共查询到20条相似文献，搜索用时 31 毫秒
1.
《《地质学报》英文版》1988,62(3)
Analysis of the variations in the three-dimensional structural forms of the tungsten veins in the Xihuashantungsten district has proved that echelon structures of the veins were formed by the changes in stress directionthat caused the breakdown of the individual single veins. and are different from the echelon faults formed inshear zones. Echelon structures of the veins were produced near the lithologic boundary as a result of the rota-tion of stress direction in their neighbourhood and their control of vein distribution. The change in the echelonpattern caused by the varlation in the attitude of lithologic boundary surface in the district is an interestingstructural phenomenon, The echelon structures also reflect the variation characteristics of adjacent veins in theprocess of their propagation. 相似文献
2.
This paper is dedicated to numerical simulations of spiral–vortical structures in rotating gaseous disks using a simple model based on two-dimensional, non-stationary, barotropic Euler equations with a body force. The results suggest the possibility of a purely hydrodynamical basis for the formation and evolution of such structures. New, axially symmetric, stationary solutions of these equations are derived that modify known approximate solutions. These solutions with added small perturbations are used as initial data in the non-stationary problem, whose solution demonstrates the formation of density arms with bifurcation. The associated redistribution of angular momentum is analyzed. The correctness of laboratory experiments using shallow water to describe the formation of large-scale vortical structures in thin gaseous disks is confirmed. The computations are based on a special quasi-gas-dynamical regularization of the Euler equations in polar coordinates. 相似文献
3.
The dissipative structure is an ordered structure.When a ssyterm is far from reaching equilibrium in the condition of non-equilibrium and exchanges some energy and material with the surroundings,this structure will be formed and preserved.Starting with the analysis of practical data,we attempt to use this theory to discuss the tectono-geochemical problems of some rock and ore-forming systems in faults.1.Ordered structure:Under the geological condition,due to the opening of a system in which energy and material are involved in geochemical action,the entropy tends to reduce gradually and substances evolve from non-ordered to ordered in structure.In the processes of formation of rocks and ores in faults,various layer-bands will be formed in rocks.2.Functional action:The physico-chemical activities which include pressure-creeping and thermal-diffusion as well as liquid diffusion have been shown.3.Fluctuating cycle:In the process of metamorphism,various changes in pressure,temperature and liquid are of fluctuation and periodicity.These may play an important role in the formation of rocks and minerals and the occurrence of ordered structures in fault zones.A few examples of mineral deposits in the middle and lower Yangtze River Valley are presented here,and the dissipative activities of rock-forming minerals and mineral-forming elements have been preliminarily established. 相似文献
4.
Yuan Xuecheng 《《地质学报》英文版》1989,63(3):211-225
Through recent study, the author considers that the north-south-trending Kangding-Honghe tectonic belt is not a marginal uplift zone of the Yangtze Platform but a Tethyan-type collisional tectonic belt of which the crust-upper mantle can be structurally divided into three layers. The upper layer is the brittle upper crust, dominated by overthrusting and imbrication; the middle layer is the plastic lower crust and part of the upper mantle, represented by compression and shortening; and the lower layer is the upper mantle, probably belonging to the Yangtze Platform in light of the thickness of the lithosphere. 相似文献
5.
The Stress–Strain State of Recent Structures in the Northeastern Sector of the Russian Arctic Region
Doklady Earth Sciences - Complex research to determine the stress–strain state of the Earth’s crust and the types of seismotectonic destruction for the northeastern sector of the... 相似文献
6.
Lin Chuanyi 《中国地球化学学报》1990,9(2):132-136
Electronic structures of square planar coordinated transition metal ions in BaCuSi4O10 and CaCrSi4O10 are investigated using the ligand-field theory (LFT), angular overlap model (AOM) and iterative extended Hückel molecular
orbital theory (IET). The electronic energy levels of the natural mineral dioptase are also investigated, in which the Cu2+ ions occupy the sites of pseudo D4h symmetry. Both LFT and AOM predict that the crystal-field levels of transition metal ions in these compounds follow such
an order that E (2B1g <E(2B2g <E(2A1g )<E(2Eg ), and the frequencies of the crystal-field transitions obtained from point charge calculations are in good agreement with
those observed. However, the energy-level order cannot be determined unambiguously from the IET calculation because it depends
on the values of parameters chosen for the calculation. 相似文献
7.
《International Geology Review》2012,54(8):736-753
Subtidal, intertidal, and supratidal carbonate facies are recognized in the Upper Jurassic (Kimmeridgian)-Upper Cretaceous (Cenomanian) peritidal carbonates of the Fele area (Western Taurides, Turkey). Vertical stacking patterns of these facies are of a cyclical character; shallowing upward is the trend of the cyclicity in these carbonate facies. In-situ karstic breccias, collapse breccias, caliche (laminar calcrete), “Microcodium” accretion, and root casts are structures commonly indicative of third-order sequence boundaries. However, mud cracks, solution pores or vugs, sheet cracks, loferites, and birds-eye structures are commonly delineated by parasequence boundaries. In-situ or collapse breccias can be genetically derived from sheet cracks, mud cracks, solution pores or vugs, and birds-eye structures with increasing exposure time. The use of such sedimentary structures in the recognition of sequence boundaries is highly practical in the ancient carbonate platforms of the world, inasmuch as the sequence boundaries, as demonstrated in this study, correlate with the eustatic sea level curves. 相似文献
8.
LU Anhuai HUANG Shanshan LIU Rui ZHAO Dongjun QIN Shan 《《地质学报》英文版》2006,80(2):161-169
The micro-channels usually refers to structural channels of minerals with aperture in the range of 0.3 nm to 2.0 nm. Such microchannels include, Mn-O octahedron channel filled by K in cryptomelane, and channel constructed by Si-O and AI-O tetragonal molecular sieve filled by Na and Ca in zeolite, and effectively have the function of molecular sieve. Here we point out that ultramicrochannels of natural minerals have apertures below 0.3 nm with the features of ionic sieves. The ultra-microchannels of mineral feldspar, accounting for half mass of the Earth＇s crust, have been largely ignored because the aperture is too small. In this work, we present that feldspar displays a certain degree of ion exchange and owns a feature of channel structure under both high and low temperatures. At high temperature, Na^＋ can enter the channels of feldspars. The content of Na2O in feldspar increases up to 15.9%. At middle temperature, Pb^2＋ can also enter the channels of feldspar as the result of ion exchange, leading thus to the formation of Pb-feldspar. At room temperature, about 97.94% Cd^2＋ can be removed and Cd-feldspar can be obtained. These phenomena indicate typical effects of ultra-microchannels of feldspar, which may be suggested as a potential for the treatment of heavy metal pollution and nuclear waste. The ultra-microchannels of natural minerals have played special role in migration and exchange of geomaterials. The molecular sieves of microchannels of a few natural minerals have the property of purifying molecular gas pollution. And the ionic sieves of ultramicrochannels of most natural minerals can purify ionic water contaminates. 相似文献
9.
Field investigation and laboratory work reveal that inhomogeneity of the deformation of the Xiannüshan fault is mainly characterized by lateral zonation, longitudinal segmentation and downward stratification. Based on these results, a 3-D deformational structure model of the fault was established and its geometrical and kinematic characteristics in two main deformational stages i.e. the main Yanshanian and Himalayan were discussed. The directions of principal and the differential stresses in these two stages were determined by using conjugate joints, striations of fault planes and microstructures of the fault zone. The direction of (1 is N-S in direction with differential stresses of 150(250 MPa in the Yanshanian, and N70E with a differential stress ranging from 80-120 MPa in the Himalayan. 相似文献
10.
WU Shuren 《《地质学报》英文版》1999,73(2):163-172
Field investigation and laboratory work reveal that inhomogeneity of the deformation of the Xiannüshan fault is mainly characterized by lateral zonation, longitudinal segmentation and downward stratification. Based on these results, a 3-D deformational structure model of the fault was established and its geometrical and kinematic characteristics in two main deformational stages i.e. the main Yanshanian and Himalayan were discussed. The directions of principal and the differential stresses in these two stages were determined by using conjugate joints, striations of fault planes and microstructures of the fault zone. The direction of (1 is N-S in direction with differential stresses of 150(250 MPa in the Yanshanian, and N70E with a differential stress ranging from 80-120 MPa in the Himalayan. 相似文献
11.
ZHANG Jinjiang ZHAO Lan LIU Shuwen 《《地质学报》英文版》2006,80(6):864-874
The Longquanguan shear zone is an important structural belt in the North China Craton, separating the underlying Fuping complex from the overlying Wutai complex. This shear zone has experienced three episodes of deformation： the first and main episode is a ductile top-to-ESE shear along the gently northwest-west dipping foliations, while the other two episodes are later collapse sliding. Prolonged granites parallel to the shear foliations make one of the main compositions of the Longquanguan shear zone. These granites experienced deformation to form mylonitic rocks when they emplaced during the first episode of deformation. Structural characters of the granites and their contacts to the country rocks indicate that these granites possibly resulted from in-situ partial remelting by shearing, i.e., they are syn-deformational granites. Monazites in these mylonitic granites are magmatic minerals and their crystallization ages may represent ages of the magmatic events, and also the ages for the main deformation of the Longquanguan shear zone. Monazite electronic microprobe dating were carried on two samples of granite, which gives multiple peak ages, among which 1,846 Ma and 1,877 Ma are the main peak ages for the two samples. These ages represent the main deformation of the Longquanguan shear zone, which is consistent with the main regional geological event at about 1,850 Ma caused by the collision between the Eastern and Western Blocks in North China. The good match between the monazite ages and the corresponding regional tectono-thermal events shows the feasibility and reliability of monazite electronic microprobe dating. 相似文献
12.
A Calculation Model for Corrosion Cracking in RC Structures 总被引：5，自引：0，他引：5
A novel calculation model is proposed aiming at the problem of concrete cover cracking induced by reinforcement corrosion. In this article, the relationship between the corrosion depth of the bar and the thickness of the rust layer is established. By deducing the radial displacement expression of concrete, the formula for corrosion depth and corrosion pressure before cracking is proposed. The crack depth of cover in accordance with the maximum corrosion pressure is deduced; furthermore, the corrosion depth and corrosion pressure at the cracking time are obtained. Finally, the theoretical model is validated by several experiments, and the calculated values agree well with the experiment results. 相似文献
13.
Jiang Yicheng Tang Jiaxiang School of Civil Engineering Huazhong University of Science Technology Wuhan 《中国地质大学学报(英文版)》2001,12(1)
INTRODUCTIONConcept of base isolation has attracted considerable attention in recent years (Sun et al., 1994). The basic isolationsystem consists of an array of bearings between the base of thebuilding and its foundation. It shifts the fundamental frequencyof the structure away from the energetic region of the earthquake spectrum and limits the earthquake energy transmitted tothe superstructure (Tang and Liu, 1993 ). Base isolation isused widely to protect structures from the destructive… 相似文献
14.
Yang Jun* Li Li Fan Aiwu School of Civil Engineering Mechanics Huazhong University of Science Technology Wuhan China 《中国地质大学学报(英文版)》2005,16(4):349-353
Theapplicationofreinforcedconcrete(RC)shear wallbuildingsisquitecommoninseismicare as.Shearwalls,withlargerigidityandhigh strength,aretheprimarymembersforresistinghori zontalloadsinbuildingstructures.Butunderthe forceofasevereearthquake,shearwallsareprone… 相似文献
15.
Please refer to the attachment(s) for more details. 相似文献
16.
Luchitskaya M. V. Sokolov S. D. Verzhbitsky V. E. Vatrushkina E. V. Ganelin A. V. Golionko B. G. 《Doklady Earth Sciences》2019,484(1):48-52
Doklady Earth Sciences - New U–Pb SIMS zircon datings from granitoid plutons and dikes of Western Chukotka, together with data obtained earlier, confirm that postcollisional granitoid... 相似文献
17.
Geotectonics - Analysis of the identification of hydrocarbon generation foci (hydrocarbon kitchens) by state-of-the-art methods has been carried out. Radial–concentric structures in the... 相似文献
18.
19.
Gold enrichment mechanism of ore-forming fluid is the essence of gold metallization.This paper summarizes the distinguishing symbols of mantle fluid and effect of crust-mantle structure on fluid movement. Fluid moving processes include osmosis, surge, gas-liquid alterna-tion and mutation of fluid speed. During fluid movement, gold will be enriched gradually. Final-ly, a layered circulatory system is illustrated in this paper. 相似文献
20.
Coupling Effects on Gold Mineralization of Deep and Shallow Structures in the Northwestern Jiaodong Peninsula, Eastern China 总被引：19，自引：0，他引：19
YANG Liqiang DENG Jun WANG Qingfei ZHOU Yinghua 《《地质学报》英文版》2006,80(3):400-411
For understanding the possible deep-seated processes and geodynamic constrains on gold mineralization, comprehensive physicochemical and geochemical studies of gold mineralization have been undertaken within the paleo-lithosphere framework during the metailogenic epoch from the northwestern part of the Jiaodong Peninsula in this paper. A general image of the paleo-crust has been remained although it has been superimposed and reformed by post-metailogenic tectonic movements. The gold ore deposits occur usually in local uplifts and gradient belts featuring a turn from steep to gentle in granite-metamorphic contact zones, relative uplifts of gradient zones of the Curier isothermal interfaces, depressions of the Moho discontinuity and areas where depth contours are cut by isotherms perpendicularly. Gold mineralization and lithogenesis are characterized by high temperature, low pressure and high strength of thermal flux. The depth of mineralization ranges from 0.8 to 4.5 km. The depth of the top interface of the granitic complex in the metallogenic epoch is about 3 km. There is a low-velocity layer （LVL） at the bottom of the upper crust with a depth close to 19.5 km, which may be a detachment belt in the crust. The appearance of the LVL indicates the existence of paleo-hyperthermal fluid or relics of molten magma chambers, which reflects partial melting within the crust during the diagenetic and metallogenic epochs and the superposition effects of strike-slip shearing of the Taulu fault zone. The subsidence of the Moho is probably attributed to the coupling process of the NW-SE continental collision between North China and the Yangtze Block and the strike-slip movement of the Tanlu fault accompanied with underplating of mantle magma in the northwestern part of the Jiaodong Peninsula. The underplating of mantle magma may result in partial melting and make granite magma transfer upwards. This is favorable for the migration of metallogenic materials from deep to shallow to be enriched to form deposits. Coupling interactions between the strike-slip of the Taulu fault, the underplating of mantle magma, partial melting within the crust, and hyperthermal fluid, etc. may be the important factors controlling the gold mineralization and spatial structures in the metailogenic system. 相似文献