Chemical forms of heavy metal contaminants in sediments of Miyun reservoir

The chemical forms, spatial distribution and sources of As, Hg, Cd, Pb and Zn in sediments of the Miyun reservoir were studied. The results of sequential extraction demonstrate that most of As, Pb and Zn were bound to the residual fraction, Hg was associated with the sulfide fraction while Cd was associated with the carbonate fraction and the residual fraction. On the vertical profiles the concentrations of the heavy metals in total and each fractions mostly decreased with increasing depths in sediments, suggesting that the heavy metals input from the upstream watershed increases yearly. Summation of the residual fraction, the sulfide fraction and the carbonate fraction accounts for 60.03%―85.60% of the total heavy metal contents in the sediments, which represent the geochemical background values of the elements and relate closely to soil erosion. Results of the main factor analysis show that most sediments of the reservoir come from the upstream soil erosion, the point source pollution and domestic waste. Moreover, the microbial activities taking place on the sediment-water interface are also one of the major factors to cause the increasing content of the organic matter fraction and the iron-manganese oxide fraction. Environmental change of the reservoir water could make the removability of the heavy metals increase, leading to the increase of their concentrations in pore water in sediments, and imperiling water quality of the reservoir.     

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.     

Sr isotope evolution during chemical weathering of granites -- impact of relative weathering rates of minerals

The Sr isotopic systematics in the weathering profiles of biotite granite and granite porphyry in southern Jiangxi Province were investigated. The results showed that during the chemical weathering of granites, remarked fractionation occurred between Rb and Sr. During the early stages of chemical weathering of granites, the released Sr/Si and Sr/Ca ratios are larger than those of the parent rocks, and the leaching rate of Sr is higher than those of Si, Ca, K, Rb, etc. Dynamic variations in relative weathering rates of the main Sr-contributing minerals led to fluctuation with time in 87Sr/86Sr ratios of inherent and released Sr in the weathering crust of granite. Successive weathering of biotite, plagioclase and K-feldspar made 87Sr/86Sr ratios in the weathering residues show such a fluctuation trend as to decrease first, increase, and then decrease again till they maintain stable. This work further indicates that when Sr isotopes are used to trace biogeochemical processes on both the catchment and global scales, one must seriously take account of the prefer-ential release of Sr from dissolving solid phase and the fluctuation of 87Sr/86Sr ratios caused by the variations of relative weathering rates of Sr-contributing minerals.     

“空矿”溶液及废弃乙酸丁酯用于萃取原子吸收法测金

本文提出了一个用“空矿”溶液及再生处理过的废弃乙酸丁酯测定金的方法。运用该方法测金 ,提高了灵敏度和准确度 ,改善了标准曲线的线性关系 ,同时也提高了乙酸丁酯的利用率。     

Summer weather characteristics on the Grove Mountain of East Antarctica

The summer weather characteristics of the Grove Mountain, East Antarctica, are presented based on the data obtained by Chinese National Antarctic Expedition (CHINARE) in January 1999. The result shows that the pattern of daily variation of temperature and the prevailing wind direction in Grove is similar to that of Zhongshan Station. However, the daily range of temperature and strong wind frequency are much higher than those of Zhongshan Station. The change of wind direction is close to the weather system that impacted the Grove Mountain. The warm and wet air from northern parts often causes the precipitation. The clear weather appears when controlled by eastern winds in January.     

沙坡头没蒿和柠条叶片δ13C 和 N 含量的季节变化特征

通过对腾格里沙漠东南缘沙坡头人工固沙区油蒿和柠条叶片稳定碳同位素分辨率（△）和N 含量的测定，研究了不同种植方式下油蒿和柠条叶片△ 和 N 含量的季节变化及其关系。结果表明：在不同种植方式下，两种植物的△ 与 N 含量在不同月份之间均存在显著差异。油蒿叶片 △ 极显著高于柠条的：在不同种植方式下，油蒿单种下 △ 显著高于混种，柠条则反之。 油蒿叶片 N 含量极显著低于柠条的：不同种植方式下柠条叶片 N 含量无显著差异，而单种油蒿叶片 N 含量则显著低于混种。在 △ 与 N 含量的关系中，柠条叶片 △ 与 N 在两种生境、单种和混种下均极显著正相关，雨明柠条叶片 N 含量可以作为其 △ 与 N 含量的季节变化及其关系在不同微生境有所差异。     

川东北地区海相烃源岩中单质硫的定性与定量分析

利用定性与定量分析手段,研究了川东北地区各类海相烃源岩中的单质硫及其地球化学特征。定性分析表明,该区海相烃源岩中的单质硫具有八硫环状结构和六硫状环结构两种晶体构型,由S8和S6两种同素异形体组成,其中S8具有相对较高的丰度。定量分析表明,该区海相烃源岩中的单质硫含量为0.91×10-6～375.88×10-6,具有很宽的分布范围,并且随着烃源岩分布区域、地层时代以及岩性的不同而发生明显变化,表现出强烈的非均质性分布特征。该区海相烃源岩中单质硫含量与有机碳含量之间存在正相关关系,说明单质硫主要发育在富有机质沉积的层段中。通过单质硫含量与总硫含量对比分析,间接证明了川东北地区各类海相烃源岩中赋存有丰富的有机含硫化合物。     

江苏南京市城市湿地滨水空间特点研究

城市湿地是近年湿地景观研究的热门话题。南京市地处长江下游,市内河湖众多。以南京主要城市湿地如玄武湖、秦淮河等的滨水空间为研究对象,分析其护岸、植物构图等方面的特征,以期探索出更为科学合理的滨水空间模式,为南京及其它城市的城市湿地滨水空间规划建设提供一定的参考。     

应用遥感影像制作矿区大比例尺地形图

本文在专业的遥感和地理信息系统软件平台支持下,利用Aster立体像对和IKONOS高分辨率遥感影像分别提取矿区地形信息和地物信息,结合矿区的实际特点,参照地形图制作规范对矿区大比例尺地形图的制作进行了分析和探讨,结果表明利用遥感影像进行矿区大比例尺地形图制作不但周期短、速度快、时效性强,而且精度完全能够满足生产需要,是一种实用可行的方法。