Folk's Sandstone (clastic) Classification
Folk's philosophy is that the name of a rock must convey as much information as possible without being a complete description. For this, he proposed five important properties of sandstones to use as defining characteristics. These five properties are: grain size, chemically precipitated cements, textural maturity, miscellaneous transported constituents, and clan designation. Folk's fivefold name must be in the following format:
- (Grain size): (chemically precipitated cements) (textural maturity) (miscellaneous transported constituents) (clan designation)
However, Folk stated that cements and miscellaneous transported constituents are optional categories as they are not always observed. The other three properties should always be mentioned.
The following are examples of rock names using Folk's fivefold name:
- Coarse sandstone: calcitic submature micaceous subarkose
- Fine sandstone: supermature quartzarenite
- Sandy granule conglomerate: calcitic submature calclithite
- Very fine sandstone: chert-cemented submature quartzose phyllarenite
- Clayey very fine sandstone: immature fossiliferous plagioclase arkose
Read more about this topic: Folk Classification
Famous quotes containing the words folk and/or sandstone:
“I think that Richard Nixon will go down in history as a true folk hero, who struck a vital blow to the whole diseased concept of the revered image and gave the American virtue of irreverence and skepticism back to the people.”
—William Burroughs (b. 1914)
“But the lightning which explodes and fashions planets, maker of planets and suns, is in him. On one side elemental order, sandstone and granite, rock-ledges, peat-bog, forest, sea and shore; and on the other part, thought, the spirit which composes and decomposes nature,—here they are, side by side, god and devil, mind and matter, king and conspirator, belt and spasm, riding peacefully together in the eye and brain of every man.”
—Ralph Waldo Emerson (1803–1882)