Ptarmigan Fiord basement-cover thrust imbricates, Baffin Island, Nunavut
Bibliographic record
Abstract
The rocks at Ptarmigan Fiord on the Hall Peninsula of Baffin Island underwent midcrustal deformation during the formation \nof the Paleoproterozoic Trans-Hudson Orogen. The structural style in the region is dominated by imbricate panels of \nArchean basement orthogneiss and Paleoproterozoic supracrustal strata, interpreted to have been deformed by thick- \nskinned ductile thrusting. Basement rocks comprise amphibolite-facies metatonalite, metagranodiorite, metaquartz-diorite \nand metamonzogranite, and cover rocks comprise amphibolite-facies migmatitic pelitic and semipelitic schist, psammitic \nschist, amphibolite, calcsilicate and quartzite. The S 1a penetrative foliation is variably present in basement rocks and consis- \ntently present in cover rocks, and is defined by alignment of biotite, sillimanite and leucogranite that formed before and dur- \ning the thermal metamorphic peak. The S 1a foliation was deformed by F 1b isoclinal folds with an amplitude of 100 m. These \nstructures are interpreted as forming during a D 1 east-west crustal shortening event. Basement and cover imbrication oc- \ncurred after the thermal metamorphic peak and is interpreted as D 2 thick-skinned ductile thrusting. Ductile thrust faults at \nthe base of seven basement-cover slices are identified on the basis of repetition of units and strain localization, and are inter- \npreted as predominantly south-to-southeast verging on the basis of shear-sense indicators. There are two structural panels of \nD 2 thrust imbricates, one in the northwestern part of the map area and one in the eastern part of the map area. Map-scale \ncrosscutting relationships indicate that the northwestern panel overthrusted the eastern panel on a southeasterly T 2c -di- \nrected thrust fault, following a F 2b folding event that folded the T 2a basement-cover thrust imbricates in the eastern panel. \nThe Ptarmigan Fiord area contains a world-class exposure of thick-skinned structures as they are spectacularly delineated \nby belts of distinctive grey-weathering Archean basement rocks and brown- to black-weathering Paleoproterozoic supra- \ncrustal rocks.
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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 | 0.001 | 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) | 0.001 | 0.001 |
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".