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Bonnet Plume Basin

| Liard Basin | Kandik Basin | Bonnet Plume Basin | Old Crow Basin | Whitehorse Trough | Peel Plateau and Plain | Eagle Plain Basin | Beaufort-Mackenzie Basin |

View looking south up the Bonnet Plume River with the Bonnet Plume Formation cropping out on the left.

 

 

 

 

 

 

 



The Bonnet Plume Basin is a physiographic and structural depression near the eastern margin of the Frontal Belt of the Cordilleran Orogen in northeastern Yukon. It formed in early Late Cretaceous time by down-dropping Paleozoic strata along regional faults, and contains up to 7,500 m of clastic and carbonate sediments ranging from Precambrian to Tertiary in age. The oldest strata are Precambrian metasediments of the Wernecke Supergroup. This is overlain unconformably by a thick Paleozoic succession of marine limestone and mudstone, including Illtyd, Slats Creek, Taiga, Rabbit Kettle, Bouvette, Canol, Imperial and Road River formations). The Bonnet Plume Formation unconformably overlies the Paleozoic sediments, and is informally subdivided into the lower Bonnet Plume Formation and the upper Bonnet Plume Formation. The lower Bonnet Plume Formation (Middle to Late Albian) is up to 1500 m thick, and consists of interbedded conglomerate, sandstone, mudstone and bituminous coal deposited in a marginal marine to fluvial environment. The upper Bonnet Plume Formation (Maastrichtian to Paleocene) is up to 400 m thick, and consists of fluvial sandstone, mudstone and lignite. The lower Bonnet Plume coals were deposited in fan-marginal and lowland moor settings, whereas upper Bonnet Plume Formation coals were deposited in a lowland moor environment. Only the Road River Formation (Cambrian-Devonian) and Bonnet Plume Formation (Cretaceous-Tertiary) crop out in the Bonnet Plume Basin. Based on Rock-Eval 6 programmed pyrolysis and combustion the petroleum source rock potential of the Bonnet Plume basin is as follows: the Road River Formation (Cambrian-Devonian) has no source rock potential; and the Bonnet Plume Formation (Cretaceous-Tertiary) has gas and perhaps oil potential. Potential oil generation in the Bonnet Plume Formation is attributed to the occurrence of liptinite-bearing coal and previously unrecognized siliceous oil shale. A hydrocarbon-rich tar associated with a naturally burning coal seam also occurs in the Bonnet Plume Formation.