Notice bibliographique
Résumé
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.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».