Stratigraphic and structural framework of the Potsdam Group in eastern Ontario, western Quebec and northern New York State
Bibliographic record
Abstract
The presence of a major unconformity within the Potsdam Group is an important key to unlocking the geological history of this succession throughout its area of distribution in the Ottawa Embayment and Quebec Basin. The beds below the unconformity (Abbey Dawn and Covey Hill/Ausable formations) largely of continental origin up to 600 metres thick, is a complex assortment of red and grey quartzite cobble, quartz pebble and quartzarenite deposits of assumed Neoproterozoic to Early Cambrian age. The Covey Hill/Ausable formations have been further divided into four units of wide distribution beginning with the Jericho member of marginal marine origin, confined to the Quebec Basin bordering the Oka-Beauharnois Arch; succeeded and overlapped to the west by Hannawa Falls, Chippewa Bay and Edwardsville members of aeolian, fluvial and possible lacustrine origin. During and immediately following deposition of these members the beds were locally faulted, folded and subjected to a long period of subaerial erosion. This process was likely triggered by a plate tectonic event in progress during Neoproterozoic to early Early Cambrian time, when the continents were in a state of rifting and break-up, followed by the opening of the Iapetus Ocean. Above the unconformity are the white and grey Nepean and equivalent Cairnside and Keeseville formations up to 110 metres thick composed of quartzarenite and minor quartz pebble conglomerate of Late Cambrian to Early Ordovician age. These formations were deposited on the floor and margins of a seaway that entered the Ottawa Embayment from the east. The highland areas (arches) on all four sides of the embayment provided restricted marine depositional conditions that contributed to the precipitation of minor evaporates, a proliferation of stromatolites and a limited normal marine biota contained within the Nepean sandstone and its stratigraphic equivalents. Post-Potsdam deformation resulted in the rejuvenation of faults and local folding of Potsdam and younger Paleozoic strata throughout the Ottawa Embayment and Quebec Basin, the timing of which was likely associated with Taconian and Acadian orogenesis, and by the much later rifting of the North American continent that occurred with the break-up and separation of the continents in the Jurassic and Cretaceous.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".