The crustal structure of the Alpha Ridge at the transition to the Canadian Polar Margin: Results from a seismic refraction experiment
Bibliographic record
Abstract
[1] The crustal structure of the Alpha Ridge and its connection to the Canadian Polar Margin was studied by a seismic refraction experiment consisting of a 350-km-long line almost perpendicular to the margin and of a 175-km-long cross line on the ridge. Explosive shots spaced 22 km apart were recorded by geophones deployed on the ice and spaced about every 1.5 km. P wave velocity models were developed by forward and inverse modeling of travel times and by tomographic inversion. In proximity to the coast, the models show a 30-km-thick continental crust with velocities from 5.5 to 6.6 km/s. The continent-ocean transition zone is characterized by thinned and intruded continental crust; a high-velocity lower crustal body (7.5 km/s) indicates magmatic underplating. An up to 5-km-thick layer with velocities of 4.7–5.4 km/s can be correlated from the transition zone onto the Alpha Ridge where reflection seismic facies may indicate an upper crustal layer of extrusive volcanics. The transition zone is characteristic for volcanic-style continental margins. The crust on Alpha Ridge consists of the volcanics, a 4-km-thick layer with intermediate velocities of 6.1–6.6 km/s and a lower crustal layer with velocities of 6.8 to 7.3 km/s; Moho depth varies between 26 and 32 km. Velocities on the ridge are similar to other large igneous provinces. The Alpha Ridge and the contiguous Mendeleev Ridge are interpreted to result from interaction between a Cretaceous plume and a seafloor spreading center parallel to the Canadian Polar Margin with the Lomonosov Ridge acting as a shear margin.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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 | 0.000 |
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".