Lithogeochemical and Stratigraphic Controls on Gold Mineralization within the Metavolcanic Rocks of the Hoyle Pond Mine, Timmins, Ontario
Notice bibliographique
Résumé
The Hoyle Pond gold deposit is hosted in complexly deformed mafic-ultramafic volcanic rocks of the Hersey Lake and Central Formations (Tisdale assemblage) in the Porcupine gold camp, located approximately 15 km northeast of Timmins in the Abitibi greenstone belt. The deposit is hosted within a homoclinal sequence of south-facing stacked volcanic flows of high Mg tholeiitic basalt, basaltic komatiite and komatiite flows, and interbedded high Mg tholeiitic basalt and Fe-rich tholeiitic basalts. The bulk of the gold mineralization was emplaced at lithologic contacts along late shear zones associated with isoclinal folding and thrusting. The mineralization is characterized by micron- to centimeter-sized flakes of free gold or veinlets in quartz-carbonate (dolomite and ferroan dolomite) shear and extension vein arrays. At the mine scale a broad carbonate alteration is evident. Two alteration zones surrounding the veins were mapped at the meter scale: an inner sericite alteration zone composed of sericite (muscovite), fuchsite (Cr muscovite), quartz, arsenopyrite, pyrite, ferroan-dolomite, dolomite, and graphite plus tourmaline, and an outer zone of albite alteration consisting of albite, quartz, ferroan dolomite, and dolomite. Geochemical analyses of 355 samples show that the REE, Zr, Al2O3, TiO2, and Y were largely immobile during alteration and mineralization. CO2, K2O, Na2O, Cr2O3, Rb, As, B, SiO2, and CaO, and locally Fe2O3, FeO, and MgO, were mobile during alteration and mineralization. The chromium enrichment is not primary and is interpreted to have been caused by remobilization from ultramafic rocks during mineralization. In addition, an intense graphite alteration, originally derived from organic matter, probably from sedimentary rocks, and now associated with mineralization, is present in zones that were porous and permeable at the time of mineralization. In common with other mesozonal orogenic gold deposits, gold was likely transported as a thio complex. The Cr enrichment in the wall rock indicates that Cr was mobile, most likely as Cr6+. Because species such as Cr6+ are transported under oxidizing conditions and carbon and Au-HS species are transported under reduced conditions, we suggest that more than one fluid was involved in the mineralization and/or alteration. Mixing between reducing and oxidizing fluids is thought to have reduced Cr6+ to Cr3+, oxidized the organic matter to form graphite, oxidized sulfur to form sulfides, and precipitated Au. This is consistent with the observed para-genesis. Reducing fluids rich in boron, arsenic, carbon, and Au may have been generated from sedimentary rocks (Porcupine assemblage?) at depth and expelled during orogenesis into syndeformation structures within overlying volcanic rocks where they mixed with oxidizing fluids containing Cr, K2O, SiO2, Na2O, and CaO.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».