The volcanic and deformation history, geodynamic setting, and metallogenesis of the Chisel Sequence, Snow Lake, Manitoba, Canada
Bibliographic record
Abstract
The largest Paleoproterozoic VMS district in the world is hosted in the Flin-Flon Glennie \nDomain of the Trans-Hudson Orogen. Most of the VMS deposits occur within the Flin Flon and \nSnow Lake arc assemblages of the Flin Flon belt. The Chisel sequence of the ca. 1.89 Ga Snow \nLake assemblage is host to six economic VMS deposits; however, its deformation history prior \nto ca. 1.86 Ga and its ore-forming volcanic environment are poorly constrained. The Photo Lake \ndeposit occurs within the Chisel sequence and exhibits anomalous Au and Cu enrichment when \ncompared to the other Chisel sequence deposits, but the source of this metal enrichment and its \nstratigraphic position are unknown. \nDetailed field mapping, including lithofacies and structural mapping, was completed at 1:2,000 \nscale, with local detailed areas at 1:100 or 1:200 scale. Core from 20 Hudson Bay Exploration \nand Development (HBED) drill holes were re-logged and an additional 39 drill holes were \nexamined using whole-rock geochemistry and drill logs provided by HBED to trace the extent of \nunits. Eighty-two outcrop samples and 65 drill core samples, including 32 sulfide samples, were \nanalyzed for whole rock major and trace element geochemistry. Eight of the outcrop samples \nwere also analyzed for whole rock Nd, Hf, and Pb isotopes. Scanning electron microscopy \nprovided the semi-quantitative compositions of mineral phases in least altered and altered \nsamples, and quantitative mineral chemical data for pyrite and pyrrhotite were acquired using an \nelectron microprobe. Trace element maps were produced by laser ablation inductively coupled \nplasma mass spectrometry (LA-ICP-MS) for individual pyrite grains in four of the sulfide \nsamples. \nDetailed field mapping, re-logging of selected drill holes, and whole rock geochemistry \ncompleted in this study indicate: 1) the volcanic rocks of the Snow Lake assemblage underwent a \nfolding and thrusting event prior to 1.86 Ga due to intraoceanic accretion or early accretion to the \nAmisk collage; 2) with the exception of the Threehouse unit, the entire Upper Chisel sequence \nrepresents folded and thrust-repeated Lower Chisel sequence strata; 3) the Chisel sequence VMS \ndeposits, including the Photo Lake deposit, formed within a single time-stratigraphic ore interval \nduring a protracted arc-rifting event; 4) Au enrichment in the Photo Lake deposits is syngenetic \nand can be attributed to a magmatic input; 5) the Anderson VMS deposits formed during \nwidespread arc rifting, whereas the Chisel VMS deposits formed during localized extension \nabove a magma chamber in the extended arc.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".