Serpentine soils and ultramafic laterites develop over ultramafic bedrock and are important geological materials from environmental, geochemical, and industrial standpoints. They have naturally elevated concentrations of trace metals, such as Ni, Cr, and Co, and also high levels of Fe and Mg. Minerals host these trace metals and influence metal mobility. Ni in particular is an important trace metal in these soils, and the objective of this research was to use microscale (µ) techniques to identify naturally occurring minerals that contain Ni and Ni correlations with other trace metals, such as Fe, Mn, and Cr. Synchrotron based µ-XRF, µ-XRD, and µ-XAS were used. Ni was often located in the octahedral layer of serpentine minerals, such as lizardite, and in other layered phyllosilicate minerals with similar octahedral structure, such as chlorite group minerals including clinochlore and chamosite. Ni was also present in goethite, hematite, magnetite, and ferrihydrite. Goethite was present with lizardite and antigorite on the micrometer scale. Lizardite integrated both Ni and Mn simultaneously in its octahedral layer. Enstatite, pargasite, chamosite, phlogopite, and forsterite incorporated various amounts of Ni and Fe over the micrometer spatial scale. Ni content increased six to seven times within the same 500 µm µ-XRD transect on chamosite and phlogopite. Data are shown down to an 8 µm spatial scale. Ni was not associated with chromite or zincochromite particles. Ni often correlated with Fe and Mn, and generally did not correlate with Cr, Zn, Ca, or K in µ-XRF maps. A split shoulder feature in the µ-XAS data at 8400 eV (3.7 Å-1 in k-space) is highly correlated (94% of averaged LCF results) to Ni located in the octahedral sheet of layered phyllosilicate minerals, such as serpentine and chlorite-group minerals. A comparison of bulk-XAS LCF to averaged µ-XAS LCF results showed good representation of the bulk soil via the µ-XAS technique for two of the three soils. In the locations analyzed by µ-XAS, average Ni speciation was dominated by layered phyllosilicate and serpentine minerals (76%), iron oxides (18%), and manganese oxides (9%). In the locations analyzed by µ-XRD, average Ni speciation was dominated by layered phyllosilicate, serpentine, and ultramafic-related minerals (71%) and iron oxides (17%), illustrating the complementary nature of these two methods.

中文翻译：

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利用微聚焦X射线荧光，衍射和吸收，对蛇纹石（超红壤）表层土中微米级的自然镍形态进行分析。

蛇纹岩土壤和超镁铁质红土在超镁铁质基岩上生长，从环境，地球化学和工业的角度来看都是重要的地质材料。它们具有自然提高的痕量金属（例如Ni，Cr和Co）浓度，以及高水平的Fe和Mg。矿物含有这些微量金属并影响金属的迁移率。尤其是，镍是这些土壤中一种重要的痕量金属，本研究的目的是使用微米级（µ）技术鉴定天然存在的矿物质，其中含有与其他痕量金属（如铁，锰和铬）相关的镍和镍。 。使用基于同步加速器的µ-XRF，µ-XRD和µ-XAS。Ni通常位于蛇纹石矿物（如蜥蜴石）的八面体层以及其他具有相似八面体结构的层状层状硅酸盐矿物中，如绿泥石类矿物质，包括斜绿石和硅铁矿。镍还存在于针铁矿，赤铁矿，磁铁矿和水铁矿中。针铁矿中存在蜥蜴石和蛇纹石，其尺寸为微米级。蜥蜴石同时在其八面体层中集成了Ni和Mn。在微米的空间尺度上，顽辉石，辉石，硅铁矿，金云母和镁橄榄石掺入了各种数量的Ni和Fe。在相同的500 µm µ-XRD剖面上，镍铁矿和金云母中的镍含量增加了6至7倍。数据显示为8 µm空间尺度。Ni与亚铬酸盐或亚铬酸锌颗粒无关。Ni通常与Fe和Mn相关，在µ-XRF图中通常与Cr，Zn，Ca或K不相关。µ-XAS数据中8400 eV处有肩裂特征（3。k空间中的7Å-1与位于层状层状硅酸盐矿物（如蛇纹石和绿泥石族矿物）的八面体薄片中的Ni高度相关（平均LCF结果的94％）。通过对X-LCS LCF和平均µ-XAS LCF结果进行比较，可以看出，通过µ-XAS技术可以很好地表示三种土壤中的两种土壤。在用μ-XAS分析的位置中，平均镍形态主要由层状层状硅酸盐和蛇纹石矿物（76％），氧化铁（18％）和氧化锰（9％）决定。在用μ-XRD分析的位置中，平均镍形态主要由层状层状硅酸盐，蛇纹石和与超镁铁有关的矿物（71％）和氧化铁（17％）所主导，说明了这两种方法的互补性。例如蛇纹石和亚氯酸盐类矿物。将XAS LCF块状体与µ-XAS LCF的平均值进行比较，结果表明，通过µ-XAS技术可以很好地表示三种土壤中的两种土壤。在用μ-XAS分析的位置中，平均镍形态主要由层状层状硅酸盐和蛇纹石矿物（76％），氧化铁（18％）和氧化锰（9％）决定。在用μ-XRD分析的位置中，平均镍形态主要由层状层状硅酸盐，蛇纹石和与超镁铁有关的矿物（71％）和氧化铁（17％）所主导，说明了这两种方法的互补性。例如蛇纹石和亚氯酸盐类矿物。通过对X-LCS LCF和平均µ-XAS LCF结果进行比较，可以看出，通过µ-XAS技术可以很好地表示三种土壤中的两种土壤。在用μ-XAS分析的位置中，平均镍形态主要由层状层状硅酸盐和蛇纹石矿物（76％），氧化铁（18％）和氧化锰（9％）决定。在用μ-XRD分析的位置中，平均镍形态主要由层状层状硅酸盐，蛇纹石和与超镁铁有关的矿物质（71％）和氧化铁（17％）所主导，说明了这两种方法的互补性。平均镍形态以层状层状硅酸盐和蛇纹石矿物（76％），氧化铁（18％）和氧化锰（9％）为主。在用μ-XRD分析的位置中，平均镍形态主要由层状层状硅酸盐，蛇纹石和与超镁铁有关的矿物（71％）和氧化铁（17％）所主导，说明了这两种方法的互补性。平均镍形态以层状层状硅酸盐和蛇纹石矿物（占76％），氧化铁（占18％）和氧化锰（占9％）为主。在用μ-XRD分析的位置中，平均镍形态主要由层状层状硅酸盐，蛇纹石和与超镁铁有关的矿物（71％）和氧化铁（17％）所主导，说明了这两种方法的互补性。