Evidence for an important tectonostratigraphic seismic marker across Canada Basin and southern Alpha Ridge of the Arctic Ocean
Bibliographic record
Abstract
An extensive modern dataset of short-offset seismic reflection profiles coupled with wide-angle reflection and refraction sonobuoy records enable new insights into the crustal types, rifting processes, subsidence history, and sedimentary sequences of Canada Basin, Northwind Ridge, and southern Alpha Ridge. Exceeding 6.5 km in thickness across southern Canada Basin and thinning northward to Alpha Ridge, the sedimentary succession is divided into more than a dozen regional seismostratigraphic units, the oldest of which is informally named the bisque unit. Characterized by anomalously high-amplitude reflections, this unit is of interest since it immediately overlies acoustic basement and may indicate something about the nature of basement and its tectonic history. Along southern Alpha Ridge, including Nautilus Spur, the base of the bisque unit is marked by a prominent angular unconformity that can be traced southward into Canada Basin before becoming obscured by deep burial. The bisque unit appears to be concordant with basement topography and it is clearly offset by faults created during the most recent significant extension of the basin. Distinct onlap of overlying units indicates that extension was accompanied by apparently rapid subsidence and then quiescence. Large basement structures interpreted to be volcanic edifices are immediately overlain and at least partially covered by the bisque unit which might indicate a genetic linkage. On sonobuoy records, two distinct phenomena are observed for the bisque layer: 1) wide-angle reflections and refractions on records distributed widely across the study area; and 2) high amplitude phases of anomalously low apparent velocity across northern Canada Basin and Nautilus Spur. The latter are modelled as converted waves with down-going P-to-S and up-going S-to-P conversions occurring at the bisque layer. This is an important phenomenon since it presents the possibility of estimating Poisson's ratio for crustal layers beneath bisque which would be a valuable constraint in determining crustal types. Though not yet sampled, the bisque unit is interpreted to consist of highvelocity siliceous oozes interbedded with hemipelagic and pelagic sedimentation. In Canada Basin, it may correlate with mid-to-upper Cretaceous tuffs of the Christopher and Kanguk formations found on Banks and Prince Patrick islands. The unit may become increasingly younger northward over Alpha Ridge.
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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) | 0.000 | 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".