Classification of sedimentary rocks holds challenges that igneous and metamorphic classifications do not:
Useful classifications of sedimentary rocks require understanding and using Ternary Diagrams. Go here (Classification Schemes) to learn more on how to describe and classify sedimentary rocks.
- First, unlike igneous rocks where appearance easily leads to classification and interpretation, superficial appearance in sedimentary rocks does not always work well. Two rocks classified the same way may not look all that much alike, and similar looking rocks may not be at all related.
- Second, it is not as easy to identify or estimate the abundance of the components (minerals and rock fragments) that compose the rock, and in anything more than a superficial classification composition this is crucial.
- Finally, sedimentary rocks come in such a large variety, and form from such a wide diversity of processes, that it is difficult to classify or say anything simply or comprehensively about them. The exceptions to the "rules" are numerous.
Contributed by Lynn Fichter
Wednesday, October 08, 2014