ABSTRACT

The proposed classification is a modification and combination of the ideas of several earlier workers and includes concepts formulated by the writer to make the classification of sandstones more reasonable and practical. In the present scheme a sandstone is either named completely with five-fold modifiers (including parameters of structural, textural, and mineral compositional aspects) or briefly named on the basis of mineral composition of the framework by a quartz pole (including single-grain and mesa-aggregate quartz), a feldspar pole (all feldspars together with granitic rock fragments), and a lithic pole (volcanic, metamorphic, and sedimentary rocks including chert or other micro-aggregate quartz). The sandstones may be grouped into four main divisions for field classification: q artzose sandstone, subquartzose sandstone, feldspathic sandstone, and lithic sandstone; thirteen subdivisions are used in laboratory classification. Quartz content is the first criterion in determining a sandstone name and the ratio of feldspar to rock fragment is the second criterion. Most of the rock names used follow McBride's (1963) proposals. This classification is principally descriptive in nature, but the genetic aspect of a sandstone may be synthesized from the descriptive parameters or factors involved in the classification.