Stream sediment geochemistry and automated mineralogy as exploration tools for LCT-pegmatite and granite-related mineralisation : case studies from the Leinster Granite (Ireland) and the Vosges Mountains (France)
2021
Hochschulschrift
Zugriff:
This PhD thesis consists of four original papers and a synthesis chapter investigating the applicability of geochemical pathfinders and automated mineralogical analysis to regional (1 sample per 4 km2) stream sediment surveys. In the context of exploration for rare metal granite and Li-Cs-Ta (LCT) pegmatites, the principal aim of this study was to examine and establish the essential links between geological, geochemical and mineralogical factors and to develop robust tools for commercial stream sediment geochemistry- and mineralogy-based exploration targeting. The concept of applying granite and pegmatite mineralisation-related pathfinder elements and ratios to stream sediments, developed originally for mineral (Kfeldspar, mica, Nb-Ta oxides) and bulk litho-geochemical exploration using outcrop and drill core samples, was tested in a case study using the Geological Survey of Ireland (GSI) stream sediment dataset for the Leinster Granite and adjacent Caradocian Volcanic Belt. Firstly, this study has demonstrated that incompatible (K/Rb) and immobile (Nb/Ta, Zr/Hf) trace element ratios, along with ore-forming elements (Li, Cs, Ta, Nb, Sn, W), provide useful pathfinders in exploration at 1:500,000 scale. Secondly, they can be used to delineate catchment areas within the Leinster Granite that bear evidence of increased magmatic fractionation and hydrothermal alteration characteristic of LCT pegmatite mineralisation. Prospective catchments have been identified in areas with known mineralisation (e.g., eastern flank of the Leinster Granite in the Blackstairs and Northern Units) and where none had been previously detected (e.g., Borris-Fennagh area). Distinctive values of K/Rb (
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Stream sediment geochemistry and automated mineralogy as exploration tools for LCT-pegmatite and granite-related mineralisation : case studies from the Leinster Granite (Ireland) and the Vosges Mountains (France)
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Autor/in / Beteiligte Person: | Steiner, B. |
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Veröffentlichung: | 2021 |
Medientyp: | Hochschulschrift |
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