Paleointensity confirms cm-scale sedimentation rates and suggests intervals with non-uniform deposition on the Lomonosov Ridge, central Arctic Ocean
Bibliographic record
Abstract
Chronologies of Arctic Ocean Plio-Pleistocene sediments have been mainly based on paleomagnetic reversal stratigraphy due to low microfossil-content that precludes biostratigraphic dating methods and establishment of an oxygen isotope stratigraphy. Paleomagnetic reversal records primarily from Canadian Basin sediment cores, but also from other Arctic Ocean cores, were initially interpreted as polarity reversals (chron/sub-chron) because paleomagnetic excursions have not until recently been accepted as expressions of genuine geomagnetic features. A Geomagnetic Excursion Time Scale (GETS) has not yet been established and, therefore, the use of excursions as a dating tool is largely dependent on external time control. A number of cores from different regions of the Arctic Ocean have recently been dated interpreting short polarity reversal intervals as geomagnetic excursions. Some of these data reveal narrow intervals with complex patterns of short normal/reversed zones and also absence of excursions at 'expected' depths. Although these observations may be attributed to the short duration of geomagnetic excursions, intermittent bioturbation (?) or other erasing processes, they clearly demonstrate the need for an independent dating control confirming uniformity of accumulation. Paleointensity-records could convey reliable data for relatively high-resolution dating that may disclose variations in rate and uniformity of sedimentation. We present paleointensity records from cores from the Lomonosov Ridge with cm-scale sedimentation rates that carry records of inferred excursions. One of the cores has been dated correlating MnO enriched brown colored layers with interglacial cycles, biostratigraphic marker horizons and excursions (Jakobsson et al, 20001). The absence of excursions in the upper parts of the cores remains unaccounted for. Paleointensity records are correlated with SINT-800, revealing a good correspondence back to ca 250 ka. Below this level correlation becomes blurred. Depth-age plots show two linear segments (similar slopes) separated by a short break, suggesting a temporary change in sedimentation rate (hiatus?). The break corresponds with anomalous variations in the compositional S-0.3T-parameter. 1Jakobsson M., {\o}vlie R., An-Hanbali H., Arnold E., Backman J. and Mörth M., 2000. Manganese and color cycles in Arctic Ocean sediments constrain Pleistocene chronology. Geology, 28, 23-26.
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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 | 0.001 |
| 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".