Theory and application of the Day plot (<i>M</i><sub><i>rs</i></sub>/<i>M</i><sub><i>s</i></sub>versus<i>H</i><sub><i>cr</i></sub>/<i>H</i><sub><i>c</i></sub>) 2. Application to data for rocks, sediments, and soils
Why this work is in the frame
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Bibliographic record
Abstract
New theoretical curves relating the hysteresis parameters M rs / M s and H cr / H c for single‐domain (SD), superparamagnetic (SP), pseudo‐single‐domain (PSD), and multidomain (MD) grains and their mixtures are applied to published data for natural materials. The Day plot of M rs / M s versus H cr / H c has been used to crudely classify samples into box‐like SD, PSD, and MD (or sometimes incorrectly, MD + SP) regions with arbitrary boundaries. New type curves for MD, PSD/SD + MD, and SD + SP grains and mixtures permit more subtle and precise modeling. The predicted MD trend and its junction with the PSD trend are observed in two data sets: for magnetite spherules from carbonate rocks and for temperature‐varying hysteresis results spanning the Verwey transition. The latter data are the basis of a suggested new method for pinpointing the PSD‐MD threshold size. Selected data for pottery clays, soils, and paleosols generally follow SD + MD type curves and indicate intermediate‐size PSD magnetite with narrow to broad size distributions. A lake sediment section with known grain‐size progression tracks in the predicted sense along the SD + MD trend. Selected data for glaciomarine and pelagic sediments are also generally compatible with SD + MD trends. Examples of remagnetized carbonate rocks, submarine basaltic glasses, and glassy rims of pillow basalts all follow predicted SP + SD or SP + PSD mixing curves, with a large range in volume fraction of SP grains (0–75%) but a narrow range of SP particle sizes: 10 ± 2 nm. Larger SP grains spanning the range to SD size (25–30 nm) are absent for unknown reasons. Oceanic dolerites, gabbros, and serpentinized peridotites in some cases fall in a novel region of the Day plot, parallel to but below magnetite SD + MD mixing curves.
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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 | 0.004 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.001 | 0.001 |
| 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 it