GEOSCAN, résultats de la recherche


TitreSeismic imaging of the geological framework and structures related to volcanogenic massive sulfide deposits in the Archean Rouyn-Noranda district, Quebec, Canada
AuteurBellefleur, G; de Kemp, E; Goutier, J; Allard, M; Adam, E
SourceEconomic geology and the bulletin of the Society of Economic Geologists vol. 109, no. 1, 2014 p. 103-119,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100217
ÉditeurSociety of Economic Geologists
Documentpublication en série
Mediapapier; en ligne; numérique
Lat/Long OENS-79.2500 -79.0000 48.4167 48.2500
Sujetsgîtes sulfureux; Archéen; interpretations structurelles; levés de reflexion sismiques; levés géophysiques; interprétations géophysiques; roches volcaniques; lithologie; rhyolites; andésites; altération; trous de mine; établissement de modèles; profils sismiques; filons rocheux; diorites; gabbros; diagraphie géophysique; diagraphie de densité compensée; Formation de Noranda ; Groupe de Blake River ; Pluton de Flavrian ; géophysique; géologie structurale; Précambrien
Illustrationsseismic reflection profiles
ProgrammeAbitibi IGC-3, Initiative géoscientifique ciblée (IGC-3), 2005-2010
ProgrammeDeveloppements methodologie, Initiative géoscientifique ciblée (IGC-4)
ProgrammeÉtude des gîtes d'or, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
Two seismic reflection profiles acquired by Xstrata Canada in the Noranda mining camp were re-processed and interpreted with the objective of providing key information on the geological contacts and structures associated with volcanogenic massive sulfide (VMS) deposits at depth. The Amulet and Ribago seismic profiles run approximately from east to west and cross the volcanic rocks of the Noranda formation which host most of the ore deposits in this camp. The seismic data interpretation relies strongly on a detailed 3D geological model built from an extensive number of exploration boreholes available in this area and is further supported by physical rock property measurements from in-situ borehole logging data. Some reflections observed on the Amulet and Ribago seismic profiles correlate with rhyolite-andesite or silicified andesite-andesite contacts hosting prospective exhalite horizon of the Noranda formation. In particular, the silicified andesite-andesite contact hosting the C-contact is imaged clearly down to a vertical depth of 1100 m along the Ribago profile. The processing sequence that included dip move out (DMO) corrections and poststack migration used for the seismic data re-processing allowed the identification of two diffractions that correlates with known sulfide bodies intersected in boreholes located close to the Ribago profile. One of these diffractions at approximately 1200 m coincides with the main massive sulfide intersection of the sub-economical Ribago orebody. Diorites explain several reflections observed within the Flavrian pluton. Some diorite units also have sufficient contrasting acoustic impedance to produce strong reflections when juxtaposed against volcanic rocks. However, such reflections are not predominant on the Amulet and Ribago profiles, possibly because reflective diorite units are not so significant or have limited lateral continuity in this part of the Noranda formation. The reconciliation of the detailed 3D geological model and 2D seismic data was not necessarily a straightforward task. A significant complication results the inherent limitations of 2D seismic imaging techniques in a complex 3D geologic environment. Nevertheless, results presented in this paper indicate that seismic methods can image prospective contacts and deep-seated massive sulfide mineralization and can be a valuable exploration tool in the Noranda mining camp.