The origin of base metal indicator minerals from till and stream sediment samples: constraints from mineral chemical and S-Pb isotope geochemistry
Base metal indicator minerals recovered from till and stream sediment samples in the southern Northwest Territories were studied to determine their potential origins. Major and trace element geochemistry and S- and Pb-isotopes were used to determine whether these indicator minerals were derived from...
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
Memorial University of Newfoundland
2022
|
| Subjects: | |
| Online Access: | https://research.library.mun.ca/15620/ https://research.library.mun.ca/15620/1/thesis.pdf |
| Summary: | Base metal indicator minerals recovered from till and stream sediment samples in the southern Northwest Territories were studied to determine their potential origins. Major and trace element geochemistry and S- and Pb-isotopes were used to determine whether these indicator minerals were derived from known mineralised bedrock sources or if they were from undiscovered mineral occurrences within the southwestern Northwest Territories, a region with very little previous mineral exploration and thick Quaternary cover. The geochemical and isotopic composition of sphalerite grains indicates derivation from low-temperature (T<250°C) sources consistent with Mississippi Valley-style mineralisation, yet distinct from known nearby mineral occurrences. Galena grains also have geochemical signatures indicative of derivation from low-temperature mineralisation; however, Pb-isotopic data, and previous provenance studies, indicate they were not from the Pine Point deposit or other known mineral occurrences and together with sphalerite represent potentially undiscovered Zn-Pb mineralisation in this area. The geochemical and δ³⁴S compositions of chalcopyrite grains suggest that they were likely derived from low-temperature sources, such as sediment-hosted Cu, and/or kipushi-type deposits. Arsenopyrite grains have δ³⁴S signatures similar to that of igneous sources (i.e., δ³⁴S = ±3‰), the only source of which would be fluids from Canadian Shield basement rocks, remobilized along basement faults in the region. |
|---|