Magma evolution and PGE mineralization in the Mechanic Settlement Pluton, southern New Brunswick
Bibliographic record
Abstract
The Mechanic Settlement pluton, southern New Brunswick, is a high-level mafic-ultramafic pluton of Late Neoproterozoic age (ca. 557 Ma). Based on surface outcrop and drill core samples, the pluton includes six different lithologic assemblages: peridotitic, olivine-bearing gabbroic, gabbroic, anorthositic, troctolitic, and dioritic, each of which consists of a range of related rock types. Cumulate textures are typically present, and several rock types contain interstitial hydrous silicate minerals, indicating a wet parent magma. The general mineral crystallization sequence in the pluton was olivine and chromite, plagioclase, clinopyroxene, orthopyroxene, and a hydrous mafic silicate mineral (either phlogopite or hornblende). Lithologic assemblages and their constiutent varieties are not continuous between drill holes, and no statistically significant pattern in the stratigraphic succession could be established with the available data. Variation in the mineralogy and chemistry of the rocks is controlled by fractionation of olivine and plagioclase. The Mechanic Settlement pluton, and comagmatic Coldbrook Group basalt (560-550 Ma), is probably of calc-alkaline affinity. Several platinum group element bearing horizons associated with minor sulphide mineralization (pyrrhotite-chalcopyrite-pentlandite) occur in peridotitic rocks, which may have formed during or following magma influx. Based on similarities to the Lac des Iles complex, Ontario, the best potential for exploration for additional mineralization may be in the poorly exposed gabbroic-dioritic western part of the pluton.
 
 Resume
 
 Le pluton de Mechanic Settlement, dans le Sud du Nouveau-Brunswick, est un pluton mafique-ultramafique de haut niveau remontant à l’époque du Néoprotérozoïque tardif (environ 557 Ma). Selon des échantillons de carottes et d’affleurements en surface, le pluton comporte six assemblages lithologiques différents : des assemblages péridotitique, gabbroïque à olivine, gabbroïque, anorthositique, troctolitique et dioritique, qui sont constitués d’un éventail de types de roches connexes. Des textures cumulus sont généralement présentes et plusieurs types de roches renferment des silicates hydratés interstitiels, ce qui signale un magma parental humide. La séquence générale de cristallisation minérale à l’intérieur du pluton comprenait de l’olivine et de la chromite, du plagioclase, du clinopyroxène, de l’orthopyroxène et un silicate mafique hydraté (de la phlogopite ou de la hornblende). Les assemblages lithologiques et leurs divers composants ne sont pas présents sous forme continue entre les puits de forage, et les données disponibles n’ont pas pu permettre l’établissement d’une configuration statistiquement déterminante dans la succession stratigraphique. La variation de la composition minéralogique et chimique des roches est régie par la cristallisation fractionnée de l’olivine et du plagioclase. Le pluton de Mechanic Settlement et le basalte du groupe comagmatique de Coldbrook ont probablement une affinité calcoalcaline. Plusieurs horizons renfermant des éléments du groupe du platine associés à une minéralisation modeste de sulfures (pyrrhotite-chalcopyrite-pentlandite) sont présents dans les roches péridotitiques, qui pourraient s’être formées au cours ou à la suite d’un afflux de magma. À en juger d’après les similarités avec le complexe du Lac des îles, en Ontario, la partie occidentale gabbroïque-dioritique faiblement exposée du pluton pourrait offrir le meilleur potentiel pour l’exploration de minéralisations supplémentaires. [Traduit par la redaction]
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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) | 0.002 | 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".