Topographic Controls of Nitrogen,Sulfur, and Carbon Transport from a Tolerant Hardwood Hillslope

The lateral down-slope movement of water, NO₃ ^-, NH₄ ⁺, SO₄ ^2-, H⁺ and DOC through an ablation till was examined from 1987 to 1990 for a one hectaresoil catena on a steep hillslope with uniform forest cover at the Turkey Lakes Watershed (TLW), Ontario, Canada. Natural variation in the export of nutrients from the soil profile via soil water to Little Turkey Lake was assessed in relation to nutrient distribution in soil at different topographic positions.Subsurface throughflow exhibited dramatic differences in nutrientconcentrations and fluxes with slope position, largely reflectingthat of the soil horizons through which the water passed. GreaterNO₃ ^-, SO₄ ^2-, and DOC concentrations in subsurface water in the upper, well-drained hillslope were a reflection of enrichment by contact with more acidic, more developed podzols, and more favorable soil physical and biological conditions for NO₃ ^- retention in solution.Nutrient inputs to the lake were strongly influenced by increaseddown-slope transport of water, and increased SO₄ ^2-, N, and C retention in wetter, less-developed podzolic soils that characterize lower slope positions. An understanding of water movement and soil development variation withtopographic position was required to accurately estimate nutrient budgets for steep slopes at TLW.     

地幔端元组分的微量元素地球化学研究综述

结合国内外研究现状，对利用同位素地球化学所确定的地幔端元组分DMM、HIMU、EM1和EM2在微量元素地球化学上的特征进行了综述，并对其成因进行了讨论。     

开滦矿区煤伴生元素土壤地球化学分布模式及成因

唐山开滦煤矿已有百余年的开采史. 经河北平原多目标区域地球化学调查发现,Se、Hg、Mo、Zn和U等微量元素在矿区表层土壤(0～20 cm)中呈异常分布,故利用相关性分析、多元统计分析等地球化学方法,研究Se、Hg、Mo等微量元素土壤地球化学空间分布模式及其成因. 结果表明:以Se元素为代表的土壤微量元素异常与煤田分布范围几乎一致,Se、Hg和Mo等微量元素只在表层土壤富集. 土壤中Se与有机碳(OC)、S等煤炭伴生元素呈高度正相关,R(相关系数)分别为0.88和0.77. 煤炭开采、运输产生的扬尘以及燃煤产生的烟尘是形成Se、Hg等微量元素表层土壤异常分布的主要原因.      

福建德化杨梅地区金矿成矿地质条件和矿床成因

本文分析研究了德化杨梅地区金矿成矿地质条件，矿床主要地质和地球化学特征以及矿床成因等。结果表明，德化杨梅地区是一个金的高背景地球化学场．为成矿提供了物质基础，金矿床、矿点明显地受NE、NW向断裂及其交叉复合部位控制，与成矿有关的侵入岩—次火山岩主要是燕山期的石英闪长岩、花岗闪长斑岩和花岗斑岩；金的矿化类型主要为含金石英脉型、含金石英—硫化物型及破碎蚀变岩型；区内金矿成因类型主要为次火山热液型和岩浆热液型两类。     

农业面源污染特征及治理对策

随着社会经济的发展,中国农业面源污染日益严重,面源污染在很大程度上引起耕地退化,严重影响农产品的质与量.在概述农村面源污染特征的基础上,分析农村面源污染的影响因素,其中化学肥料、农药、畜禽粪便及养殖废弃物、生产和生活污水、生活垃圾等是面源污染的重要因子,从农作技术、水土保持及意识政策等多方面考虑提出农业面源污染的防治措施,并对中国农业面源污染的未来研究进行展望.