A Classification of Common Sandstones

Abstract

ABSTRACT A descriptive classification of sandstones (exclusive of carbonate and volcaniclastic sandstones) based on the composition of framework grains is proposed that can be used equally well in the field and laboratory. The framework grains are grouped into (1) quartz plus chert and quartzite, (2) feldspar, and (3) rock fragments which constitute the end-members of the quartzarenite, arkose, and litharenite clans respectively. The clans are subdivided to make eight major rock types. Graywacke is defined on the basis of both texture and framework composition and is treated as a special rock type instead of as a clan or subclan type. Because the texture of a sandstone is as important an attribute as framework composition, a polynomial system of sandstone nomenclature should be used in which at least grain size and clan name are cited (i.e., muddy coarse arkose).