Petrogenetic insights into the largest volcanic pulse in the Archean Abitibi greenstone belt, Canada: the Stoughton-Roquemaure assemblage
Bibliographic record
Abstract
The Stoughton-Roquemaure (S-R) assemblage represents the largest and most rapidly emplaced (∼3 m.y.) volcanic sequence within the Abitibi greenstone belt, yet much of its petrogenetic history remains unexplored. To address this, we compile 1319 whole-rock geochemical analyses, comprising 1.0% komatiites, 2.6% komatiitic basalts, 37.1% tholeiitic basalts, 0.5% tholeiitic intermediate volcanics, 8.1% medium-Th basalts, 19.1% high-Th basalts, 0.4% low-Zr basalts, 4.2% transitional intermediate volcanic rocks, 17.1% calc-alkaline intermediate volcanic rocks, and 9.9% felsic volcanic rocks. Primary magma estimates for komatiites and tholeiitic basalts reveal two clusters of mantle potential temperatures ( T P ) of 1637 ± 65 and 1575 ± 105 °C, suggesting a mantle plume influence. Fractional crystallization models, under varying pressures and H 2 O contents, explain the evolution of the tholeiitic suite. However, more than half of the S-R samples exhibit transitional to calc-alkaline affinities, modeled as the result of assimilation–fractional crystallization or magma mixing between tholeiitic basalt and a tonalite–trondhjemite–granodiorite-like crustal end-member. The generation of these volcanic rock signatures implies the development of complex crustal magmatic systems. Spatial analysis reveals that these signatures are prevalent in the north whereas ultramafic and tholeiitic rocks dominate central and southern zones, defining a north–south geochemical zonation. This likely reflects rapid ascent through a thinner crust in the south versus enhanced crustal interaction in the north. Our results underscore the interplay between the mantle-derived magmas and crustal architecture in controlling volcanic evolution. These results offer new insights into the geochemical diversity and voluminous magmatism of the S-R assemblage and contribute to our understanding of Archean lithospheric development.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 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".