STRUCTURAL STATE OF K-FELDSPAR IN THE FELSIC VOLCANIC ROCKS AND RING PLUTON GRANITES OF THE BUTLER HILL CALDERA, ST. FRANCOIS MOUNTAINS, SOUTHEASTERN MISSOURI
Bibliographic record
Abstract
The K-feldspar in all major rock units exposed in the Middle Proterozoic Butler Hill Caldera, St. Francois Mountains, south-eastern Missouri, shows a high, but not maximum, degree of structural order. The structural state parameter Z for phenocryst material from the felsic volcanic rock units averages 0.89, with a standard deviation of 0.06 (Z would be 1 in fully ordered microcline). K-feldspar extracted from the matrix of these same samples yields an average Z value of 0.86, with a standard deviation of 0.07. The Z parameter for the K-feldspar in the ring pluton granites averages 0.87, with a standard deviation of 0.06. The structural state of the K-feldspar in these ring pluton granites is virtually identical to that reported by our group for the Butler Hill – Breadtray Granite, the subvolcanic granite massif exposed in the center of the Butler Hill Caldera. There is no statistically significant variation of K-feldspar structural state with inferred structural elevation, present topographic elevation, or proximity to the Simms Mountain Fault. We interpret the homogeneity of the K-feldspar structural state throughout the Butler Hill Caldera complex, and especially the unexpectedly high degree of structural order in the volcanic K-feldspar, as evidence for a pervasive alteration event, which re-ordered the K-feldspar throughout the entire volcanic–plutonic complex. The most likely cause of the homogenization of the K-feldspar structural state is the late-stage alkaline magmatism inferred to have occurred throughout the St. Francois Mountains at approximately 1.36 Ga.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| 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 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".