Magnetization carriers of grey to red deep-water limestones in the GSSP of the Givetian–Frasnian boundary (Puech de la Suque, France): signals influenced by moderate diagenetic overprinting
Bibliographic record
Abstract
Abstract Limestones at the Puech de la Suque Global Boundary Stratotype Section and Point (GSSP) of the Givetian–Frasnian boundary show a drastic change towards much higher magnetic susceptibility values in the Givetian rocks. Different rock magnetic parameters indicate that ferromagnetic minerals are the main controlling factor. The ferromagnetic fraction is composed of low- (magnetite-type) and high-coercivity (hematite and goethite) phases. Confirmed by the spectral reflectance, high coercivity minerals are fluctuating along the section with a higher abundance in the basal Frasnian. These phases may be of secondary origin and produced during burial stage. The magnetite-type phase contains two different grain-size populations. The identified that Stable Single-domain/Superparamagnetic (SSD/SP) particles are of diagenetic origin and their amount decreases slightly upwards. A second group of magnetite grains correspond to coarse-grained particles identified using the squareness v. coercive force plot. It is tentatively suggested here that these particles present throughout the section are of primary origin. On the contrary, the paramagnetic minerals underwent a clear diagenetic overprinting and may represent secondary minerals. The presence of a primary ferromagnetic carrier allowed the use of spectral analyses, leading to the detection of spectral peaks at 1.25 and 4 cycles/m, which can be interpreted as the result of 405-kyr and 100-kyr eccentricity forcing, respectively.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.002 | 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".