Carboniferous–Permian conodonts and the age of the lower Cutler Group in the Bears Ears National Monument and vicinity, Utah, USA
Bibliographic record
Abstract
The Carboniferous–Permian (C–P) Cutler Group in southeastern Utah archives large-scale environmental changes along multiple facies belts, including major sea-level changes and continental aridification that intensified into earliest Permian times. Nevertheless, the stratigraphical position of the C–P boundary within the Cutler Group has been poorly constrained, until now. Here, we report the first biostratigraphically significant conodonts from shallow-water facies of the lower Cutler beds in the vicinity of Valley of the Gods, San Juan County, Utah. Bulk samples were collected from marine carbonate marker beds spanning up to 160 m of section through the middle Rico to Halgaito formations. Productive carbonates yielding diagnostic conodont elements included the informal marker beds: the McKim limestone and the ‘A’ limestone, representing a variety of shallow-water facies. C–P conodonts included Ellisonia conflexa, Hindeodus sp. and Adetognathus spp. We show that the first appearance of Adetognathus sp. B (Henderson), a species known from the C-P interval (latest Gzhelian – early Asselian) of the Canadian Arctic and east-central British Columbia, places the local base of the Permian at or above the ‘A’ limestone in southern San Juan County. The new records reinforce previous age assignments for the Rico–Halgaito transition beds established on the basis of land vertebrate faunachrons (LVFs) and offer a rare datum for correlating marine and terrestrial C–P faunal assemblages in western Pangaea.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".