Late Eifelian-Early Givetian (Middle Devonian) Brachiopod Paleobiogeography of Eastern and Central North America
Bibliographic record
Abstract
A distinct brachiopod fauna, composed of a mixture of Cordilleran Old World Realm (OWR) endemic genera, cosmopolitan and formerly endemic genera of the Appohimchi Subprovince of the Eastern Americas Realm (EAR), spread across central and eastern North America duringthe late Eifelian (upper part kockelianus Zone). The breakdown of North American Devonian brachiopod provincialism in the late Eifelian-earliest Givetian, as evidenced by mixing of EAR and OWR faunas in the US Midcontinent Devonian carbonate platforms (Iowa and Michigan basins) and Appalachian and Moose River basins, was a direct consequence of widespread transgression of the North American craton at this time. This late Eifelian sea level rise resulted in profound expansion of cratonic seaways that provided avenues for migrations of elements of formerly isolated North American brachiopod faunas. Rocks deposited during this transgression can be correlated in most successions in North America, which corresponds to the sea level rise of Devonian eustatic Transgressive-Regressive (T-R) cycle 1 e . OWR migrants found in U. S. midcontinent and eastern U. S. faunas include Variatrypa ( V .) arctica, Spinatrypa borealis, Spinatrypina, Carinatrypa, Warrenella, W . ( Warrenellina ), Gypidula, Kayserella americana , shallow water species of Emanuella ( E. sublineata, E. meristoides ), Subrensselandia , and possibly Stringocephalus . Some of these, as well as the OWR Independatrypa occur with coeval faunas in the Moose River Basin of eastern Canada. Elements of this paleobiogeo-graphically mixed fauna are now known to occur in coeval deposits of: the Murray Island Formation in the Moose River Basin in Ontario; the Bakoven (upper part), Stony Hollow, and Hurley members of the Union Springs Formation in eastern New York; the Delaware Limestone of Ohio; the Rogers City Limestone of Michigan; the Lake Church Formation of eastern Wisconsin; the Spillville and Otis formations in northern and eastern Iowa; and the Elm Point Formation of southern Manitoba.
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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".