Quartzose sands in the Lower to Middle Devonian strata of southwestern Ontario: geographic distribution and characterization in drill cuttings and geophysical logs
Bibliographic record
Abstract
Southern Ontario is underlain by up to 1425 metres of Paleozoic sedimentary rocks unconformably overlying a Precambrian basement complex of metamorphic and igneous rocks. Four distinct quartzose sandstone units occur within the Middle to Lower Devonian succession: the Columbus sand lithofacies of the Lucas Formation, the Sylvania Formation, the Springvale Member of the Bois Blanc Formation, and the Oriskany Formation. All of the sands form continuous to discontinuous beds and lenses within thick accumulations of regional limestones and dolostones. Locally, these sands are significant hosts of groundwater, oil, and/or gas due to their enhanced porosity relative to the confining carbonates. Information from petroleum wells drilled since the last time these sands were mapped (Bailey and Cochrane, 1985), combined with a comprehensive update of Ontario's petroleum well database, have been used to re-examine the distribution and characterization of these sands. In this study, over 1300 wells containing Devonian-aged strata were examined using binocular microscopy of drill cuttings, geophysical well log analysis, and Geographic Information System (GIS) queries of the Ontario Petroleum Data System (OPDS) petroleum well database. Geographic extents of all four sands have been updated, with sands identified in areas not previously documented. In other cases, stratigraphic assignments were corrected. Petrographic characteristics of the sands, as viewed in cuttings samples, have been documented. Over 800 formation/member top picks have been added or edited, and over 200 picks were identified as erroneous and have been deleted from the petroleum well database. The revised data has been incorporated into an ongoing and broader project to construct a 3D model of the geology and hydrogeology of the Paleozoic bedrock of southern Ontario.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".