A field classification and intensity scale for first-generation cleavages

The chief morphological characteristics and lithological associations of naturally occurring cleavage fabrics are reviewed with the aim of differentiating qualities that represent fabric type from those that represent fabric intensity, and incidental partings from the cleavage fabric itself. This leads to field-based descriptive classifications for types and intensity of rock cleavage which unify diverse previous observations and allow a more formal approach to the description of cleavage in clastic rocks of low to very low metamorphic grade, although all cleavage types are considered. -from Authors