The ‘classify’ Module

The classify module contains conversion functions, including conversion of numerical statistics into qualitative classifcation names. These functions are called within the GrainSizeDist class, but can also be used individually by the user.

The ‘folk_sed’ Function

The folk_sed function converts sand, silt, and clay proportions into the appropriate sediment classification scheme of Folk (1954).

folk_sed(20, 20, 60)
folk_sed(2.5, 90.2, 7.3)

• Folk, R.L., 1954, The Distinction between Grain Size and Mineral Composition in Sedimentary-Rock Nomenclature: Journal of Geology, Volume 62, Number 4, DOI: https://doi.org/10.1086/626171.

The ‘folk_sort’, ‘folk_skew’, & ‘folk_kurt’ Functions

The folk_sort, folk_skew, and folk_kurt functions classify sediment sorting, distribution skewness and distribution kurtosis into the appropriate classification schemes of Folk and Ward (1957).

folk_sort(1.35)
folk_skew(0.12)
folk_kurt(0.96)

• Folk, R.L., and Ward, W.C., 1957, Brazos River bar: a study in the significance of grain size parameters: Journal of Sedimentary Petrology, Volume 27, Number 1, DOI: https://doi.org/10.1306/74D70646-2B21-11D7-8648000102C1865D.

The ‘wentworth_gs’ Function

The wentworth_gs function converts grain sizes, in phi units, into the appropriate grain size classification scheme of Wentworth (1922).

wentworth_gs(-1)
wentworth_gs(3.6)

• Wentworth, C.K., 1922, A Scale of Grade and Class Terms for Clastic Sediments: Journal of Geology, Volume 30, Number 5, DOI: https://doi.org/10.1086/622910.