Bottoms up: developing a new bedrock surface for the Niagara Peninsula
Bibliographic record
Abstract
The Niagara Peninsula three-dimensional (3-D) sediment mapping project was initiated in 2013 with the primary goal of constructing a model of regional-scale Quaternary deposits that form both regional and local aquifers and aquitards between Port Dover in the southwest, the Regional Municipality of Waterloo in the northwest and the Niagara River in the east. To date, the primary focus of the project has been on data acquisition. Five shallow, high-resolution seismic reflection lines, ranging from 4.5 to 21.5 km in length, were acquired by the Geological Survey of Canada's (GSC) Near Surface Geophysics Section to determine whether multiple thalwegs exist within the buried Erigan channel, to delineate the lateral extent and geometry of gravel beds observed during drilling and to provide insight into late-glacial moraine systems. Downhole geophysical logging was conducted in monitoring wells to investigate chemical and physical properties of the sediments, and to verify the conversion of seismic reflection time sections to depths.. A 6828 station ground gravity survey was conducted along selected roads and highways at a nominal spacing of 100 m. The calculated gravity residuals were used to identify buried-bedrock valleys and guide subsequent drilling. The survey was effective in identifying deeply incised valleys, such as St. Davids and the northern end of the Erigan, but less definitive where valleys broaden and the deep regional and shallow residual components of the gravity are not as easily separated. A total of 99 continuously cored boreholes with a combined length of 3192 m, 29 of which have been converted into monitoring wells, have been drilled for this project. The borehole data is augmented by 130 exposures, soil probe and hand-auger cores and extensive legacy datasets (water well records, oil and gas records, geotechnical records, published geological reports and archived field notes). A key first step in the 3-D modelling process is to generate a high-quality bedrock topographic surface that forms the foundation layer for the overlying sediment model. The surface is interpolated using Datamine Studio software after manually digitizing 3-D points identifying the top of rock onto the new and legacy borehole traces. Additional points were digitized adjacent to, or below, the borehole traces in order to refine the geometry of the surface and reduce potential effects of clustered data points. By modelling the gravity results using representative density values for the Quaternary and bedrock layers, and integrating with interpretations from seismic studies in the area, it is possible to further constrain the shape of the bedrock surface. The resulting surface shows southward-dipping bedrock separated by the prominent features of the Niagara and Onondaga escarpments. Deep and narrow re-entrant valleys bisect the resistant escarpments, becoming wider where they cross softer formations.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".