Ammonoids from the Tully Formation and Harrell Shale in Pennsylvania: Markers of sea-level highstands in the Middle to Late Devonian transition, Appalachian foreland basin, eastern North America
Bibliographic record
Abstract
ABSTRACT Zone-diagnostic Middle to Upper Devonian ammonoids and conodonts occur in a sequence of thin carbonate beds in siliciclastic sections along the Allegheny front and northern fold belt of central Pennsylvania. The lowest, in the upper Tully Formation, and the succeeding four in the Harrell Shale, are southward continuations of marker beds long known in the Tully Limestone and overlying basin, slope, and shelf facies of the Genesee Group of New York State. These pelagic beds are Appalachian Basin signals of transgressive condensed intervals within global high-sea-level episodes and are associated with a worldwide biotic overturn in the tropical marine realm. The Upper Givetian Tully Pharciceras amplexum bed has close lithic and faunal equivalents in the Taghanic biocrisis interval in Morocco and southern Europe. The Lower Frasnian styliolinid upper Genundewa Limestone, with the entry of Manticoceras, and, in the succeeding dark West River Shale, the Bluff Point Bed, with the entry of late Koenenites and early palmatolepid conodonts, are Appalachian highstand signals of the worldwide Timan bioevent transgression recognized in Western Australia, the Russian Platform, southern Europe, Morocco, western Canada, and now Pennsylvania. The widespread occurrences of discrete ammonoid beds, even in the more proximal or shoreward sedimentary settings of the Catskill Delta, reinforce the view that they accumulated under conditions of sequestered sediment supply when transgressions flooded the newly vegetated and deep-root-forested delta flats. As such, they overprinted or interrupted the westward progradation of siliciclastic sediments generated by mountain-building tectophases of the Acadian orogeny. The Lower Frasnian ammonoid Epitornoceras dennisoni n. sp., described herein, from the Crosby Beds in the Harrell Shale at Milesburg, Pennsylvania, is named in honor of John Dennison.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".