Sediments and Sedentate - Sand

Page / - last modified by Roelof Zwaan on 2022/01/10 17:00

Sand

last modified by Roelof Zwaan

on 2022/01/10 17:00

Table of Contents

Sand is a granular sedimentary rock. In most european definitions of sand, the grains need to have a diameter from 63 micrometer to 2 millimeter. The grains of this rock are coarser than those of silt and less coarse than those of gravel.

Sub-categories

Within the grainsize of sand there are some subcategories to characterize the types of sand. Following table describes them.

Type	Grainsize
Coarse sand	> 0.63 - ≤ 2.0 mm
Medium coarse sand	> 0.2 - ≤ 0.63 mm
Fine sand	> 0.063 - ≤ 0.2 mm

How to determine the sandsize

There are tools to help determine the fraction size of the sand. Often a sandruler can be used to aid in determining the fraction.

Combinations

Sand with shells

Shell sands consists mainly of shells of marine organisms like brachipods, clams, oysters, etc. Usually found close to or near sea.

Sandy gravel/gravelly sand

This is a combination between gravel and sand. Where the pronoun describes the smaller fraction present.

Sandy limestone

Limestone is often impure. Calcium carbonate may be mixed with siliciclastic material (clay, sand) in all proportions, but calcium carbonate must form the majority. Otherwise, we have calcareous sandstone or marl instead of limestone. The term “marl” is mostly used in the field and often somewhat muddy limestones, even if they contain more calcium carbonate than mud, are called that way. When sand has a large fraction within the mixture one can speak of a sandy limestone.

Sandy loam

This type of soil has between 0%-50% silt particles, between 50%-70% sand particles and between 0%-20% clay particles. The texture of this type of loam is something coarser than loam, but doesn't differ much.

Sandy marl

Marl is a sedimentary rock consisting of clay, claystone and limestone. Marl is a transition phase from shale to limestone. The demarcation of this rock type is not very accurate, but in The Netherlands, one speaks of marl when 25%-75% of the rock is made up of chalk. Due to the platy and weakened structure this rock erodes very easily and is very vulnerable to weathering. When a marl is composed of sand and marl particles and its main component stays marl one can speak of a sandy marl.

References

NEN-EN-ISO 14688-1:2019

Sand

Image	Sand

Contents

Sub-categories

How to determine the sandsize

Combinations

Sand with shells

Sandy gravel/gravelly sand

Sandy limestone

Sandy loam

Sandy marl

References

Sand