Magnetic fabric and inclination shallowing studies: depositional and post-depositional processes in hematite- and magnetite-bearing rocks
Bibliographic record
Abstract
Magnetic anisotropy-based inclinations corrections of both hematite and magnetite-bearing sedimentary rocks indicate latitudinal variations of inclination shallowing. Rocks formed at mid latitudes suffer from more shallowing than those formed closer to the equator, consistent with the tan Im= f * tan If relationship, where Im is the measured inclination and If is the field inclination during deposition. Shallowing of the paleomagnetic vectors can be expressed in terms of the flattening factor f, a function of the rock’s magnetic fabric and the individual particle anisotropy, the a factor. Estimation of the f factor enables performing simplified inclination corrections. f factors derived from anisotropy-based inclination corrections were combined with f factors derived from corrections that use models of geomagnetic field secular variation for hematite and magnetite bearing rocks. Magnetite data indicate a smaller range of f factors, leading to smaller ranges of inclination shallowing. Using the reported range of f factors enables more precise estimations of inclination corrections. Hematite data, on the other hand, show a broader range of f factors, which makes estimating inclination shallowing and correcting for it more difficult. However, because hematite has magneto-crystalline anisotropy, the value of a doesn’t have much variation, thus requiring a precise measure of the magnetic fabric only. Hematite fabrics were measured for an inclination shallowing study of red beds from the Maritime Provinces of Canada (Shepody Fm), using a high field anisotropy of isothermal remanence technique (hf-AIR). The technique allows to fully saturate hematite’s remanence without the need to demagnetize the samples between the different positions required to measure the anisotropy tensor, eliminating the risk of \nthermo-chemical alteration. The technique makes it possible for typical paleomagnetic laboratories to measure the remanence anisotropy of high coercivity hematite. The precise measurement of the fabric allowed interpreting it as a compactional fabric that was reoriented by strain during folding following a flexural-slip model.
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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 | 0.000 | 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) | 0.000 | 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".