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Porcellanite in Alberta : a pyrometamorphic pre-contact toolstone

Description

Porcellanite is a pyrometamorphic rock that forms when naturally ignited coal seams fuse fine-grained sedimentary rocks. This can produce a uniform material suitable for making stone tools. This... More ≫

Description

Porcellanite is a pyrometamorphic rock that forms when naturally ignited coal seams fuse fine-grained sedimentary rocks. This can produce a uniform material suitable for making stone tools. This paper presents photographs and geochemical analyses of Montana and North Dakota porcellanites in comparison to high quality pyrometamorphic rocks, and Alberta materials of similar origin or appearance. Results of portable X-ray fluorescence, Raman spectroscopy, and thin section analyses are combined with micro/macroscopic traits to aid identification.

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Glacier Pass Concretions : a pre-contact toolstone from an alpine quarry complex in Alberta’s Rocky Mountains

Description

This article summarizes geochemical and mineralogical analyses of the material called Glacier Pass Concretions including portable X-ray fluorescence, thin sections, and hyperspectral imaging.... More ≫

Description

This article summarizes geochemical and mineralogical analyses of the material called Glacier Pass Concretions including portable X-ray fluorescence, thin sections, and hyperspectral imaging. Results indicate that pre-contact toolmakers were aware of internal inconsistencies in concretions and targeted specific high silica bands that produced a better quality, predictable substrate for tools. The article presents photographic libraries to aid identification and summarize an archaeometry-based reconstruction of pre-contact cognitive approaches to a raw material seasonally exploited in an alpine area for several thousand years.

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