| Title | Stream sediment indicator mineral signatures of the Casino porphyry Cu-Au-Mo deposit, Yukon, Canada |
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| Author | McClenaghan, M B ;
Beckett-Brown, C E; McCurdy, M W; Casselman, S G |
| Source | Economic Geology vol. 118, no. 2, 2023 p. 411-431, https://doi.org/10.5382/econgeo.4970  Open Access |
| Image |  |
| Year | 2023 |
| Alt Series | Natural Resources Canada, Contribution Series 20210144 |
| Publisher | Society of Economic Geologists |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Yukon |
| NTS | 115I; 115J; 115K; 115N; 115O; 115P |
| Area | Casino |
| Lat/Long WENS | -142.0000 -136.0000 64.0000 62.0000 |
| Subjects | sedimentology; geochemistry; stream sediment geochemistry; stream sediment samples; minerals; porphyry deposits; indicator elements |
| Illustrations | tables; location maps; photographs |
| Program | Targeted Geoscience Initiative (TGI-5) Intrusion/Porphyry ore systems - arc-related porphyry systems - time and space |
| Released | 2023 02 15 |
| Abstract | Case studies around porphyry Cu deposits in the glaciated regions of the Canadian Cordillera have identified the indicator mineral signatures of these deposits in till samples and demonstrated that
these are useful methods for porphyry Cu exploration. This study applies the same indicator methods to stream sediment samples around the Casino calc-alkaline porphyry Cu-Au-Mo deposit in the unglaciated terrain of west-central Yukon, Canada. It is
one of the largest porphyry Cu-Au-Mo deposits in Canada and is hosted in Late Cretaceous quartz monzonite and associated breccias. Bulk (8-16 kg) coarse-grained stream sediment samples were collected in creeks around the deposit, nearby porphyry Cu
occurrences and background areas. The Casino deposit has an obvious indicator mineral signature in the <2-mm heavy (>3.2-specific gravity [SG]) and mid-density (2.8- to 3.2-SG) fractions of stream sediments that is detectable at least 18 km
downstream and includes gold, chalcopyrite, tourmaline, molybdenite, sphalerite, jarosite, goethite, and pyrite. In contrast, not all of these mineralogically anomalous samples have corresponding anomalous geochemical signatures in the fine fraction.
The porphyry indicator minerals identified in this study are similar to those reported for glaciated terrain with the addition of molybdenite and secondary minerals. Indicator mineral methods provide physical evidence of nearby mineralization and can
be chemically analyzed to provide insights about the nature of the mineralizing system. Government and exploration surveys could benefit from the addition of indicator mineral methods to routine stream sediment sampling protocols in unglaciated
regions of the Yukon and elsewhere globally where porphyry Cu exploration is conducted. |
| Summary | (Plain Language Summary, not published)
This journal paper describes the results of surficial geochemistry research around the Casino copper deposit in the Yukon. It describes stream sediment
geochemical patterns around this large deposit and makes recommendations for mineral exploration best practices. |
| GEOSCAN ID | 328556 |
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