Geoscience Reference
In-Depth Information
Sub-group and laboratory identification
Group
Sub-group
Liquid
Degree of
Field
Soils group (see note 1)
Description
Symbol
symbol
Limit %
Humification
Sub-group name
Identification
ORGANIC
SOILS and
PEATS
SLIGHTLY
ORGANIC
SOILS
Organic
Content
3-20%
Slightly
Organic
SILT
Slightly
Organic
Clay
Mo
Fo
Co
Mo
Clo
Clo
Cho
Cvo
CEo
< 35
35-50
50-70
70-90
> 90
Slightly Organic SILT (Sub-divide
like Co)
Slightly Organic CLAY of low
plasticity
Slightly Organic CLAY of
intermediate plasticity
Slightly Organic CLAY of high
plasticity
Slightly Organic CLAY of very
high plasticity
Slightly Organic CLAY of
extremely high plasticity
Usually very dark to black
in colour, small amount of
organic matter may be
visible. Often has distinctive
organic smell.
ORGANIC
SOILS
Organic
Content
20-75%
ORGANICS
SOILS
O
Subdivision of Organic Soil is
difficult, as neither the plasticity
tests nor the humification tests
are reliable for them. As such
a 'best attempt' is the probable
outcome of subdivision leading
to descriptions such as 'Fibrous
ORGANIC SOILS' or
'Amorphous ORGANIC SOIL
of Intermediate Plasticity'.
PEATS
Organic
Content
More
than 75%
PEAT
Pt
Ptf
Pth
Pta
H1-H3
H4-H6
H7-H10
Fibric or Fibrous Peat
Hemic or Moderately
Decomposed Peat
Sapric or Amorphous Peat
Dark brown to black in
colour. Material has low
density so seems light.
Majority of mass is organic
so if fibrous the whole
mess will be recognizable
plant remains. More likely
to smell strongly if highly
humified.
 
Search WWH ::




Custom Search