Glacial advance, occupation and retreat sediments associated with multi‐stage ice‐dammed lakes: north‐central Alberta, Canada
Bibliographic record
Abstract
Ice sheets that advance upvalley, against the regional gradient, commonly block drainage and result in ice‐dammed proglacial lakes along their margins during advance and retreat phases. Ice‐dammed glacial lakes described in regional depositional models, in which ice blocks a major lake outlet, are often confined to basins in which the glacial lake palaeogeographical position generally remains semi‐stable (e.g. Great Lakes basins). However, in places where ice retreats downvalley, blocking regional drainage, the palaeogeographical position and lake level of glacial lakes evolve temporally in response to the position of the ice margin (referred to here as ‘multi‐stage’ lakes). In order to understand the sedimentary record of multi‐stage lakes, sediments were examined in 14 cored boreholes in the Peace and Wabasca valleys in north‐central Alberta, Canada. Three facies associations ( FAI – III ) were identified from core, and record Middle Wisconsinan ice‐distal to ice‐proximal glaciolacustrine ( FAI ) sediments deposited during ice advance, Late Wisconsinan subglacial and ice‐marginal sediments ( FAII ) deposited during ice‐occupation, and glaciolacustrine sediments ( FAIII ) that record ice retreat from the study area. Modelling of the lateral extent of FA s using water wells and gamma‐ray logs, combined with interpreted outlets and mapped moraines based on Li DAR imagery, facilitated palaeogeographical reconstruction of lakes and the identification of four major retreat‐phase lake stages. These lake reconstructions, together with the vertical succession of FA s, are used to develop a depositional model for ice‐dammed lakes during a cycle of glacial advance and retreat. This depositional model may be applied in other areas where meltwater was impounded by glacial ice advancing up the regional gradient, in order to understand the complex interaction between depositional processes, ice‐marginal position, and supply of meltwater and sediment in the lake basin. In particular, this model could be applied to decipher the genetic origin of diamicts previously interpreted to record strictly subglacial deposition or multiple re‐advances.
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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 | 0.000 | 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 | 0.001 | 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".