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361.
362.
甘肃桦树沟(铁)铜矿床的成因机制 总被引:4,自引:0,他引:4
矿床地质地球化学特征研究结果表明,随着古陆边缘弧-槽-盆体系的发生与发展,元古代基底火山(沉积)岩系经深循环水(海水)-热系统的作用,成矿物质被浸出和搬运,并经海底喷溢作用沉淀于海盆洼地中形成桦树沟矿床含铜建造,后期变质作用使成矿物质活化、转移和富集。桦树沟矿床为喷气(流)沉积-变质改造型(铁)铜矿床。 相似文献
363.
若尔盖高原及其周围山地的冻土和环境 总被引:8,自引:4,他引:8
若尔盖高原内部年平均气温0.6~3.3℃,气温年较差19.1~21.2℃,已不具备多年冻土形成和保存的气候条件。据1992年7月间试坑和钻孔测温,在1.0~2.2m深处地温为5~8.4℃,浅层地下水温6.0~7.8℃,由此判断不存在多年冻土,季节冻结深度为1.0~2.0m。据冻土现象和试坑资料判断,周围山地海拔4150~4200m以上发育山地岛状多年冻土。区内沼泽演化表明,部分沼泽已疏干或向疏干趋势发展,草场退化和草原沙化已成为本区生态环境的重要问题,并已影响畜牧业发展 相似文献
364.
利用光粘弹性实验方法模拟了地下工程中圆截面巷道围岩及冻结壁的蠕变过程,给出了巷道围岩和冻结壁的应力分布规律及随时间的变化规律,为地下工程的设计及预报提供了一种有效的实验手段。 相似文献
365.
In this paper,the Gutenberg-Richter model is used to generate seismic events.The events that satisfy the random distribution are also generated.With those events,the natural probability distribution of Load and Unload Response Ratio(LURR),which measures quantitatively the degree of instability of a nonlinear system,is discussed.The study is based on stress energy release,which is chosen as the response of nonlinear system F3.The comparative results from the observation catalogue and generating data are also studied.It is revealed that the natural probability of LURR is mostly stable when the sample number is sufficient.The lower the natural probability of LURR,the more the precursory is information it may contain.The influence of Y3 resulting from the sample number and the magnitude range of events is also discussed. 相似文献
366.
Taking the active fault network as the structural frame, the Chinese mainland and its periphery can be regarded as a system of "fault movement and seismogeny." By using the self-coupling method, preliminary study shows that the seismogenic system is a time-ordered dissipation system. The time order in the state far from equilibrium is established and maintained through mass and energy exchanges between the system and the surroundings. The evolution of the seismogenic system follows some properties of unbalanced phase change, namely, critical retard, bifurcation, entropy reduction, etc. 相似文献
367.
Chemical composition of upper crust in eastern China 总被引:4,自引:0,他引:4
In an area of 3.3×106 km2 within eastern China, 28 253 rock samples were collected systematically and combined into 2718 composite samples which were
analyzed by 15 reliable methods using national preliminary certified reference materials (CRMs) for data quality monitoring.
The average chemical compositions of the exposed crust, the sedimentary cover and the exposed basement as well as the upper
crust for 76 chemical elements in eastern China are given.
A key basic geology projcct supported by Ministry of Geology and Mineral Resources of China. 相似文献
368.
The hydrocarbon generation mechanism and the three-stage type model of hydrocarbon generation for carbonate source rocks 总被引:1,自引:0,他引:1
The diagenetic mechanism and process of carbonate rocks, which is different to that of clastic rocks, decides the existence
of different existing state organic matters in carbonate rocks. This has been verified by both the microscopic observation
of organic petrology and the analysis of organic geochemistry of many samples. Based on the hydrous pyrolysis simulation experiment
of the low-mature carbonate rocks, the contrasting study on the yield and their geochemistry characteristics of different
existing state soluble organic matters of a series of various maturity samples shows that the different existing state organic
matters make different contributions to hydrocarbon generation during every evolution state. So that, the hydrocarbon generation
process of carbonate rocks can be summarized as the following three stages: the first is the direct degradation of biogenic
bitumen macromolecules during the immature stage, the second is the thermal degradation of a large amount of kerogen at the
mature stage, the last stage is the expulsion or release of inclusion organic matter owing to the increased thermal expansion
pressure during the high evolution stage.
Part of achievements of the Eighth Five-Year National Science-Technology Key-Task Project “85-102-02-07”. 相似文献
369.
The Zoige Basin is located in the eastern margin of the Qinghai-Xizang Plateau, in which two cores, RH and RM, have been drilled,
with the depths of 120 m and 310 m respectively. The former with the bottom age of 826 kaB. P. has been divided into 21 stages
according to the multi-proxy analysis, which could be basically compared with the oxygen isotope record of deep-sea core.
The palaeoclimatic and palaeoenvironmental process of the Zoigê Basin over the past 900 kaB. P. is reconstructed, and the
comparison of core RH with the Luochuan Loess record is made. 相似文献
370.
Crustal structure of Dabieshan orogenic belt 总被引:2,自引:0,他引:2
Chunyong Wang Xiankang Zhang Buyun Chen Xuebo Chen Songyan Song Jinhan Zheng Hongxiang Hu Hai Lou 《中国科学D辑(英文版)》1997,40(5):456-462
The crustal structures ofP velocity and density on the deep seismic sounding profile across the Ilabieshan orogenic belt are presented. There is a 5-km-thick
crustal “root” between the Yuexi and Xiaotian where the elevation is highest on the profile. An apparent Moho offset of 4.
5 km beneath the Xiaotian-Mozitan fault marks the paleo-suture of the Triassic collision. A high-velocity anomaly zone at
the depth below 3 km beneath the ultra-high pressure (UHP) zone may be correlated to the higher content of UHP metamorphic
rocks.
Project supported by the National Natural Science Foundation of China and the Joint Earthquake Science Foundation. 相似文献