Geoscience Reference
In-Depth Information
Table 2.9
Classification of peat in ASTM according to fibre content, ash content and acidity (ASTM,
1990).
Fibre content
Fibric: Peat with greater than 67% fibres
(ASTM D1997)
Hemic: Peat with between 33% and 67% fibres
Sapric: Peat with less than 33% fibres
Ash content
Low ash: Peat with less than 5% ash
(ASTM D2974)
Medium ash: Peat with between 5% and 15% ash
High ash: Peat with more than 15% ash
Acidity
Highly acidic: Peat with a pH less than 4.5
(ASTM D2976)
Moderate acidic: Peat with a pH between 4.5 and 5.5
Slightly acidic: Peat with a pH greater than 5.5 and less than 7
Basic: Peat with a pH equal or greater than 7
4. Principal plant components, namely coarse fibre, fine fibre, amorphous
5. Organic content as percentage of dry weight, determined from loss of ignition at
450-550
◦
C as percentage of oven-dried mass at 105
◦
C.
6.
Liquid limit and plastic limit.
7.
Fibre content determined from dry weight of fibre retained on #100 sieve
(
>
0.15mm) as percentage of oven-dried mass.
We will discuss this in detail in Chapter 3.
2.4 DEVELOPMENT OF PEAT LAND
The simple definition of a peat land is an area where peat is found. On the Irish Envi-
ronment and Heritage Service website (www.peatlandsni.gov.uk), peat lands, mires,
bogs and fens are defined as follows:
•
Peat land
An area with a naturally accumulated peat layer at the surface
•
Mire
A peat land where peat is currently forming and accumulating
•
Bog
A peat land which receives water solely from rain and/or snow falling on its
surface. Raised bogs are found in lowland areas, generally below 150 m, such as
river valleys, lake basins, and between drumlins. They are known as raised bogs
because the bog surface is raised in the middle, like a dome. The surface of a
raised bog is a mixture of pools, raised mossy hummocks and flatter lawns, and
is colonized by plants and animals adapted to the acidic conditions and low levels
of nutrients found there.Blanket bogs usually form in upland areas above 200m
with heavy rainfall and low temperatures. Because of the undulating nature of this
ground, the thickness of peat can vary between 1m and 6m. Like raised bogs,
blanket bogs receive their nutrients from rainwater and the atmosphere, and are
also acidic.
