Fingerprinting ore processes in orogenic auriferous systems: insights into metallogenic and exploration implications from argillite-hosted iron sulphide nodules from the Timmins-Matheson gold corridor
Bibliographic record
Abstract
Orogenic Au deposits of the world-class Timmins-Porcupine Au camp in Abitibi and its surroundings are commonly hosted by carbonaceous to non-carbonaceous argillite sequences, which contain Au-rich (less than or equal to10 ppm Au) nodules and concretions; two features widely considered to be diagenetic, but can be equivocal in some highly strained and hydrothermally altered zones. Hence, the goals of this research activity are to (1) fingerprint pyrite of diagenetic or epigenetic origin, (2) constrain factors that control Au uptake in diagenetic pyrite, and (3) determine if early Au enrichment fundamentally influences overprinting orogenic Au mineralization. Pyrite nodules and concretions are generally composed of two textural domains: a core and a rim. The pyrite rims exhibit much more textural complexity than the pyrite cores. Multivariate analysis of trace element data derived from laser ablation-inductively coupled plasma-mass spectrometry reveal a clear geochemical distinction between epigenetic textures (granoblasts, porphyroblasts, idiomorphic overgrowths) and nodules/concretions. In the Timmins-Matheson region, disparate pyrite textures can be discriminated simply by the abundance of thallium. Nodules and concretions also show geochemical attributes that are inherited from the composition of the rock assemblage in which they form. Regardless of their host rocks, the core and rim of the nodules possess different but systematic geochemical signatures, which were constrained with the help of multivariate statistics; Ni, As, Se, Ag, Sb, Au, Pb, and Bi tend to concentrate into the core, whereas Mo and Tl (±Mn) tend to concentrate into the rim. In situ Fe isotope analyses of three pyrite nodules reveal intra-grain variations in delta-56Fe values that range from -3.11 to 0.74 per mille, with 30% of the values < -2.5 per mille which has, in the literature to date, been recorded only in Archean diagenetic pyrite in black shale. The results contribute to a framework that helps improving our interpretation of the genesis of pyrite nodules in deformed and metamorphosed sedimentary rocks, which will ultimately minimize uncertainties related to the interpretation of ore-forming processes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".