The edge of northwestern North America at ∼1.8 Ga
Bibliographic record
Abstract
The ∼1.80 Ga edge of the northwestern North American craton is buried beneath Phanerozoic and Proterozoic rocks of the Western Canada Sedimentary Basin and the adjacent Cordillera. It is visible in more than eight deep seismic reflection profiles that have images of west-facing crustal-scale monoclines with up to 1520 km of vertical relief, and it produces regional isostatic gravity anomalies that can be followed for more than 1500 km along strike. The deep reflection profiles include two major transects of Lithoprobe (southern Canadian Cordillera transect and Slave Northern Cordillera Lithospheric Evolution (SNORCLE) transect) and industry profiles that are strategically located to provide depth and geometry constraints on the monoclines. The isostatic anomalies mark the density transition from Paleoproterozoic and older crystalline rocks of the Canadian Shield to less dense supracrustal rocks of westward-thickening late Paleo proterozoic and younger strata. These gravity anomaly patterns thus provide areal geometry of crustal structure variations along strike away from the depth control provided by the seismic data. Although many of the monoclines follow the Fort Simpson geophysical trend along the Cordilleran deformation front, isostatic anomalies near Great Bear Lake delineate a northeast-striking region of low values that may coincide with a failed rift arm or the southern margin of a large basin. The monoclines are interpreted as a series of en echelon structures that probably formed as a result of lithospheric extension at about 1.801.70 Ga following terminal accretion of the Paleoproterozoic Wopmay Orogen.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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 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".