Secondary Mineral Genesis from Chlorite and Serpentine in an Ultramafic Soil Toposequence
Bibliographic record
Abstract
The origin of secondary phyllosilicates in serpentinitic soils of differing moisture regimes is incompletely understood. The objective of this study was to determine the genesis of weathering products in serpentinitic soils along a moisture regime gradient using conventional x‐ray diffraction (XRD) methods and high‐resolution transmission electron microscopy (HRTEM). The samples studied were obtained from an Aquic Argixeroll and a Cumulic Endoaquoll on the Trinity ophiolite, in the Klamath Mountains, California. The soils are from backslope and toeslope landscape positions associated with a 3.2‐ha wetland on a stabilized landslide bench. Chlorite and serpentine are the major primary minerals in the soils. Chlorite is relatively stable and was found in the clay fraction of all horizons studied. Serpentine was observed in all horizons except the Aquic Argixeroll Cr2 horizon. The soil mineral assemblages indicate that chlorite transforms to vermiculite and both randomly and regularly interstratified chlorite/vermiculite by loss of the hydroxide‐interlayer sheet. The vermiculite then alters to a high‐charge smectite that was found only in the lower horizons of the backslope landscape position. Smectite is the predominant secondary mineral in all horizons. Serpentine transformation products could not be directly identified, but the prevalence of a low‐charge smectite in the Cumulic Endoaquoll is interpreted as a precipitate from serpentine dissolution products. Thus, the abundant smectite in these serpentinitic soils is of two origins: (i) a high‐charge phase derived from chlorite transformation that is found in the backslope landscape positions, and (ii) a low‐charge phase neoformed by precipitation of elements released by serpentine weathering.
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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 | 0.000 | 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 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".