Reimagining Niggli Numbers for modern data applications in petrology and exploration geochemistry
Reimagining Niggli Numbers for modern data applications in petrology and exploration geochemistry
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DOI：
10.1016/j.chemgeo.2023.121915
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发表时间：
2023-12
期刊：
影响因子：
3.9
通讯作者：
Iain McDonald
中科院分区：
文献类型：
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作者：
Iain McDonald
这项研究旨在让地球化学界重新熟悉尼格利数，并探讨保罗·尼格利如何将主要元素表示为等效分子数，并组合成组、总和和比率，这一方案在很大程度上被遗忘了。该方案为解决许多现代地球化学问题提供了简单有效的工具，特别是在需要处理大量数据的情况下降低复杂性和自由度。 Niggli Numbers 为地球化学中长期公认的常数和和数据闭合问题提供了基于比率的方法的替代方法，并提供了一种在简单且一致的化学框架中表示矿物及其关系的方法。 Niggli 计算方案遵循简单的规则，易于自动化，足够灵活，可以容纳缺失的元素或部分分析，并且适用于所有岩石类型。在对最有用的 Niggli 二元图以及 Niggli 空间中常见矿物图进行简短回顾之后，提出了一系列案例研究，以说明该方案在现代岩石学和资源勘探中的潜在应用。这些涵盖以下内容：层状侵入体（例如布什维尔德杂岩）的岩浆演化；岩浆受到围岩的污染；追踪火山成因块状硫化物和斑岩 Cusingle bondMo 矿床的热液蚀变；和沉积层序的化学地层学。
This study seeks to refamiliarize the geochemical community with Niggli Numbers and explore how Paul Niggli's largely forgotten scheme for representing major elements as equivalent molecular numbers that are combined as groups, sums and ratios. This scheme provides simple and effective tools for tackling many modern geochemical problems – particularly to reduce complexity and degrees of freedom where there are requirements to handle large volumes of data. Niggli Numbers provide an alternative to ratio-based methods for the long-recognised problem of the constant sum and data closure in geochemistry and offer a means to represent minerals and their relationships in a straightforward and consistent chemical framework. The Niggli calculation scheme follows simple rules that are easily automated, is flexible enough to accommodate missing elements or partial analyses, and is appropriate for all rock types. Following a short review of the most useful Niggli binary diagrams and where common minerals plot in Niggli space, a series of case studies are presented to illustrate potential applications of the scheme in modern petrology and resource exploration. These cover the following: magmatic evolution of a layered intrusion such as the Bushveld Complex; contamination of magmas by country rocks; tracing hydrothermal alteration in volcanogenic massive sulfide and porphyry Cusingle bondMo deposits; and chemostratigraphy of sedimentary sequences.