The role of inland ice dynamics in controlling the variable maximum extent of the Laurentide Ice Sheet off southeastern Baffin Island
Bibliographic record
Abstract
Reconstructions of the maximum extent and dynamics of the Laurentide Ice Sheet (LIS) during the Last Glacial Maximum (LGM) are needed for understanding how marine‐based ice sheets will respond to modern climate change. The partitioning of ice masses and the location of dominant ice flows within the LIS are broadly known at regional scales, but their influence on the marine‐based maximum extent of the ice sheet remains poorly constrained. Here, we provide evidence for the maximal extent of the LIS margin during the LGM in the Broughton and Merchants cross‐shelf troughs off southeastern Baffin Island based on newly acquired sea floor geomorphology data. Grounding‐zone wedges (GZWs), moraines and ice‐stream bedforms within the Merchants cross‐shelf trough delimit the maximum extent of the LIS in this sector to near the mouth of the modern fjords. Two lateral moraines, mega‐scale glacial lineations (MSGLs), and iceberg scours also indicate the presence of an ice shelf extending beyond the former grounding line. In Broughton Trough, the maximum extent of the LIS is interpreted from the distribution of MSGLs and iceberg scours. The presence of sticky spots near the shelf edge may have played a role in subglacial flow and thus glacier behaviour. The difference in ice extent between the two nearby troughs is attributed to partitioning of the LIS between ice flowing from the Penny Ice Cap into Broughton Trough and ice from local alpine glaciers flowing into Merchants Trough. In addition, the presence of a dominant ice flow south of the Cumberland Peninsula may have drained ice masses of Cumberland Peninsula towards the south and caused minimal expansion in Merchants Trough to the north. These results provide a clearer understanding of the relationship between ice‐sheet extent along continental margins and inland 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".