Studies in Rare-earth and Radioactive Minerals of Pocos de Caldas in Brazil.

巴西波科斯迪卡尔达斯稀土和放射性矿物研究。

• 批准号: 63043014
• 负责人: TOKONAMI Masayasu
• 金额: $ 1.41万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Overseas Scientific Research
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63043014/
• 关键词: Rocks and Minerals in Brazil; Pocos de Caldas; Alkalic Rock; Carbonatite; Rare-earth Mineral; Mineral Texture; Weathered Soil; 燐・チタン鉱床

Survey and collection of minerals were carried out in the carbonatite-alkaline complexes which dot Brazilian shields, so as to analyze the relation among occurrence, texture, chemical composition or crystal structure of those minerals. Concentration of rare-earth elements is characteristic of the complexes. The results of the present research are summarized as follows:(1) Survey in the area of Pocos de Caldas, 200 km north of Sao Paulo.(a) A rock called"caldasite" containing much amount of Zr, which forms zircon or baddeleyite, was collected at Serrote and Brigidas. Particularly, the baddeleyite shows a colloform texture which suggests that Zr is concentrated in secondary minerals from water solution.(b) At Morro do Ferro, intrusive rocks particularly rich in Fe were observed. These rocks are composed chiefly of magnetite. It has become clear that radioactive elements such as Th are enriched in the soil, which is supposed to have been supplied by sericitization of alkalic rocks whose m … More ajor constituent is pyroxenes.(c) Pyroxenes, the main constituent of the alkalic rocks observed at various points or those forming the somma surrounding this area range from fine- to coarse-grained. It means a great variety of formations of these rocks.(2) In the present survey of the area of Tapira and Araxa, which lie 400 km north of Sao Paulo, a fresh non-weathered complex was found below the P, Ti and Nb ore deposits. Such a fresh complex is most important to investigate the constituent mineral species. Besides, a texture showing the gradual change from perovskite to anatase was observed by SEM in glimmerite which is supposed to indicate a transition stage in weathering, or rare minerals such as Ca-Zr-Ti oxides or Al-bearing Ca-phosphates were also identified.(3) In the area of Catalao, 600 km north of Sao Paulo there are some mines yielding Ca-phosphates as fertilizer. Besides, a great quantity of rare-earth elements are concentrated to the soils there as the weathering products, and therefore basic data of the constituent minerals are required for the more development of these mines. We obtained plenty of boring cores of the soils for analysis by the courtesy of the mining company, GOIASFERTIL.(4) In the area of Cajati near Jacupiranga, 200 km southwest of Sao Paulo the most fresh specimens of the complex were collected. The country rock is the one mainly consisting of pyroxene rich in Ti, which is called "jacupirangite".The above-described rocks and minerals are most valuable, since such specimens are not to be found in Japanese geological environments. Continuous,more detailed research is necessary to explain the origin of formation of such complexes. Less

矿物质的调查和收集是碳酸盐 - 阿基林综合体Werech Dot Brazililian Shields Currence，质地，这些矿物质的晶体结构。在圣保罗（A）北部的岩石中，岩石包含大量的Zr，尤其是Zircon或Baddeleyite，baddeleyite显示出colleform纹理的质量磁铁矿。在岩石的岩层中，在岩石的岩石上，在paulo以北400公里从盐盐或Al-barearing Ca磷酸盐中的过渡阶段也鉴定出了从Sao Paulo以北600公里的地区，观察到了钙钛矿到解剖酶的逐渐变化作为世界的土壤，构成的基本数据是更多的矿山发展。 Jacupiranga，Sao Paulo西南200公里，该综合大楼的最新鲜标本主要由富含辉石的岩石组成，这被称为“。在日本地质持续中可以找到，需要更详细的研究来解释这种复合物的形成的起源。