Geldart classified particles into four groups by the particle size and its characteristics.

吉尔达特根据颗粒大小及其特性将颗粒分为四组。

Small particle size; good mechanical stability.

粒径小；机械稳定性好。

Particle size of deposition change greatly, bad sorting.

沉积物粒径变化较大，分选差。

In clastic sediments particle size is an important factor.

在碎屑沉积物中，颗粒大小是个重要因素。

In clast IC sediments particle size is an important factor.

在碎屑沉积物中，颗粒大小是个重要因素。