Depositional and circulation changes at the Chukchi margin, Arctic Ocean, during the last two glacial cycles
Bibliographic record
Abstract
The shallow Chukchi-East Siberian margin of the Arctic Ocean was repeatedly impacted by Pleistocene glaciations and related changes in sea level and circulation. The depositional history across the last two Arctic glacial cycles is investigated in sediment core ARC6-C15 from the foot of the Chukchi Rise, an extension of the Chukchi Sea shelf that was impacted by the East Siberian Ice Sheet (ESIS). Our proxy data indicate a large extent of the ESIS, likely blocking the westward sediment transport from the Laurentide Ice Sheet (LIS) during the penultimate glaciation estimated to have occurred within an age span from Marine Isotope Stage (MIS) 4 to 6. The deglacial environments are characterized by enhanced sediment inputs from the East Siberian and Chukchi shelves, while overlying interstadial/interglacial sediments have a signature of the Chukchi Sea and the Beaufort Gyre. During the last glaciation , the ESIS had a smaller impact on the Chukchi margin, and the deglaciation was dominated by the LIS sediment sources. Glacial discharge from the Mackenzie area is identified in the Bølling/Allerød interval, while later deglacial pulses can be tracked to the Canadian Arctic Archipelago. In addition to glacigenic sediment inputs, both deglacial intervals contain Fe Mn micronodules, possibly formed under the influence of meltwater pulses during sea level rise . An increase in the chlorite content that likely marks the flooding of the Bering Strait is identified at the start of the Holocene . A pronounced oxygen and carbon isotope excursion in the early Holocene may indicate hydrographic changes in the Arctic Ocean related to the 8.2 ka meltwater discharge event.
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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) | 0.001 | 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 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".