Bibliographic record
Abstract
The Arctic Ocean played a major role in millennial-scale climate changes during the last glacial period. In this study, I identified the vast sediment discharge from the proto-Mackenzie River to the western Arctic in the period between 14,500 and 13,200 years ago (Bølling-Allerød [BA] period) and discussed the paleoclimatic significance of this remarkable event. The application of ramped pyrolysis (RP) ¹⁴C dating (Rosenheim et al., 2008) was necessary to date western Arctic sediments. Because RP ¹⁴C dates of sedimentary organic matter do not indicate the age of sediments directly, I invented a calibration method of converting RP ¹⁴C data-set to sediment age. During ramped pyrolysis, the carbon of gas generated at higher temperatures showed an older age. Based on this empirical relationship between pyrolysis temperature and ¹⁴C concentration of generated gas, a new calibration method was proposed to determine the age of sediment within 1600 years (average 460 years) for samples deposited in the past 15,000 years. Using this newly-developed technique, I determined the ages of sediments retrieved from the western Arctic. The stratigraphy of western Arctic sediments was revised based on the combination of lithological (color, gran size, sorting, and IRD abundance), mineralogical and geochemical (organic carbon, sulfur, nitrogen and glycerol dialkyl glycerol tetraethers [GDGTs]) properties. A characteristic silt layer was widely observed in the Chukchi Borderland and the Beaufort Sea. The sediment of this layer is rich in kaolinite, fine coal fragments and abundant soil-derived GDGTs, and its provenance is assumed to be inland Canada where the kaolinite and coal-bearing Cretaceous Scholard Formation. RP ¹⁴C dating indicated that the ages of bottom and top of this layer are 14,500 and 13,200 years ago, respectively, corresponding the onset and end of the BA period. I thus conclude that this sediment was delivered from inland Canada via the proto-Mackenzie River during the BA period. Assuming the density of turbid water discharged from the proto-Mackenzie River, I estimated that the total amount of discharged freshwater was 4.3 × 10⁵ ~ 1.3 × 10⁶km³ during the BA period. This corresponds to 5 ~ 14 % of the total discharged water from world ice sheets during the BA period.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.003 |
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; both teacher heads agree on what is shown here.
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".