Integrating Gravity, Magnetic, and Magnetotelluric Data Over Devon Ice Cap, Canadian Arctic, to Investigate the Subglacial Geology
Bibliographic record
Abstract
Abstract The subglacial geology beneath Devon Ice Cap (DIC) is not well understood. An airborne radar study published in 2018 suggested the presence of a hypersaline, subglacial lake beneath DIC where geologic modeling suggested that the source of the brine was an underlying evaporite‐rich sedimentary unit. However recent surface based seismic and electromagnetic data have revealed the absence of subglacial water beneath the center of DIC. Continued studies of this subglacial environment require knowledge of the sediments and bedrock beneath the ice. In this study we combine previously published geology and geothermal studies with new surface‐based magnetotelluric, airborne gravity and aeromagnetic data, to investigate the subglacial geology under DIC. The integrated results show that beneath the center of DIC there is likely a frozen sedimentary unit (3,000–6,000 Ωm) overlying unfrozen crystalline basement rocks of the Canadian shield (400–2,000 Ωm), at depths of 1,500 m–2,000 m. This agrees with recent studies of ice dynamics on DIC, where glacier velocities are low (<20 m a −1 ), within the interior regions of DIC implying the ice is dominantly frozen to the bed. Furthermore, relatively low‐density sedimentary rocks (∼2.2 g/cm 3 ) are the likely cause of the gravity low (−50 to −70 mgal) observed in the northeast of the ice cap and could have implications for future ice dynamics.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".