Virtual Museum ID: 19-DMA18-003

Specimen Summary

Porphyritic andesite

Locality description: Borrow pit on the east side of Highway 16 just past the bridge over Boulder Creek, approximately 10.8 km north of Moricetown
Structure: Outcrop on the west side of the road shows a contact between thin bedded dark grey tuffs and massive porphyritic andesite flows. The contact dips moderately to the north suggesting the beds here have been tilted in that direction.
Geological Environment: The rocks exposed at this locality and elsewhere in the Rocher Deboule Range were deposited as lava flows and air fall tuffs during the formation of a large late Cretaceous volcanic center.
Age constraints: A sample of porphyritic andesite collected from outcrop on the west side of the road yielded an Ar-Ar isotopic age of 83ma (needs reference)
Notes on stratigraphic assignment: Porphyritic andesite similar to that exposed at this locality and forms a prominent unit within the Rocher Deboule Range. It was originally mapped by Sutherland-Brown as the Brian Boru Formation and was believed to be early Cretaceous. The porphyritic andesite flows are now believed to be late Creataceous and correlative with the Kasalka Group. Elsewhere in the region the Kasalka Group sits unconformably on older early Cretaceous Skeena Group sedimentary rocks (e.g. Sutherland Browns' Red Rose formation in the Rocher Deboule Range) and the Rocky Ridge volcanics.

Specimen Data


The information listed below relates to the current holding location or collection that the sample is from, and whether the item is viewable at that location or is part of a private collection. Coordinates are given as guides, and we remind you that collecting specimens from these locations is not allowed. Caution is advised visiting such sites and Below BC assumes no responsibility for any injuries or trespassing charges that may occur as a result of the viewer entering these sites.

Collection Details

Original Collection:

Smithers Exploration Group (SEG)

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Location Information

Sample Origin:

Seaton, B.C.

Specific Site:

Boulder Creek

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09 (NAD 83)

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Advanced Geological Information


The following section provides geological data relating to the specimen or the site it was collected from, when available. Information has been obtained from various sources including private and government datasets but may not be up to date. Any geological time periods or ages listed often relate to the primary geology of the area, and may not be the actual date of an event such as mineral formation.

Geological Formation:

Kasalka Group

Geological Period:

Late Cretaceous

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Additional Images