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GRAIN‐SIZE INDICES, CLASSIFICATION AND ENVIRONMENT
Author(s) -
DOEGLAS D.J.
Publication year - 1968
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1968.tb01101.x
Subject(s) - sorting , geology , subdivision , loess , classification scheme , skewness , scale (ratio) , geomorphology , mineralogy , cartography , statistics , algorithm , archaeology , mathematics , geography , computer science , information retrieval
SUMMARY Indices based on Wentworth phi values of Q 1 , Md and Q 3 are used for textural classification of sediments. Wentworth phi values enable a detailed subdivision. A nomenclature based on the Wentworth phi indices is developed. The indices, and to a smaller degree the names, show sorting and skewness based on integer phi units. The classification scheme gives a continuous scale from gravel to fine clay. The Q 1 MdQ 3 ‐indices can be used for distinction of river, marine and loess deposits. The addition of indices of the 1st and 99th percentile, giving 5‐digit indices, augments the possibilities for a determination of the environment: river deposits can be distinguished from beach and dune sediments and in more detail from shallow marine and coastal deposits. The indices can be handled by data‐processing machines.