Exploring the significance of true substrates in a Pennsylvanian fluvio–estuarine tidal flat
Bibliographic record
Abstract
The Pennsylvanian Tonganoxie Sandstone of Kansas contains examples of true substrates in tidal rhythmites formed in a tidal flat at the fluvio‐estuarine transition of a macrotidal valley. These surfaces are characterized by an impressive preservation of biogenic and physical sedimentary structures, indicative of the coexistence of low-energy tidal currents and freshwater conditions together with brief periods of subaerial exposure. Biogenic activity corresponds to a time of stasis during or immediately after accumulation of ebb-phase clay followed by low tide. Deposition–stasis–deposition (D–S–D) was involved in the formation and preservation of these true substrates, with only a few instances of deposition–stasis–erosion–deposition (D–S–E–D). Crosscutting relationships among biogenic structures and of these with physical sedimentary structures suggest a tidally controlled taphonomic pathway, which indicates that these true substrates represent short-term time-averaged surfaces at the scale of a few hours, rather than snapshots. True substrates preserved in tidal rhythmites are widespread in other late Paleozoic tide-dominated estuarine deposits of the North American Midcontinent. The likelihood and quality of preservation seem to show spatial and temporal trends at various scales that ultimately reflect a complex interplay of abiotic factors (e.g. sedimentary dynamics) and biotic factors (e.g. secular changes in intensity and depth of bioturbation).
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".