Geology, alteration, mineralization and magmatic evolution of the Southeast Zone (Cu-Mo) and Deerhorn (Cu-Au) porphyry deposits, Woodjam, central British Columbia, Canada
Bibliographic record
Abstract
The Woodjam district is part of the porphyry deposits of Late Triassic to Middle Jurassic age (216–183 Ma) located in the Quesnel terrane in central British Columbia. Porphyry centers include the large Cu-Mo Southeast Zone (SEZ), hosted in the calc-alkalic Takomkane batholith, and the Au-Cu Deerhorn, Megabuck and Takom deposits. The latter are peripheral to the margin of the batholith and are associated with smaller monzonitic bodies of more mafic affinity that intrude and mineralize Nicola Group strata. The Takomkane batholith, host to the SEZ, intrudes and underplates the Nicola Group strata. The main phases include coarse-quartz-monzonite (CQM; 197.48±0.44 Ma) and a later, fine-grained-quartz-monzonite (FQM). Alteration is zoned from intense K-silicate in the center, weaker towards the margins, surrounded by albite alteration at the margins. Mineralization is zoned from chalcopyrite to pyrite-dominated at the margins. The Deerhorn deposit is centered on narrow monzonite bodies with “pencil” geometry and intrudes the Nicola Group volcanic sequence. Main stage of mineralization is hosted in Monzonite-A and is cut by Monzonite-D. Alteration is characterized by intense magnetite and K-silicate in Monzonite-A and adjacent volcaniclastics. Monzonite D displays moderate to weak K-silicate alteration. Mineralization is hosted in banded quartz-magnetite-hematite-chalcopyrite veins in Monzonite A and adjacent volcanic host-rocks. SEZ and Deerhorn intrusive units share geochemical characteristics. The early Takomkane units have higher SiO₂ and incompatible element concentrations, less-fractionated HREEs, negative Eu anomalies, and more radiogenic Nd isotope ratios than the Deerhorn monzonites. The latter are themselves similar to the late SEZ FQM which suggests that the latter and the Deerhorn monzonites are co-magmatic. Differences between alteration and mineralization of both deposits are partially attributed to the depth of emplacement; Cu-Au mineralization at Deerhorn represents a shallower expression of the magmatic hydrothermal system and Cu-Mo mineralization in SEZ represents the deeper segment of the partially contemporaneous system. Geochemical and isotopical affinities between the FQM/Monzonite-A/Monzonite-D intrusions and the plagioclase-phyric andesite of the Nicola Group indicate that these intrusions were partially coeval, and that mineralization in the Woodjam area is tightly connected to the Nicola Group volcanism, as age and chemistry of the rocks are similar.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".