Influence of Arctic Oscillation on winter climate over China

In this study the relationship between the Arctic Oscillation (AO) and climate in China in boreal winter are investigated. Correlation analysis for the last 41 years shows that the winter temperature and precipitation in China change in phase with AO. High positive correlation (>0.4) between temperature and AO appears in the northern China. High correlation coefficients between precipitation and AO cover the southern China (close to the South China Sea) and the central China (between 30o-40oN and east of ~100oE), with the values varying between +0.3 and +0.4. It is found that during the past several decades the precipitation was strongly affected by AO, but for the temperature the Siberian High plays a more important role. At the interdecadal time scale the AO has significant influence on both temperature and precipitation. Multivariate regression analysis demonstrates that AO and the Siberian High related variance in temperature and precipitation is 35% and 11% respectively. For precipitation, however the portion is rather low, implying that some other factors may be responsible for the changes in precipitation, in addition to AO and the Siberian High.     

Water discharge changes of the Changjiang River downstream Datong during dry season

Based on hydrometric data and extensive investigations on water-extracting projects, this paper presents a preliminary study on water discharge changes between Datong and Xuliujing during dry season. The natural hydrological processes and human factors that influence the water discharge are analyzed with the help of GIS method. The investigations indicate that the water-extracting projects downstream from Datong to Xuliujing had amounted to 64 in number by the end of 2000, with a water-extracting capacity up to 4,626 m3/s averaged in a tidal cycle. The water extraction from the Changjiang River has become the most important factor influencing the water discharge downstream Datong during dry season. The potential magnitude in water discharge changes are estimated based on historical records of water extraction and a water balance model. The computational results were calibrated with the actual data. The future trend in changes of water discharge into the sea during dry season was discussed by taking into consideration of newly built hydro-engineering projects. The water extraction downstream Datong in dry season before 2000 had a great influence on discharges into the sea in the extremely dry year like 1978-1979. It produced a net decrease of more than 490 m3/s in monthly mean discharges from the Changjiang into the sea. It is expected that the water extraction will continually increase in the coming decades, especially in dry years, when the net decrease in monthly mean water discharge will increase to more than 1000 m3/s and will give a far-reaching effect on the changes of water discharge from the Changjiang into the sea.     

Seasonal variation of the soil seed bank of grasses in central Argentina as related to grazing and shrub cover

The objectives of this research were to (a) study seasonal variation of the seed bank of grasses in two areas with different grazing history, (b) analyse the effect of the presence of shrubs on the seed bank and (c) study seed viability and dormancy in buried seeds of Piptochaetium napostaense and Stipa tenuis. The seed density of grasses was in general low and showed seasonal variation. Most of the grasses showed maximum seed density in December when seed dispersal occurs. Shrub cover did not show a marked influence in seed accumulation. The relatively high number of damaged seeds suggests that predation may be an important factor in seed bank dynamics in the Caldenal. Seeds of dominant perennial forage grasses showed dormancy that could explain, at least in part, persistence of these species in spite of periodical disturbance.     

南天山西段古生代火山岩Ar-Ar年龄新资料

根据新近采自中国南天山西段志留-泥盆系乌帕塔尔坎群中的安山岩样品和石炭-二叠纪康克林组上部英安岩角砾样品的全岩Ar-Ar定年测试,乌帕塔尔坎群安山岩的坪年龄为427.70±0.60 Ma,等时年龄为426.96±4.57 Ma; 康克林组上部的英安岩角砾的坪年龄为288.16±0.40 Ma,等时年龄为289.18±2.02 Ma.测试结果为研究中国南天山(西段)古生代造山带的构造体系提供了新的依据.     

从江县翁浪金矿床容矿岩石与围岩蚀变及其找矿标志

文章简单介绍了构造蚀变岩型金矿翁浪金矿床的容矿岩石和围岩蚀变特征，指出该类矿床的找矿标志，对进一步寻找此类矿床有一定的意义。     

加强资金管理促进地勘经济发展

资金结构的不合理使一些地勘单位的发展步履维艰。增加财务杠杆利益,优化资本结构,保持良好的财务状况,发挥资金的有效利用率,才能实现资金的最大利润率,使地勘单位适应市场经济环境,提高其经济实力。     

细菌浸铜技术在紫金山铜矿的应用

介绍了生物浸矿技术在紫金山铜矿的应用及在这一过程中发现的一些问题，并提出了有待进一步解决的一些问题。     

从流体包裹体研究探讨金属矿床成矿条件

根据作者多年来对流体包裹体的研究成果，参考了国内外的研究结论，提出了一个新的成矿流体分类方案，并评述了我国若干典型金属矿床的研究状况，由此探讨了金属矿床的形成机制。     

锡铁山铅锌矿地质特征、矿床成因及找矿标志

通过找矿工作的实践，认为锡铁山铅锌矿床是由火山喷流沉积—后期热液叠加改造富集的块状硫化物多金属矿床。区域上NW—SE向早古生代形成的裂谷带，三级盆地内沉积的晚奥陶世滩间山群的大理岩与绿片岩系是表区找矿的最佳区段。而绢云绿泥斜长片岩、含碳质绢云绿泥片岩、白色大理岩、条带状大理岩是铅锌矿的最重要的找矿标志。     

黄铁矿中富铜闪锌矿的斑点状结构

内蒙古大井矿床中产出一种奇特的闪锌矿斑点结构，闪锌矿斑点包裹于黄铁矿中，通过显微镜研究和电子探针分析，认为该闪锌矿斑点属罕见的富铜闪锌矿，ω(Cu)为3．87％—6．99％，平均5．37％，其成因与在黄铜矿中的闪锌矿斑点一样，是高温下出溶作用的产物。