GEOSCAN, résultats de la recherche

Menu GEOSCAN


TitreUpper crustal investigation of the Gulf of Saint Lawrence region, eastern Canada using ambient noise tomography
AuteurKuponiyi, A P; Kao, H; Van Staal, C; Dosso, S E; Cassidy, J F; Spence, G D
SourceJournal of Geophysical Research, Solid Earth vol. 122, issue 7, 2017 p. 5208-5227, https://doi.org/10.1002/2016jb013865
Année2017
Séries alt.Ressources naturelles Canada, Contribution externe 20170080
ÉditeurAmerican Geophysical Union
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1002/2016jb013865
Mediapapier; en ligne; numérique
Formatspdf
ProvinceRégion extracotière de l'est
Lat/Long OENS -68.0000 -58.0000 56.0000 42.0000
Sujetsondes transversales; ondes R; ondes sismiques; données sismiques; études de la croûte; evolution de la croûte; géophysique
Illustrationslocation maps; geophysical images; graphs; seismic reflection profiles
ProgrammeGas de schiste - sismicité induite, Géoscience de l'environnement
Diffusé2017 07 11
Résumé(disponible en anglais seulement)
We studied the 3-D shear wave velocity (Vs) structure in the region of the Gulf of St. Lawrence and adjacent onshore areas to 20 km depth by inverting Rayleigh-wave dispersion extracted from the vertical components of continuous ambient seismic noise waveforms. The GSL and the adjacent land areas were divided into three broad zones based on their Vs characteristics. In the northwest, the Grenville Province (i.e., the exposed edge of predominantly Middle Proterozoic Laurentian crust) is dominated by high-Vs, except for well-known anorthosite sites, which are characterized by relatively lower Vs. In contrast, the central segment of the GSL region corresponds to a belt with generally low-Vs at upper crustal levels. In the southeastern part of the GSL, prominent low velocities in the uppermost crust are found to coincide with locations of subsidiary basins of the Canadian Maritime Basin, while higher Vs characterize the accreted Appalachian terranes where they are exposed on land. The Grenville Province is wedged out at depth by the Red Indian Line, which is the suture between composite Laurentia and peri-Godwanan Ganderia in the Canadian Appalachians. The geometry and Vs characteristics of the south-easternmost peri-Gondwanan terranes of Avalonia and Meguma, suggest that they may be fully or partially structurally overlying a basement with distinct seismic characteristics, which could be a vestige of the West-African craton that was under-thrust beneath composite Laurentia during the terminal Alleghenian continent-continent collision. In the middle of the GSL, the 3-D geometry of the Canadian Maritimes sedimentary basins overlying the Appalachian terranes shows that the depth to the top of basement is in excess of 8 km.
Résumé(Résumé en langage clair et simple, non publié)
Les formes d'ondes sismiques continues enregistrées dans toutes les stations sismographiques disponibles dans la région du Golfe du Saint-Laurent (GSL) sont analysées en déduire le champ de vitesse tridimensionnelle de l'onde de cisaillement (Vs) des bassins sédimentaires et de la croûte supérieure. Une zone généralement à faible vitesse sépare les structures de haute Vs de la province de Grenville au nord et les terranes des Appalaches du sud-est. Les résultats de cette étude fournissent des contraintes sans précédent sur la géométrie globale des bassins sédimentaires majeurs dans le GSL et les terranes accrétés responsables de la formation de la ceinture de montagne des Appalaches.
GEOSCAN ID301651