|
Sorting describes the distribution of grain size of sediments, either in unconsolidated deposits or in sedimentary rocks. ''Very poorly sorted'' indicates that the sediment sizes are mixed (large variance); whereas ''well sorted'' indicates that the sediment sizes are similar (low variance). The terms describing sorting in sediments - very poorly sorted, poorly sorted, moderately sorted, well sorted, very well sorted - have technical definitions, and semi-quantitatively describe the amount of variance seen in particle sizes. In the field, sedimentologists use graphical charts to accurately describe the sorting of a sediment using one of these words.〔Tucker, M.E., 1996, ''Sedimentary rocks in the field'', John Wiley & Sons, Chichester, 153 p.〕 The degree of sorting may also indicate the energy, rate, and/or duration of deposition, as well as the transport process (river, debris flow, wind, glacier, etc.) responsible for laying down the sediment. Sorting of sediments can also be affected by reworking of the material after deposition, for instance, by winnowing.〔Compton, R. R., 1962, ''Manual of field geology'', John Wiley & Sons, 378 p.〕 Well sorted rocks are generally porous, while poorly sorted rocks have low porosity. ==See also== *Grain size *Graded bedding *Rounding *Porosity *Soil texture *Sediment transport 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sorting (sediment)」の詳細全文を読む スポンサード リンク
|