The Santa Fé Ni-Co deposit is a major undeveloped lateritic deposit located in the Goiás State of Central Brazil. The deposit comprises two properties that together have indicated resources of 35.7 million tonnes (Mt), grading 1.14% Ni and 0.083% Co, and inferred resources of 104.3 Mt at 1.03% Ni and 0.054% Co. The laterite was derived from Late Cretaceous alkaline ultramafic lithologies that experienced an initial silicification from Eocene to Oligocene, followed by lateritization and partial reworking in Miocene-Pliocene. The deposit is characterized both by oxide- and phyllosilicate-dominated ore zones. In the former, Ni- and Co-bearing hematite and goethite dominate the supergene mineralogical assemblage, while ore-bearing Mn oxyhydroxides occur as minor components. In the phyllosilicate-dominated horizons the major Ni-carrying phase is chlorite.Multivariate statistical analyses (factor analysis and principal components analysis) conducted on the drill core assay database (bulk-rock chemical analyses) showed that significant differences exist between Ni and Co distributions. The Ni distribution is not controlled by any clear geochemical correlation. This is because the highest Ni concentrations have been measured in the ferruginous and in the ochre saprolite zones, where Ni-bearing minerals (chlorite and goethite) are mostly associated with reworked material and only in a limited way, with zones affected by in situ ferrugination. Cobalt has an atypical statistical distribution at Santa Fé if compared with other laterites, correlated not only with Mn but also with Cr in the majority of the laterite facies. From microchemical analyses on several potential Co-bearing minerals, it was found that the Co-Cr association is related to elevated Co contents in residual spinels, representing unweathered phases of the original parent rock now included in the laterite. This element distribution is atypical for Ni-Co laterite deposits, where Co is normally associated with Mn in supergene oxyhydroxides. In the case of the Santa Fé laterite, the Co concentration in spinels is likely related to magmatic and postmagmatic processes that affected the original parent rock before lateritization, specifically (1) orthomagmatic enrichment of Co in chromite, due to its high affinity to spinels in alkaline melts, and (2) trace elements (i.e., Co, Mn, Ni, and Zn) redistribution during the hydrothermal alteration of chromite into ferritchromite. The Santa Fé deposit represents a good example of how the prelateritic evolution of a parent rock strongly affects the efficiency of Co mobilization and enrichment during supergene alteration. Based on the interpretation of metallurgical test work, a fraction of total Co between 20 and 50% is locked in spinels.

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母岩的岩浆作用对后岩浆作用的演化对红土系统中钴矿运移的影响：以圣菲镍钴矿床（巴西）为例

SantaFéNi-Co矿床是位于巴西中部Goiás州的主要未开发的红土矿床。该矿床包括两处矿产，共表明资源量为3570万吨（Mt），镍品位为1.14％，Co含量为0.083％，推断资源量为104.3 Mt，镍含量为1.03％，Co含量为0.054％。经历了从始新世到渐新世的硅化作用，然后在中新世-上新世进行红土化和部分返工的超镁铁岩性岩性。该矿床的特征是以氧化物和页硅酸盐为主的矿带。在前者中，含镍和含钴的赤铁矿和针铁矿在超基因矿物学组合中占主导地位，而含矿的锰氢氧化物作为次要成分存在。在以页硅酸盐为主的地层中，主要的Ni载运相为亚氯酸盐。对钻芯分析数据库（体岩化学分析）进行的多元统计分析（因子分析和主成分分析）表明，Ni和Co分布之间存在显着差异。 。镍的分布不受任何明确的地球化学相关性的控制。这是因为在铁质和and石腐泥土地区测得的最高Ni浓度是含镍矿物质（绿泥石和针铁矿）与返工材料相关的主要部分，并且受制于原位铁素化的区域非常有限。 。与其他红土相比，钴在圣菲具有非典型的统计分布，在大多数红土相中，钴不仅与锰有关，而且与铬有关。通过对几种潜在的含钴矿物的微化学分析，发现钴铬结合与残余尖晶石中钴含量的升高有关，代表现在包括在红土中的原始母岩的未风化相。对于镍钴红土矿来说，这种元素分布是非典型的，其中钴通常与超氧化物羟基氧化物中的锰相关。在圣塔菲红土中，尖晶石中的Co浓度可能与影响红土化之前原始母岩的岩浆和后岩浆过程有关，特别是（1）铬铁矿中Co在岩浆中的正磁性富集，因为它对尖晶石中的尖晶石具有高度亲和力。碱熔体，以及（2）在铬铁矿热液化为亚铁铬铁矿过程中微量元素（即Co，Mn，Ni和Zn）的重新分布。SantaFé矿床很好地说明了母岩的前岩性演化如何强烈影响超基因蚀变过程中Co的动员和富集效率。根据对冶金测试工作的解释，总钴中有20％至50％的一部分被锁定在尖晶石中。