Modelling the base of submarine permafrost in the Canadian Beaufort Sea from seismic data and the depth of the gas hydrate stability zone
Bibliographic record
Abstract
During the last 1 Ma in the Canadian Arctic, permafrost and permafrost-associated gas hydrates formed extensively due to mean annual subaerial temperatures of approximately -20°C. Following the last glaciation, a marine transgression occurred and former terrestrially exposed shelves became inundated, resulting in present submarine bottom water temperatures around -1°C. Relict submarine permafrost and gas hydrates in the Canadian Beaufort Sea are still responding to this thermal change resulting in their ongoing degradation. Thawing of permafrost and destabilisation of permafrost-associated gas hydrates can release previously trapped greenhouse gases and can lead to even further gas hydrate dissociation with important implications for the global climate. However, both the extent of the submarine permafrost and the permafrost-associated gas hydrates are still not well known. In this study, we use marine multichannel seismic data to model the base of permafrost from the depth of the base of the gas hydrate stability zone. From this depth, we estimate the theoretical gas hydrate dissociation temperature, which allows us to model the depth of the thermal base of permafrost (0°C isotherm). The base of permafrost we modelled correlates with the lower boundary of a diffuse zone of high diffractivity in seismic data suggesting the presence of ice-bearing permafrost. These results combined show that the base of permafrost still extends close to the shelf edge indicating less permafrost retreat than previously suggested. Our study provides a different approach to accessing the current depth and extent of submarine permafrost on the outermost Canadian Beaufort Shelf.
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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 | 0.008 | 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 | 0.000 | 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) | 0.000 | 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".