly by cooling within a single mineral assemblage stability field. Thus, the reaction textures reflect changes in modal proportions within an equilibrium assemblage rather than the crossing of a univariant reaction. The D3 metamorphic assemblage is consistent with lower temperatures than those inferred for D2. 相似文献
105.
Lunan stone forest is a kind of typical karst in China, which is mainly developed under red soil. In the winter of 1999, three study sites were chosen in stone forest national park according to vegetation cover, geomorphologic location and soil types. CO2 concentration was measured with Gastec pump at different depths of soil (20, 40, 60 cm) and at the same time soil samples were gathered and soil properties such as soil moisture, pH, soil organic content were analyzed and the total number of viable microbes were counted in laboratory. In the study, dependent variable was chosen as the mean soil log (PCO2), and soil properties were chosen as the independent variables. Multiple stepwise regression analysis showed that the total amount of microbes and soil moisture are the best indicators of the CO2 production, with the equation LOG(PCO2) = - 0.039(TNM) - 0.056(Mo) + 1.215 accounting for 86% of the variation of the soil CO2 concentration, where TNM is the total number of microbes in the soil and Mo is the moisture of soil sample. 相似文献
106.
107.
光催化氧化法处理难降解废水的研究进展 总被引:8,自引:3,他引:8
综述了光催化氧化处理难降解废水的研究现状及发展趋势。介绍了影响光催化氧化反应速率的因素及光催化氧化法在处理难降解废水中的应用。 相似文献
108.
109.
Hans-Joachim Massonne 《Earth and Planetary Science Letters》2003,216(3):347-364
The petrography and chemical composition of minerals of quartz-rich diamondiferous rocks from the Kokchetav Massif, especially the zonation of garnet, were studied and compared with diamondiferous quartzofeldspathic rocks from the Saxonian Erzgebirge. Many compositional and textural features were found to be similar. For instance, microdiamonds are enclosed systematically in a specific intermediate growth zone of garnet in these rocks. On the basis of experimental data, a magmatic scenario was constructed to check if the quartz-rich diamondiferous rocks are of magmatic origin. By this, the P-T paths, derived here for the Kokchetav rocks, and the textural observations it is concluded that the minerals of the diamondiferous rocks have crystallized from silicate melts. These melts originated by anatexis of deeply submerged metasediments (Erzgebirge: at T as high as 1200°C, Kokchetav Massif: at 50-100°C lower T) and ascended from at least 200 km depth. Relics of the pre-anatectic evolution are still present, for instance, as garnet cores. After ascent and emplacement of the magma in deep portions of thickened continental crust (Kokchetav Massif: 45-50 km close to 800°C, Erzgebirge: 55-60 km at 30-50°C lower T) considerable quantities of (white and/or dark) micas formed by peritectic reactions from melt. For instance, garnets could be resorbed at this stage and biotite grew instead. After the magmatic stage, retrogression took place much stronger in the Kokchetav Massif. This was accompanied by deformation transforming broadly the magmatic texture of quartz-rich diamondiferous rocks from the Kokchetav Massif to a gneissic texture. 相似文献
110.
深圳市东湖矿泉水形成机理探讨 总被引:5,自引:0,他引:5
深圳市东湖矿泉水是自然界十分稀少的锶—锌—偏硅酸碳酸复合型矿泉水,通过对矿泉水赋存地的地质与水文地质条件的分析,并结合其水文地球化学特征,认为东湖矿泉水形成的主要控制性因素是构造作用和变质作用;在特定的水文地质条件下,深部碳酸盐类岩石受热硅化变质而产生大量CO2气体,使得各种化学元素在含有大量CO2的地下水的溶滤作用下不断迁移和富集而形成该区地下水中良好的元素组合。在其特征成分中,偏硅酸来自裂隙渗透水的溶滤和岩浆期后热液水的作用,微量元素锶主要来源于钾长石、钙长石,锌则主要来自岩浆活动以及岩脉中的黑云母、角闪石、辉石等铁镁硅酸盐矿物;并认为目前矿泉水含水层仍处于良好的地质环境保护下。 相似文献