Synchrotron data - Ryan Petra III (May 2015) - As incorporation in apatite Quick XANES

Spatially resolved chemical speciation by determination of the oxidation state using X-ray absorption spectroscopy is a powerful tool to explore and understand processes in a number of fields such as geology,\r\nmaterial science, catalysis or biology. Using the fluorescence signal, speciation at trace element concentrations becomes feasible. Probing the chemical state at distinct spots or regions of interest rapidly and\r\nrepeatedly using fast X-ray absorption spectroscopy provides an ideal means to study in-situ processes or beam-sensitive samples. An example of the importance of visualizing of the distribution of the oxidation state of a trace element in a geologic application is the distribution of the As oxidation state in arsenic-bearing apatite, which is found in iron-oxide, copper, gold deposits in the Mt Isa inlier. Tracing the origin of chemical zoning and interpreting it in terms of fluid-rock interaction is fundamental to understanding how metals are transported and deposited in these minerals. Further, 3d elements provide a means to understand the behavior of pathfinder elements in resistate minerals associated wit gold mineralization, for example by studying the relationship between the substitution of Ti in rutile with M3+ (such as V) and M5,6+ species (such as W and V) and the variation of the oxidation state of vanadium around the mineralized zones in gold deposits.\r\n\r\nThese experiments will set the stage for fast XANES and EXAFS measurements using the Maia detector providing valuable information about geological mineralization processes. The aim is to investigate different fast scanning XANES methods, varying the order of the XYE axes.\r\n\r\nWe will apply 2D XANES mapping using the energy as the fast scanning axis to map the distribution of oxidation state in geological thin sections. These will provide vital clues to understand mineralization and\r\nalteration processes and how metals are transported and deposited in minerals, and the factors that drive indicator elements in path finder minerals to Gold deposits.\nLineage: Data was produced using the Maia 384 element detector array on the P06 X-ray microprobe beamline of the Petra III Synchrotron, DESY, Hamburg and processed using the GeoPIXE software package.

利用X射线吸收光谱（X-ray absorption spectroscopy, XAS）测定氧化态以实现空间分辨化学形态分析，是地质学、材料科学、催化科学乃至生物学等诸多领域中探索与解析相关过程的强有力工具。借助荧光信号，痕量元素浓度下的化学形态分析成为可能。利用快速X射线吸收光谱，快速且重复地对特定目标位点或区域的化学状态进行探测，为原位过程研究或对光束敏感的样品分析提供了理想手段。在地质应用中，可视化痕量元素氧化态分布的重要性体现在：澳大利亚芒特艾萨断块（Mt Isa inlier）的铁矿、铜矿及金矿矿床中产出的含砷磷灰石，其内部砷的氧化态分布便是典型案例。追溯化学环带的成因并结合流体-岩石相互作用进行解读，是理解金属在这类矿物中运移与沉淀机制的核心所在。此外，三维元素分析可为理解与金矿化作用相关的稳定矿物中的探途元素行为提供途径，例如研究金红石中Ti与M³⁺（如V）、M⁵⁺/M⁶⁺（如W和V）的取代关系，以及金矿矿床矿化带周边钒的氧化态变化规律。

此类实验将为使用MAIA探测器（Maia detector）开展快速X射线吸收近边结构（X-ray absorption near edge structure, XANES）与扩展X射线吸收精细结构（extended X-ray absorption fine structure, EXAFS）测量奠定基础，相关测量可提供有关地质矿化过程的宝贵信息。本研究的目标为探究不同的快速扫描XANES方法，其中将调整XYE轴的扫描顺序。

我们将以能量作为快速扫描轴，开展二维XANES成像测绘，以获取地质薄片中氧化态的分布信息。此类结果将为理解矿化与蚀变过程、金属在矿物中的运移与沉淀机制，以及驱动金矿探途矿物中指示元素变化的相关因素提供关键线索。

数据集谱系：本数据集使用德国汉堡DESY的Petra III同步辐射装置P06 X射线微探针光束线的MAIA 384元素探测器阵列采集，并通过GeoPIXE软件包完成处理。