Thermokarst and Related Landforms in Western Utopia Planitia, Mars: Implications for Near-Surface Excess Ice
Notice bibliographique
Résumé
Introduction: Using high resolution Mars Orbiter Camera and Thermal Emission Imaging System images, we have identified pits that occur at the junction of polygons (referred to as polygon pits) (fig. 1) in western Utopia Planitia (UP), Mars (241.71° W, 305.27° W and 39.46° N, 57.57° N). We argue that the polygon pits are geomorphologically consistent and possibly have the same origin as thermokarst related landforms on Earth. Terrestrial thermokarst: Thermokarst landforms occur in areas where a disturbance in the thermal regime of ice-rich (excess ice) permafrost induces thaw. This leads to the melting of ground ice, the ponding of water, further melting of ground ice due to the high thermal capacity and conductivity of water, the subsequent collapse of surficial material and the formation of pits and depressions. A widespread contributing factor to thermokarst degradation is the presence of thermal contraction polygons underlain by ice-wedges [1], hence the close spatial association between the two landforms. During the warmer seasons water accumulates at polygon junctions (fig. 2) due to the melting of snow and exposed or near-surface ice-wedges or ground ice. The higher thermal capacity and thermal conductivity of water invariably causes the melting of ground ice and promotes further thermal erosion of ground ice. The loss of water through drainage, evaporation, or sublimation forms a pit at the junction of polygons. Pits and polygons in western UP: Polygon pits (fig. 1) and polygonal terrain (fig. 1) are widespread in western UP. The polygons have trough-to-trough diameters that range between ~50–150m [2]. Polygon pit size ranges between ~14-58m (mean diameter=36 m, n=77) in diameter and their shape varies from circular to slightly elongate. Polygon pit depth varies between 5–36m (mean depth=17.4, n=77). In many instances, the polygon pits exhibit a beaded pattern. Most pits occur at polygon junctions. Interspersed among the polygon pits are larger depressions (~200-3500m in diameter) that occur in isolation or coalescence. Geological interpretation: Depressions similar in morphology to the polygon pits in UP are common in the area surrounding the Tharsis rise. Such features, called pit craters, form when surface material collapses into a sub-surface cavity created by endogenetic processes (e.g. [3], [4]). Due to their origin, pit craters commonly occur within graben systems or near areas that display extensional or volcanic stresses such as fault lines, lava tubes and collapsed magma chambers (e.g. [5], [6]. Wyrick et al. [7] suggest that the polygon pits of UP are the product of processes similar to those of pit crater formation near the Tharsis region. However a geomorphological analysis between the pit craters and the polygon pits reveals several discrepancies.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| 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 | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
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 tête enseignante, 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 ».