An Integrated Approach to Paleo-Ice Stream Determination in Mid Continental Prairies, Saskatchewan, Canada
Notice bibliographique
Résumé
Ice stream research has gained momentum in the last decade due to the increased need to understand ice sheet dynamics and instability and, by extension, the role ice streams have on climate change and sea level rise. Although significant progress has been made recently in understanding the role of ice streams in ice sheet dynamics, much remains to be done for documenting and understanding paleo-ice stream records. This is especially true for terrestrial paleo-ice streams like those that operated in the southwest Laurentide Ice Sheet. In previous studies evidence was shown for at least two large paleo-ice stream systems in southern Saskatchewan and a model was proposed involving major glacial dynamics shifts during the Late Wisconsinan linked to ice streaming in the Prairies. The goal of this research is to further characterize drift provenance and to verify sediment-landform assemblages that are central to the proposed reconstruction. This is done through spatial analysis of sediment and landform characteristics (e.g. compositional data, till fabric, landform identification). Provenance is also investigated using radiometric data and 40Ar/39Ar dating of hornblende grains. All of the data are geo-referenced in GIS to examine the spatial relationships. Results show spatially consistent patterns that fit within the structure of the proposed ice stream model. Ten assemblages were delineated, some showing landform evidence of southwestern and southeastern flow, while others show an older western signature through compositional data. The ice flow dynamics were characterized by a combination of landform evidence and compositional data, where three distinct ice flow phases can be seen. Of these three flow phases, two can be characterized by paleo-ice streams. The older south westward Maskwa system flowed against the regional slope, creating a large area of mega-scale glacial lineations, as well as transverse ridges, and was bound on either side by hummocky terrain. The preservation of the southwest Maskwa system was due to the abrupt shift to the southeastward Buffalo system. The Buffalo system captured the subglacial water from the Maskwa causing its shutdown, which fed the James Lobe until it collapsed. The Buffalo paleo-ice stream was the youngest and least stable of the two systems, as shown in the cross-cutting landform evidence. This approach combines multiple methods of analysis to go beyond the geomorphologic evidence to test the main underlying assumptions of paleo-ice stream landsystem models. This is critical if we are to understand the processes involved in the formation of paleo-ice streams and to reconstruct their evolution. Further characterization of the paleo-ice stream systems in the Prairies is critical to improve our understanding of how large ice sheets, like the Laurentide Ice Sheet, evolved and eventually collapsed.
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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,003 | 0,005 |
| Études des sciences et des technologies | 0,002 | 0,000 |
| Communication savante | 0,002 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,004 | 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 ».