Siltstone
 | This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. (September 2013) |
| Sedimentary rock | |
 Siltstone |
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.
Description
Siltstone is a clastic sedimentary rock. As its name implies, it is primarily composed (greater than 2/3) of silt sized particles, defined as grains 2–62 µm or 4 to 8 on the Krumbein phi (φ) scale. Siltstones differ significantly from sandstones due to their smaller pores and higher propensity for containing a significant clay fraction. Although often mistaken as a shale, siltstone lacks the fissility and laminations which are typical of shale. Siltstones may contain concretions. Unless the siltstone is fairly shaly, stratification is likely to be obscure and it tends to weather at oblique angles unrelated to bedding. Mudstone or shale are rocks that contain mud, which is material that has a range of silt and clay. Siltstone is differentiated by having a majority silt, not clay.
References
- Folk, R.L., 1965, Petrology of sedimentary rocks PDF version. Austin: Hemphill’s Bookstore. 2nd ed. 1981, ISBN 0-914696-14-9
- Williams, Howel, Francis J. Turner and Charles M. Gilbert, 1954, Petrography, W. H. Freeman
 | This article related to petrology is a stub. You can help Wikipedia by expanding it. |