An exhumed fine‐grained meandering channel in the lower Permian Clear Fork Formation, north‐central Texas
Bibliographic record
Abstract
Ancient fine-grained meandering channels are under-represented in the literature and their formative processes are rarely explored. The Montgomery Ranch 3 site of the Clear Fork Formation of Texas contains an exhumed fine-grained point bar that migrated for at least 50 m within a channel 2 m deep and 36 m wide. The point bar comprises thick inclined layers of unstratified mudstone intercalated with thin layers of fine-grained, ripple cross-laminated sandstone, with dips averaging nearly 16o. Rill casts and swept ripples on the sandstone surfaces indicate declining water levels. Petrographic analysis of the mudstone shows silt and clay laid down from suspension, but sand-sized mud aggregates transported as bedload (present at other sites in the formation) were not observed. The sandstone beds are attributed to lateral accretion on the point bar during periods of sustained flow, whereas the mudstone beds are attributed to oblique accretion as fine sediment draped the bar during waning and low-flow periods. Sandstone and mudstone units are composite units from numerous flow events and their alternation may reflect secular variation in flood frequency and intensity. In an associated abandoned-channel fill, weakly laminated mudstone with desiccation cracks contains leaves and seeds of Evolsonia texana, marattialean foliage and Taeniopteris sp., with root traces penetrating the leaves. Some taxa preferred high water tables and humid conditions, whereas others were dryland colonisers. This apparent discrepancy may reflect the persistence of wetter channel reaches within an otherwise dry setting. Despite the scarcity of preserved plant fossils, vegetation was probably sufficiently widespread to promote bank strength and local sediment accumulation.
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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".