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771.
本文介绍了砂土本构模型研究的历史及现状,特别是对国内较少涉及的动弹塑性本构模型研究情况作了详细的介绍,并就作者的理解体会作了一些评价。 相似文献
772.
The C and H isotopic compositions of the methane in more than 160 gas samples from 10 basins in China are presented in this paper.The natural gases are classified as four types: biogenic gas ,bio-thermocatalytic transitional gas, gas associated with condensate oil ,and coal-type gas. The isotopic compositions of these gases closely related to the depositional basins, the types of organic matter,the stages of thermal evolution and the genetic characteristics of different gas reservoirs.Studies of the C and H isotopic compositions of terrigenous natural gases will provide valua-ble information on the prospecting and development of natural gases of different genetic types. 相似文献
773.
An experimental study has been carried out to determine the partition coefficients of tungsten between aqueous fluids and
granitic melts at 800 °C and 1.5 kb with natural granite as the starting material. The effects of the solutions on the partition
coefficients of tungsten show a sequence of P > CO
3
2−
> B > H2O. The effects are limited (generallyK
D
< 0.3) and the tungsten shows a preferential trend toward the melt over the aqueous fluid. The value ofK
D
increases with increasing concentration of phosphorus; theK
D
increases first and then reduces with the concentration of CO
3
2−
when temperature decreases, theK
D
between the solution of CO
3
2−
and the silicate melt increases, and that between the solution of B4O
7
2−
and the silicate melt decreases. The partition coefficients of phosphorus and sodium between fluids and silicate melts have
been calculated from the concentrations of the elements in the melts. TheK
D
value for phosphorus is 0.38 and that for sodium is 0.56. Evidence shows that the elements tend to become richer and richer
in the melts. 相似文献
774.
Types and distribution of silver ore deposits in China 总被引:2,自引:0,他引:2
Silver is generally recovered as a by- and co-product along with Au, Pb, Zn, Cu, Sb, Bi, Hg, Sn and W from polymetallic and
gold mines in China. Chinese silver deposits can be classified into five principal types according to host rocks. These types
and their host rocks are: (1) marine volcanic-sedimentary rocks hosting (la) massive sulfide Pb-Zn-(Cu)-Ag ores and (1b) stratiform
Ag-(Au) ores; (2) continental volcanic-sedimentary rocks containing (2a) various polymetallic-silver veins and/or stockworks,
and (2b) Ag-(Au) veins in pyroclastic rocks; (3) rocks affected by metasomatic processes including (3a) complex Sn-polymetallic-Ag
ores, (3b) Pb-Zn-(Cu)-Ag skarns, (3c) associated W-Ag quartz veins and/or skarns, and (3d) Ag-(Au) zones and veins in altered
carbonate rocks; (4) metamorphic-intrusive rocks, principally Ag-(Au) veins in sheared and brecciated metamorphic rocks; and
(5) sedimentary rocks including (5a) stratiform Pb-Zn-Ag ores in carbonate rocks, (5b) Ag-V mantos in black shales, and (5c)
Cu-(Ag) layers in red sandstones. A sixth grouping includes gossans. The tectonic settings, geological features, and temporal
and spatial distribution of these different types of silver occurrences indicate that silver mineralization reflects to a
great extent the evolution of tectonic environments in China throughout geological time. Type 1 is generally developed in
association with several fold belts from the Caledonian to Yanshanian orogens, while types 2, 3 and 4 correlate with rejuvenation
of the eastern China continent during the Mesozoic period. The three subgroups of type 5 are recognized in different stages
and various sedimentry and diagenetic environments during the development of paraplatforms and fold belts. Type 6 results
from recent weathering of existing sulfide ores or protores.
Editorial handling: DR 相似文献
775.
为了解奂徐集复杂断块地区含油范围预测问题,使用了地震多参数分
析法。多参数分析法是充分利用各种地球物理参数(振幅、频率、相位及
速度等),并将各参数测定结果与地质因素相结合,引用判别函数以判定
其含油性,进而预测早期油水边界。利用地震多参数分析法,在徐集地区
预测早期油水边界已取得了较好的效果。 相似文献
777.
778.
779.
内蒙古中部二叠纪碱性花岗岩及其地球动力学意义 总被引:95,自引:0,他引:95
西伯利亚板块南缘白音乌拉-东乌珠穆沁旗带的碱性花岗岩(Rb-Sr年龄276-286Ma)生成于张性的构造环境,较西伯亚板块同中朝板块之间晚泥盆世-早石炭世的碰撞事件晚约60Ma,属于造山后的A型花岗岩,可作为造山作用结束的标志。但在中朝板块北缘晚石炭世-二叠纪只发育钙碱性的晚造山花岗岩,直到三叠纪才出现碱性正长岩。相邻两大板块边缘之间岩浆活动的非对称性可能是受板块间面积和质量差别的制约。 相似文献
780.
The Zoulang Nanshan Caledonian Subduct ion Complex in the Northern Qilian Mountains and Its Dynamics 总被引:1,自引:0,他引:1
Xu Zhiqin Xu Huifen Zhang Jianxin Li Haibing Zhu Zhizhi Qu Jingchuan Institute of Geology Chinese Academy of Geological Sciences BeijingChen Daizhang Chen Jinlu China University of Geosciences Beijingand Yang KaichunNo. Q ilian Geological Party Bureau of Geology Mineral Resources of Q inghai Province Q ilian County Q inghai 《《地质学报》英文版》1994,68(3)
The front of the Zoulang Nanshan Caledonian volcanic island arc zone in the northern Qilian Mountains is a forearc accretionary terrane, composed of multiple accretionary volcanic island arcs, flysch accretionary wedges,high-pressure metamorphosed detachment zones and remnants of ophiolites. It resulted from the northeastward subduction of the Early Palaeozoic Qilan oceanic crust beneath the Alxa block. High-pressure metamorphism, which occurred during the subduction, progressed through three stages: the initial stage of medium T-high P,the main stage of temperature decrease and pressure increase, and the lag stage of pressure decrease and temperature increase. Finally the paper presents a retrotrench subduction dynamic model indicative of northward subduction of the central Qilian block and southward accretion of the Alxa block during the period of 450-500 Ma. 相似文献