A Proposed Diachronic Revision of Late Quaternary Time-Stratigraphic Classification in the Eastern and Northern Great Lakes Area
Bibliographic record
Abstract
A succession of stratigraphic codes (1933, 1961, 1983) has guided attempts to refine classifications and naming of stratigraphic units for Quaternary deposits of the Great Lakes region. The most recent classifications for the late Quaternary of the Lake Michigan lobe (1968) and the eastern Great Lakes (1972) have been widely used, but later work has created the need for revision. An attempt has been made to integrate the two previous classifications following the diachronic system of the 1983 Code of Stratigraphic Nomenclature. A new nomenclature for the higher, more broadly recognized units was presented in 1997. We here present the diachronic nomenclature for finer subdivisions recognized in the eastern and northern Great Lakes. Following the interglacial Sangamon Episode, the three parts of the Wisconsin Episode are further subdivided as follows: the Ontario Subepisode (former Early Wisconsinan) comprises the Greenwood, Willowvale, and Guildwood phases; the Elgin Subepisode (former Middle Wisconsinan) comprises the Port Talbot, Brimley, and Farmdale phases; and the Michigan Subepisode (former Late Wisconsinan) consists of Nissouri, Erie, Port Bruce, Mackinaw, Port Huron, Two Creeks, Onaway, Gribben, Marquette, Abitibi, and Driftwood phases. Succeeding interglacial time to the present is the Hudson Episode.
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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 | 0.008 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.004 |
| Science and technology studies | 0.003 | 0.005 |
| Scholarly communication | 0.005 | 0.004 |
| Open science | 0.003 | 0.001 |
| Research integrity | 0.001 | 0.004 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".