Metamorphism in Neoarchean Granite-Greenstone Belts: Insights from the Link between Elu and Hope Bay Belts (∼2.7 Ga), Northeastern Slave Craton
Bibliographic record
Abstract
The Elu Link in the northeast Bathurst Block of the Slave Craton, Canada, is composed of variably D1–D3-deformed, low- to medium-grade supracrustal and intrusive rocks connecting the Neoarchean Hope Bay and Elu granite-greenstone belts (∼2.7 Ga). Textural observations and pseudosection modeling show that the primary metamorphic reactions in the supracrustal rocks derived from D1-assisted hydrothermal alteration in albite-epidote hornfels-facies to greenschist-facies conditions. This was followed by one main cycle of prograde, peak, and retrograde metamorphism that variably accompanied D1 and D2 events along a clockwise pressure-temperature (PT) path. The pseudosection for a garnet-bearing orthogneiss whose protolith emplacement occurred before peak metamorphism indicates maximum upper-amphibolite conditions of 6.7 kbar and 710°C, reached during D2 deformation. Thereafter, the orthogneiss followed a counterclockwise PT path showing an increase in pressure (up to 8.7 kbar) during the late stages of D2, which turned into D3 during near-isothermal decompression characterized by retrogression in the greenschist-facies conditions. This evolution of the orthogneiss is evidence that part of the heat budget used for metamorphism in the Elu Link derived from intrusive bodies. However, most pressure and temperature estimates are in the range of 3.5–9 kbar and 500°–660°C, respectively. These PT intervals are indicative of orogenic rather than low-P/T metamorphism. Thermobarometric signatures for low-P/T metamorphism are scarce and likely relate to intrusions postdating peak conditions in the belt.
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 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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".