PREDICTION OF LOCATION OF HIDDEN ORE DEPOSITS IN THE AGED ORE FIELDS:AN EXAMPLE FROM FENGHUANGSHAN ORE FIELD,TONGLING,CHINA

This paper discusses the strategy for successfully predicting the location of potential hidden ore bodies in aged ore field,and presents the result of location prediction of hidden ore bodies in Fenghuangshan ore field,Tongling.Innovative conceptual targeting procedures based on a genetic understanding of mineralization systems,carefully geological investigation and correct deduction,together with new geochemical and geophysical technology and integrating of comprehensive information are all very important for the successful prediction.In the aged Fenghuangshan ore field,through researching by application of the metallogenic theory of polygenetic compound ore deposits and triple-frequency induced polarization method and exploration tectono-geochemical method,we predicted location and quality of hidden ore bodies.According to the prediction,hidden high quality Cu-Au ore bodies of skarn type and porphyry type have been discovered.     

我国东部滨岸侵沉变异规律初探

滨岸地带自然环境多变,地质环境极为脆弱,但在社会经济发展中起着极为重要的作用。着重分析我国东部滨岸侵沉变异特征,研究滨岸侵沉变异地域分异规律与成因规律。     

Study of charge structure and radiation characteristic of intracloud discharge in thunderstorms of Qinghai-Tibet Plateau

The comprehensive observations on lightning discharges were conducted in Naqu area of Qinghai-Tibet Plateau in summer of 2002. The electric structures of thunderstorms and the characteristics of lightning discharges at initial stage were analyzed by using the observation data. The results show that most of intracloud (IC) lightning flashes were polarities inverted in thunderstorms with tripole electric charge structure and occurred between negative charge region located in the middle of the thunderstorm and positive charge region located at the bottom of the thunderstorm. The radiation characteristics of discharge processes in cloud with longer lasting time involved in Cloud-to-Ground (CG) lightning flashes were similar to that of IC discharges.A lot of radiation pulses were produced in these discharge processes. Because the IC discharges took place at the bottom of thundercloud and were near the ground, they may produce more serious damage to equipment on the ground therefore should not be neglected in lightning protection.     

Experimental research on reservoir sensitivity to stress and impacts on productivity in Kela 2 Gas Field

Kela 2 Gas Field, with high formation pressure (74.35MPa), high pressure coefficient (2.022) and difficulty of potential test and evaluation, is the largest integrated proved dry gas reservoir in China so far and the principal source for West-East Gas Development Project. In order to correctly evaluate the elastic-plastic deformation of rocks caused by the pressure decline during production, some researches, as the experiment on reservoir sensitivity to stress of gas filed with abnormal high pressure, are made. By testing the rock mechanic properties, porosities and permeabilities at different temperature and pressure of 342 core samples from 5 wells in this area, the variations of petro-physical properties at changing pressure are analyzed, and the applicable inspection relationship is concluded. The average productivity curve with the reservoir sensitivity to stress is plotted on the basis of the research, integrated with the field-wide productivity equation. The knowledge lays a foundation for the gas well productivity evaluation in the field and the gas field development plan, and provides effective techniques and measures for basic research on the development of similar gas fields.     

Legacies from three former manufactured-gas plants: impacts on groundwater quality

Groundwater contamination due to accidental releases of mono- and polycyclic aromatic compounds (MAHs and PAHs) from decommissioned manufactured-gas plants is an ongoing and litigious problem. The MAHs and PAHs are derived from coal tar, which was a by-product of the gas-manufacturing process. While originally designed to contain coal tar, the manufactured-gas plant structures that remain today have often degraded over time and are not completely leak-proof. Over a period of many years, subsurface water has seeped into and out of the structures, resulting in groundwater contamination. This was particularly true once the tops of the structures were removed. In this study, process-based simulations were conducted to estimate the groundwater-quality impacts of accidental releases of dissolved naphthalene (C₁₀H₈) from the sites of three former manufactured-gas plants. The results from one-dimensional, transient, unsaturated, near-surface fluid-flow and solute-transport simulations served as input to three-dimensional saturated subsurface fluid-flow and solute-transport simulations. The simulation results and sensitivity analysis reported here indicate that accidental releases of naphthalene had significant, negative impacts on groundwater quality at each of the three sites. Electronic Publication     

The Lanmuchang Tl deposit and its environmental geochemistry

Tl is a dispersed element and it seldom occurs in the form of independent minerals.The world annual production of Tl is about 13 ton, most of which is by-product separated from non-ferrous metal products. Lanmuchang is the only large-size independent Tl deposit in the world. Bio-enrichment and hydrothermal reworking are the two important metallogenic mechanisms of this Tl deposit. Samples of plant and animal organs and villagers’ urine as well as hair and nail (toenail) samples from the Tl mining district were analyzed. Analytical results showed that the contents of Tl, Hg and As are high, suggesting that the residents and villagers in the mining district have been affected by Tl-Hg pollution, and on the other hand, they can serve as the guidelines for ore prospecting. The contents of Tl, Hg, and As in human beings and other organic bodies depend largely on the background values of these metals in rock, ore, soil and water.     

Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance

Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite-andesines; and in high-A1 basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite-anorthites.∑REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondritenormalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area.     

The material conditions for research in France from 1600 to 1850: Physics,chemistry and astronomy

The income of the scientists in France during the 17th to the middle of the 19th century is reviewed and compared to the cost of their instruments. Only a small number of scientists received enough public money to be able to do full-time research; this number increased substantially after the Revolution. Most scientists had to have other sources of income, in particular to be able to purchase their instruments. Large research projects, generally decided and financed by the Academy of Sciences, took place during this period, requiring collaborative interdisciplinary efforts and a considerable logistics: they anticipate our present cooperative programs and giant research facilities.     

钢筋混凝土管桩反射波法的三维有限元分析

对桩-土系统用三维有限元模型和Wilson- 直接积分法计算钢筋混凝土管桩顶面的瞬态动力响应,并由此分析了管桩顶面不同测点的反射波信号特征及其与桩身缺陷的对应规律。计算结果表明：管桩顶部波传播的三维效应对桩身浅部局部缺陷深度的判断有较大的影响,所得结论对由反射波法检测管桩全截面断裂和局部缺陷以及传感器的合理布置有较大的指导作用。     

利用干涉图确定成像质量

从像质的概念出发,导出了像质评定的简单公式。在干涉图的每个选定点上测量条纹间的间隔和角度来计算几何光线的斜率误差,然后把这些角度误差画在一张图纸上用以表示几何点扩散函数的角度大小,可以方便而简洁地评定成像质量,避免了复杂的计算。