巴西Paraná和Bahia地区滑石矿床的地质特征与成因模式     

Antonio Carlos GONDIM  蒋少涌 《岩石学报》2004,20(4)

本文总结了巴西两个最重要的滑石产地,Parana和Bahia区中滑石矿床的地质特征,并探讨了这些矿床的可能成因。巴西的滑石在世界滑石储量与产量中占有十分重要的地位。巴西Parana和Bahia区的滑石矿主要产于前寒武纪地体中。尽管该区的滑石具有不同的地质产状,与变质火山岩和变质沉积岩共生的滑石最为重要。其他类型的滑石,如与镁铁质-超镁铁质岩共生的、在花岗岩与白云质大理岩接触带的、在花岗岩体中呈包体或顶垂体状的、则相对不重要。在巴西与岩浆活动有关的滑石矿化主要发生在前寒武纪(Bahia区)和白垩纪(Parana区)。滑石的成因模式主要有两类:一为与岩浆热液有关的热液交代成矿模式,另一是起源于盆地热卤水的变质流体交代成矿模式。其中后一种成因模式可用来解释巴西的大多数大型滑石矿床,同时也适用于其他地区,如中国辽宁和乌拉尔南部的滑石成矿。  相似文献   

“巴西”一节的教学设计     

施洁亢 《地理教学》2005,(2):28-29

巴西是南美洲最重要的国家，无论是自然环境还是人氛围都是极具特色，同时也是如何协调人地关系的一个范例，所以本节在初中地理中具有重要的地位。如果按传统的教学方法，对教材内容一一讲读，显然有些八股。因此，在教学设计中我尝试引入了综艺节目的一些环节，再配以多媒体，以激发学生求知兴趣，促使学生主动思考，提高课堂教学效果和效率。  相似文献   

秘鲁和巴西矿产资源管理制度研究     

王瑞生 《国土资源通讯》2007,(21):26-29

秘鲁和巴西是世界上矿产资源较为富集的国家,是南美洲的矿业大国,中国每年都与这两个国家有巨大的矿产品进口贸易,特别是铁矿和铜矿。通过对两国矿业的考察以及与矿产资源管理的政府官员会谈,进一步了解了秘鲁、巴西的矿产资源管理制度、  相似文献   

广西种植巴西旱稻单季再生稻的适播期分析   总被引：1，自引：0，他引：1  

廖雪萍  何燕 《广西气象》2006,27(1):39-41

根据巴西早稻IAPAR对气候条件的基本要求，采用广西86个气象观测台站1961～2000年气候资料，从热量、水分条件两个方面对广西种植巴西早稻单季再生稻的适宜播种期进行统计分析，得出结论并提出建议，为广西发展巴西早稻再生稻生产提供决策参考。  相似文献   

Possibilities of exchanging know-how, scientific partners and information between China Society of Geochemistry and Brazilian Association of Geochemistry-SBGq     

Carlos Bandeira Luiz Antonio Trindade 《中国地球化学学报》2006,25(B08):59-59

The Brazilian Society of Geochemistry--SBGq founded in 1985, is located at Rio de Janeiro, Brazil, having more than 300 affiliates that represent most of the principal Brazilian universities. The main SBGq way of divulgation is an international magazine-Geochimica Brasiliensis and a site： www.sbgq.org.br/. Regular meeting of SBGq is realized in each two years in odd years The last meeting it has been realized together the Geochemistry of Portuguese Language Countries and Geochemistry Symposium of the MERCOSUL countries （Argentina, Brazil, Paraguay and Uruguay）. During the even years are realized specific meeting as Environmental Geochemistry in Tropical Countries. The SBGq is associated with other Brazilian scientific societies as Latin American Association of Organic Geochemistry--ALAGO. During its existence the SBGq has published approximately 3000 papers related to the environment, lithogeochemistry, isotopes, surface geochemistry, organic geochemistry, coastal environmental geochemistry, secondary environments, hydrogeochemistry, exploration geochemistry, magmatic geochemistry, rare earth geochemistry, geochemistry of carbonations, biogeochemistry, mineral geochemistry, geochemistry vs. geochronology and geochemistry of precious metals.  相似文献   

Lead in food and soil from a mining area in Brazil and human exposure     

Talita Lammoglia Bemardino R Figueiredo Alice M. Sakuma M.L. Buzzo I.A. Okada C.S. Kira 《中国地球化学学报》2006,25(B08):66-66

During the last century, several lead mines and a metal smelter were in production in the Upper Ribeira Valley, southeastern Brazil. After fifty years of activity, the refinery was shut down in November 1995 and, thereafter the last mines in production were closed. Since 1998, a multidisciplinary research group has carried out an ambitious investigation among the population of five municipalities in the Ribeira Valley （sampled population of 472 children and 523 adults） to assess the human exposure to lead. The highest blood lead levels were found among the population of two villages in the vicinity of the smelter where soil and indoor-dust are highly contaminated. During the present study, the lead contents of several food species that are part of local population diet were investigated. Greens, vegetables, corn, chicken eggs and cow milk, were sampled in two occasions, July 2004 and February 2005. The analytical procedures included burning of organic matter, pre-concentration of lead and, finally, determination by AAS using background correction. The quantification limit was 0.05 μg/g Pb. Soil samples were also collected and analyzed by X-ray fluorescence spectroscopy with a quantification limit of 2 μg/g Pb. The results are very impressing since 100% of greens, vegetables and eggs yielded lead concentrations exceeding the upper limits established by Brazilian regulations whereas milk and maize samples presented lead contents below the regulated limit of 0.05 μg/g Pb. Lead concentrations in soil varied between 156 and 1292 μg/g Pb, resembling the results of previous studies and far exceeding the threshold of 200 μg/g Pb indicated as the intervention value. Lead contents in some species vary consistently with lead concentrations in soils, however, other factors may account for the bioavailability of lead and its intake by plants, like the soil pH, its cationic exchange capacity, clay and organic matter contents, characteristics of the plant species itself, climate, among others.  相似文献   

Origin of high fluoride contents in groundwater of the Santa Maria Formation, Guarany Aquifer System, southern Brazil     

Ari Roisenberg Maria Paula C. Marimon Antonio P. Viero 《中国地球化学学报》2006,25(B08):121-121

Fluoride anomalies （up to 11 mg/L） have been detected in the porous confined Santa Maria Aquifer （Guarany Aquifer System） in the central region of Rio Grande do Sul State, southern Brazil, leading to endemic fluorosis. Two hypotheses are investigated concerning the fluoride origin： contamination by long-term phosphate-fertilizer application due to extensive tobacco plantation or lithogeochemical affiliation from regional rocks. The results are discussed based on statistical and geochemical modeling and stable isotope data of water, nitrate and sulfate. Field monitoring of phreatic and confined aquifer during two years and laboratory leaching and retention experiments were performed. Regional statistical analysis （factorial and cluster analysis） on the basis of 350 wells discriminates four different hydrochemical groups in the confined aquifer, considering magnesium, calcium bicarbonate, sodium chlorinate and sodium bicarbonate as specific parameters. The last two groups reach higher fluoride contents and represent deeper aquifer levels where geochemical modeling shows carbonates （calcite and dolomite） are of super-saturation. The laboratory experiments confirmed that local soils with high CTC and aluminum contents （Udults） represent an efficient geochemical barrier, preserving the aquifer from fluoride contamination and supporting remediation strategies for fluoride removal. δ^18O and δD groundwater data and the local meteoric water line （LMWL） indicate that local precipitation is the main groundwater recharge source in the area.  相似文献   

“巴西”一课的教学反思     

盛丽芬 《地理教学》2006,(3):24-27

上海市二期课改的初中地理教材在“区域地理”的编写上有了重大的变化，安排了不同尺度的区域作为“自主学习”的内容，其主要目的是使学生学会学习和研究区域地理的基本方法。然而，有些教师仍倾向以“先自然后人”的八股式进行国家地理的教学，这种“八股”式教学的熏复，势必削弱学生学习地理的兴趣。笔在教学实习过程中对此颇有感触，现将“巴西”一课教学中的反思和改进，与大家探讨磋商。  相似文献   

桑巴舞成全了巴西足球     

《地理教学》2006,(7):47-47

近日，日本学研究发现，巴西足球的强大不仅在于拥有丰厚的足球土壤、才华横溢的名星球员，而热情豪放、动感十足的桑巴舞更为巴西足球的长盛不衰做出了“突出贡献”。  相似文献   

揪出南寒北旱的"元凶"     

汤家礼 《海洋世界》2011,(2):1-1

2010年刚刚结束不久,全球很多地方都呈现出灾害的征兆,这可真是一个让人不太开心的消息.从去年12月底到今年初以来的不到一个月时间内,澳大利亚、斯里兰卡和巴西先后发生罕见洪灾.根据以往的经验,人们不免将其与"拉尼娜"这种极端天气现象联系起来.  相似文献