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ARKOSIC SANDSTONE Go on to: #1 | #2 | #3 | #4 Arkosic (feldspathic) arenite 
Detail of this specimen>>> Return to previous
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QFL Composition
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Description
A sandstone with a mixture of quartz and orthoclase feldspar (pink). The sand grains stand out in high relief in this specimen (i.e. there is little matrix) placing this in a sand category.The sand grains here are very large, some even drifting over into the granule size range (2-4 mm) which would technically make this a gravel (conglomerate). We put it here since most of the grains fall into the sand category. |
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Tectonic Association
Arkoses with abundant feldspar such as this come from the weathering of a sourceland rich in alkali granite. The absence of virtually any other grains other than quartz and feldspar indicate the immediate source of this rock was not a mixed sourceland.
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Formation & Environments
A sandstone this clean (i.e. without matrix) indicates a source where chemical weathering was not extreme. The course grain size and relatively good sorting of this sediment implies water transportation, probably in a braided river system.
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