Re: What is the difference between a 'soil' and a 'sediment'

A soil is a type of sediment, but not all sediment is soil.  Sediment 
refers to any loose natural material on the earth's surface.  Examples of 
sediments are gravel, sand, mud, soil, and even loose seashells on a beach.
Sediment is found almost everywhere on the earth's surface, including on 
the bottom of the oceans and lakes, on river beds, in sand dunes, etc.  
Soil is that sediment that is subaerial, that is, exposed to the earth's 
atmosphere.  For example, mud on the bottom of a lake or ocean is not a 
soil, but mud on land is a soil.  A soil is greatly influenced by surface 
features, such as climate and organisms.  Besides containing rock and 
mineral matter  (as all sediments do), soil often contain abundant organic 
matter. Soils usually undergo periods of wetting (due to rain and floods) 
and drying.