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

对巴西地盾中分布的碳酸盐-碱性杂岩进行了矿物调查和采集，分析了矿物的产状、结构、化学成分或晶体结构之间的关系。稀土元素的富集是配合物的特征。（1）在圣保罗以北200 km的波科斯德卡尔达斯地区进行了调查。(a)在塞罗特和布里吉达斯采集到一种称为“钙硅石”的岩石，其中含有大量的Zr，可形成锆石或斜锆石。斜锆石具有胶体状结构，表明Zr在水溶液中以次生矿物形式富集。(b)在Morro do Ferro，观察到了特别富含铁的侵入岩。这些岩石主要由磁铁矿组成。很明显，土壤中富集了Th等放射性元素，这可能是由碱性岩石的绢云母化提供的， ...更多信息 主要成分是辉石。(c)辉石是在不同点观察到的碱性岩石的主要成分，或形成该地区周围的索马的辉石，粒度从细到粗不等。这意味着这些岩石的形成方式多种多样。(2)在目前对位于圣保罗以北400公里的Tapira和阿拉克萨地区的调查中，在磷、钛和铌矿床下面发现了一个新的非风化复合体。这样一个新鲜的复杂是最重要的研究组成矿物物种。此外，在钙钛矿中通过SEM观察到了显示从钙钛矿到钙钛矿的逐渐变化的结构，这被认为是风化的过渡阶段，或者还鉴定出稀有矿物，如Ca-Zr-Ti氧化物或含Al的钙磷酸盐。(3)在圣保罗以北600公里的卡塔劳地区，有一些生产磷酸钙肥料的矿山。此外，大量的稀土元素作为风化产物富集在土壤中，因此这些矿山的进一步开发需要其组成矿物的基础数据。我们从矿业公司GOIASFERTIL那里获得了大量的土壤钻孔岩心进行分析。(4)在圣保罗西南200公里处的Jakiranga附近的卡贾蒂地区，收集到了最新鲜的复合体标本。围岩主要由富含Ti的辉石组成，被称为“jujiirangite”。上述岩石和矿物最有价值，因为在日本的地质环境中没有发现这样的标本。持续的，更详细的研究是必要的，以解释这种复合物形成的起源。少

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