Explained and Unexplained Spatial and Temporal Variability in Rates of Marine Sediment Accumulation Along the Northeast Margin of the Laurentide Ice Sheet ≤ 14 Ka
Bibliographic record
Abstract
Abstract Changes in sediment accumulation rate (SAR, cm/ky) for fifteen AMS 14C dated late Quaternary sites from along the NE margin of Canada (between 66° and 54° N) are examined. These 15 cores cover the last deglacial cycle of sediment input from the decaying Laurentide Ice Sheet, and subsequent postglacial marine sedimentation on these arctic and subarctic shelves and basins. It is shown that the spatial and temporal variability of the 15 SAR time series do not simply parallel the known glacial chronology. Deglaciation of the shelves initially occurred after Heinrich event 1 (H-1, ≤ 14.5 ka; all dates are in 14C yr). Subsequently, there were major ice advances during the Younger Dryas (YD/H-0, 10-11 ka) and the Noble Inlet glacial events (8.6 ka), with final collapse of the ice sheet ca. 8.0 ka. A total of 73 radiocarbon dates were used, which led to 58 SAR estimates. The median SAR is 69 cm/ky; however, the distribution is strongly positively skewed because of short-lived intervals of very high SAR (∼ 5000 cm/ky, ca. 5000 kg m-2 ky-1). On the Labrador Shelf, high SAR are associated with ice retreat from the Noble Inlet maximum (< 8.6 ka), whereas on the SE Baffin Shelf there is little response in the sediment system to this event. Conversely, during the Younger Dryas/Heinrich-0 (YD/H-0) event, high SARs occur on the SE Baffin Shelf, but along the Labrador Shelf the interval 10-11 ka is marked by modest SARS. Both the 11-10 and 8.6-8 ka rapid sediment accumulation events are marked by considerable increases in the detrital carbonate content, hence bear similarities to the major Heinrich events in the NW Labrador Sea. These unexpected spatial and temporal differences in sediment deposition probably reflect changes in sediment transport trajectories associated with differences in ice (glacial or sea-ice) extent, and atmospheric/oceanic circulations.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.007 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".