Geology and lithogeochemistry of the Chester Group and hydrothermal sediments of the Swayze greenstone belt, Superior province, Ontario
Bibliographic record
Abstract
Geological and high-field-strength element (HFSE) relationships for Chester Group felsic volcanic rocks and corresponding sub-volcanic intrusives in the south-east Swayze greenstone belt (SESGB) indicate deposition in an dynamic volcanic-arc tectonic setting, from two separate magmas with calc-alkaline and HFSE-depleted trace element signatures respectively. Chester Group, Yeo Formation rocks have undergone a regionally extensive sericite-quartz (type 1) alteration, involving the loss of 3.25 wt.% Na2O, addition of 12 wt.% SiO2 and 2.2 wt.% K2O, and 13% net mass-gain, indicating water/rock ratios of at least 6. Chlorite-sericite +/- biotite +/- garnet (type 2) alteration at paleo-hydrothermal vent sites was localized along synvolcanic fault structures. Type 2 alteration was accompanied by a loss of 2.44 wt.% Na2O and 8.69 wt.% SiO2, and a gain of 5.90 wt.% Fe2O3, requiring water/rock ratios of at least 432. Hydrothermal sediments or iron formation (IF) within the SGB are composed largely of Si and Fe. Base-metal mineralization in the SESGB and other localities in the SGB is hosted by brecciated hydrothermal sediments, overlain and flanked by, more broadly distributed pelitic IF, enriched in large ion lithophile elements (LILE), Al2O3, TiO2 and HFSE, with distinct Fe2O3/TiO2 versus Al2O 3/(Al2O3 + Fe2O3 + MnO) ratios indicative of mixing with locally derived volcanic material. Well-laminated BIF-type hydrothermal sediments are distributed widely throughout the SGB and are enriched in MnO, depleted in LILE, HFSE and transition elements, and have a wide range of Ce/Ce* values reflecting diverse redox conditions in paleodepositional environments distal to hydrothermal venting. Thermodynamic calculations suggest that hydrothermal fluids responsible for generation of hydrothermal sediments have lower temperatures (250--300°C) but similar pH (~4) to polymetallic volcanogenic massive-sulphide ore-forming fluids.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".