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TitleLate Paleozoic thermochronology of northern Yukon: implications for Phanerozoic basin evolution in northern Canada
AuthorLane, 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
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20140376
PublisherCanadian Society of Petroleum Geologists
MeetingGeoconvention 2015; Calgary; CA; May 4-8, 2015
Mediaon-line; digital
File formatpdf
NTS106; 107; 116; 117
AreaNorthern Yukon
Lat/Long WENS-142.0000 -128.0000 70.0000 66.0000
Subjectsgeochronology; fossil fuels; thermal analyses; thermal history; hydrocarbons; hydrocarbon generation; Paleozoic; Carboniferous
ProgramWestern Arctic Sverdrup Basin, GEM2: Geo-mapping for Energy and Minerals
AbstractApatite 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.
Summary(Plain Language Summary, not published)
This abstract is for a presentation to Canada's petroleum industry at the annual conference of the Canadian Society of Petroleum Geologists. It summarizes new information about the time-termperature history of petroleum-bearing sedimentary basins in northern Yukon and adjacent lower Mackenzie corridor. The private sector uses such information to model the age of oil or gas formation and migration within the basin. This is a key variable in assessing the petroleum resource endowment in any basin.