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TitreLate Paleozoic thermochronology of northern Yukon: implications for Phanerozoic basin evolution in northern Canada
AuteurLane, L S; Issler, D R; O'Sullivan, P B
SourceCanadian Society of Petroleum Geologists, Canadian Society of Exploration Geophysicists, Joint Annual Meeting, Abstracts 2015, 2015 p. 1-2
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20140376
ÉditeurCanadian Society of Petroleum Geologists
RéunionGeoconvention 2015; Calgary; CA; mai 4-8, 2015
Documentpublication en série
Mediaen ligne; numérique
SNRC106; 107; 116; 117
Lat/Long OENS-142.0000 -128.0000 70.0000 66.0000
Sujetsanalyses thermiques; antecedents thermiques; hydrocarbures; production d'hydrocarbure; géochronologie; combustibles fossiles; Paléozoïque; Carbonifère
ProgrammeBassin de Sverdrup de l'ouest de l'Arctique, GEM2 : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Apatite fission track (AFT) thermochronological analysis of stratigraphic successions across northern Yukon yields a predominance of latest Cretaceous to Paleogene thermally reset AFT ages related to uplift and cooling in the northern foreland of the Cordilleran Orogen. One small window within the southern Richardson Mountains preserves older AFT ages, ca. 200 Ma, related to pre-Cretaceous thermal resetting followed by partial annealing of fission tracks. In this local area, latest Cretaceous-Paleogene burial and heating were insufficient to completely anneal older tracks. The preserved age and track length data provide important insights into the area¿s Paleozoic time-temperature evolution. Similar ca. 200 Ma cooling ages were recovered from samples in the southern Mackenzie Delta area. Thus, any insights into the regional Paleozoic thermal evolution are applicable beyond the Cordilleran foreland area.
AFT age and track length data, together with U, Th, Pb and major element chemistry, were collected from a Late Devonian sandstone (Frasnian, ca. 372-382 Ma) where the apatite grains belong to at least three statistical AFT populations with different thermal annealing kinetics. We have used multi-kinetic thermal modelling in tandem with local vitrinite reflectance data and constrained by the geological history (based on the exposed stratigraphic relationships). In order to reproduce the AFT results together with the local vitrinite data (Ro = 1.38) and the known geological setting, the sample area had to undergo rapid burial and heating in Early Carboniferous time, followed by exhumation, Cretaceous reburial and finally latest Cretaceous-Paleogene exhumation/cooling. At the Richardson Mountains locality, the young thermal peak was less than 100°C. However, elsewhere in the region, the Paleozoic thermal event can be shown to be less intense, and the younger thermal event more intense.
The Carboniferous thermal event is interpreted as a consequence of Ellesmerian foredeep sedimentation, whereas the latest Cretaceous-Paleogene event reflects Cordilleran deformation. Characterization of two substantial thermal events in the northern Cordillera, together with the correlation of the older event into the adjacent lower Mackenzie Valley, significantly modifies our understanding of the hydrocarbon maturation and expulsion history of basins in this area. Specifically, the late Paleozoic Ellesmerian thermal event may have been sufficient to induce early hydrocarbon generation in Paleozoic source rock successions.
Résumé(Résumé en langage clair et simple, non publié)
Le présent document est un résumé d'une présentation à l'industrie pétrolière canadienne dans le cadre de la conférence annuelle de la Canadian Society of Petroleum Geologists. Il présente une synthèse des nouvelles données sur l'histoire temps-température des bassins sédimentaires pétrolifères dans le nord du Yukon et dans le corridor adjacent du Bas-Mackenzie. Le secteur privé utilise cette information pour modéliser l'âge de la formation ou de la migration du pétrole ou du gaz dans le bassin. Il s'agit d'une variable essentielle pour l'évaluation de la richesse des ressources de pétrole dans un bassin donné.