A data screening approach to confirming a target mineral is chlorite using EPMA and LA‐ICPMS data

Abstract

Applying machine learning techniques to large datasets of in situ analyses has been proven to be a powerful tool in Earth Sciences. However, problems may arise when dealing with minerals such as chlorite, that exist as a solid solution rather than a single, stoichiometric ideal. It can be difficult to determine whether the variations in major element concentrations are due to compositional difference in the mineral of interest or due to sampling of the surrounding mineral phases in addition to the mineral of interest during the analyses. If the latter, interpretations of the results would be complicated, misled or even spurious. Here we present a method to identify chlorite based on the major and minor element content, from both LA‐ICPMS and EPMA data. Further we present a dataset of 3,317 analyses of chlorite and have shown that 7.4% of these analyses include significant quantities of non‐chlorite material.

Chlorite geochemical vectoring of ore bodies: a natural kind clustering approach

“…Chlorite chemistry data was acquired from literature research, ScienceDirect, and GeoScienceWorld. Analyses went through extensive filtering to ensure that they can be confidently considered as chlorite (Freij et al, 2023). After these data were processed and filtered, 1,679 analyses remained from five papers studying five distinct areas: porphyry Cu-Au deposits in the Northparkes District in Australia (Pacey et al, 2020) and the Batu Hijau district in Indonesia (Wilkinson et al, 2015), Cu-Mo deposits in the Superior district of Arizona (Cooke et al, 2020) and El Teniente in Chile (Wilkinson et al, 2020), and a Cu-Mo-W deposit in Tongshankou, China (Chu et al, 2020).…”

“…Data was filtered after the methods of Freij et al (2023), and a summary of the process is provided here. The first step in processing the data was to determine whether the data acquired from literature sources was chemically consistent with chlorite.…”