Modified Folk Sandstone Classification

Hadi Amin-Rasouli

Earth Sciences Department of University of Kurdistan, Sanandaj, Iran

DOI: https://doi.org/10.17656/jzs.10483

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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