--> Abstract: Stratigraphic Architecture of a Distal Basin-Floor Fan System (Upper Kaza Group, Western Canada), by Lori Meyer and Gerald M. Ross; #90039 (2005)

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Stratigraphic Architecture of a Distal Basin-Floor Fan System (Upper Kaza Group, Western Canada)

Lori Meyer1 and Gerald M. Ross2
1 Imperial Oil Resources Limited, Calgary, AB
2 Kupa'a Farm, Kula, HI

The Upper Kaza Group and correlatives in the southern Canadian Cordillera are part of an extensive sand-rich, basin-floor turbidite system formed at the base of the Neoproterozoic continental slope. Periglacial exposures of the Upper Kaza Group at Castle Creek (British Columbia) provide a unique opportunity to characterize the most distal component of the basin-floor fan system.

The Upper Kaza Group, up to 800 metres thick at this locality, has been mapped in detail on high resolution aerial photographs with bed by bed correlations and lateral continuity established by physically walking out surfaces between measured vertical sections in the study area. The resultant stratigraphic panels illustrate changes in local sediment supply and base level as a consequence of proximity to a major feeder channel system. The lower panel is characterized by lobate depositional elements with low relief that change laterally into mudstone-rich facies as is evident both from detailed mapping and associated outcrop gamma ray profiles. Scour and bypass surfaces and consequently, diminished lateral continuity of sandstone-rich lobes characterize the middle panel. Laterally continuous strata and sheet-like depositional elements characterize the upper panel.

This vertical succession is interpreted to record a prograding basin-floor fan with lateral shifts from axis to off-axis deposition. The vertical stratigraphic changes of the Upper Kaza Group at Castle Creek can be placed in the context of modern sand-rich fan systems as seen on 3D seismic profiles and provides a working model for evaluating potential traps and reservoir continuity in an unconfined basin-floor fan setting.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005