Bibliographic record
Abstract
In 2013, the Ontario Geological Survey (OGS) initiated a 3D sediment mapping project encompassing the Niagara Peninsula. As with other sediment mapping projects, the goals are to reconstruct the Quaternary history of the area, build a 3D model of Quaternary deposits that form regional-scale aquifers and aquitards, and to define the internal characteristics of each sediment package. This study represents a multi-agency collaborative effort: a regional ground gravity survey (6828 stations covering 3920 km2) and sediment logging of hand auger cores, natural sediment exposures, and 95 continuously cored boreholes have been completed by the OGS; the Geological Survey of Canada has completed shallow seismic reflection surveys (48.1 km) and downhole geophysical logging (14 wells); and 28 monitoring wells have been installed and sampled by conservation authority and municipal partners. This presentation will focus on the results of the 2014-2016 OGS drilling program. The bedrock surface is characterised by southward-dipping strata forming 2 prominent escarpments. Ordovician shale lies below the Niagara Escarpment, Silurian dolostone, shale and gypsum between escarpments and Devonian limestone and cherty limestone above the Onondaga Escarpment. The surface is incised by buried and partially buried bedrock valleys that range from broad and shallow to narrow and deep. Drift thickness is largely controlled by bedrock topography; the thickest sediments are found within the bedrock valleys while the thinnest sediments are found at the escarpments. Drumlins, moraines, deltas and fans form locally thicker sediment accumulations. In the western part of the area there is a thick older drift package of diamicton, glaciolacustrine silt and clay and sand to gravelly sand that can be correlated with the main Late Wisconsin Catfish Creek Till aquitard, late glacial Port Stanley Till aquitard, Grand River outwash aquifer and Wentworth Till aquitard from adjacent 3D sediment mapping areas. The central and eastern portions of the study area are dominated by younger sediments. Coarse-textured ice-contact stratified drift, glaciofluvial sand and gravel and glaciolacustrine sand that forms the Whittlesey aquifer was deposited during and after ice retreat. Thick glaciolacustrine silt and clay was then deposited in a series of proglacial lakes that ponded against the retreating ice front. In the northern and eastern portions of the area these fine-textured glaciolacustrine deposits are separated into lower and upper Whittlesey aquitards by a 'sandwich' of sandy aquifers and muddy Halton Till, diamicton and glaciolacustrine sediments (Halton aquitard) deposited during the late glacial ice advance out of the Lake Ontario basin. The uppermost unit is typically a thin aquifer composed of post-glacial to modern shoreline, aeolian and river sediments. This high-resolution stratigraphy forms the framework for interpreting monitoring well data collected by conservation authorities and municipalities. The results of the extensive drilling program mean that the physical properties of aquifer and aquitard sediments can now be defined across the region. This information, as well as seismic velocities obtained by downhole geophysical logging, will allow verification of seismic time sections into depth sections. It is anticipated that combining the results of drilling and geophysics will provide the best possible definition of buried valley geometry and fill; an important objective of the project. The long-term impact of this study will be to provide conservation authority and municipal partners with an improved water resource decision making tool.
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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 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".