Modified Folk Sandstone Classification

Hadi Amin-Rasouli
Earth Sciences Department of University of Kurdistan, Sanandaj, Iran


Abstract

The Folk’s method of sandstone classification has been very commonly
used by many sedimentologists. However, problems may be encountered
using this method of classification. The problems include the size of
matrix, the components used in the poles of triangular diagram, inability to
classify some sandstone samples and the fact that the description of
sandstone and its position in the diagram do not always match. In the
proposed modified Folk classification, all of these problems have been
resolved, the boundary between grain and matrix size is chosen to be
0.0625 mm, and if the matrix is 10 to 50%, wacke term is preferred.
To use this term, it is enough to add wacke to sandstone name after
omitting the arenite, if it was.

Key Words:

Folk classification,
Modified Folk,
Sandstone, Matrix

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