Linking ocean and continental records of paleoclimate: determining accord and discord in the records
Bibliographic record
Abstract
Climate forcing at Milankovitch and sub-Milankovitch frequencies are evaluated by linking climate proxy data from terrestrial and ocean records at two scales of temporal resolution: (1) relatively coarse resolution over the last 500 ka, and (2) higher resolution over the last 200 ka. We determine that climate proxy data from Hole 810C represent regional atmospheric and oceanic processes by comparison to core V21-146, both from the northwest Pacific Ocean. We then compare records that represent regional deposition from China and the western Pacific Ocean to focus on determining Milankovitch-type periodicities. Grain-size and magnetic susceptibility data from Hole 810C and Baoji, China are contrasted using a time-sensitive wavelet analysis. The analyses indicate a general correspondence to Milankovitch frequencies, although there is no specific frequency that dominates throughout the records. Additionally, the dominant 100 000 year frequency does not occur at the same time in the records. These factors suggest that differences in the physical mechanisms of deposition may influence the preserved apparent periodicities in these environments. Lastly, climate events over the last 200 000 years in marine and terrestrial records are correlated at a high resolution in the depth domain. The last interglacial-glacial boundary is consistently placed at the base of a cold period (C20) in the terrestrial and marine records. However, the cold period in the ocean data (δ18O) is very subdued relative to terrestrial records. Additionally, over the last 200 ka, periods of minimum insolation intensity do not correspond linearly to periods of maximum grain-size and ice volume variations revealed in the loess and ocean records, respectively. However, during the warm interstadials of the last two glaciations, peaks in insolation intensity compare favourably with the times of strongest pedogenic development in the continental records and minimum ice volume in the ocean records.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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 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".