Page 8 - Curriculum Visions Dynamic Book. To close the book, close the tab.

Bed Bed
A layer of sediment. It may be produced by a long or a short time during which sand, silt, or clay settles out. The start and end of a bed are marked by a bedding plane.
(See also: Chalk; Cross- bedding; Current bedding; Facies; Formation; Halite.)
Bedding plane
An ancient surface marking the meeting point between layers, or beds, of sediment. Sedimentary rocks often
split along bedding planes.
B horizon
A word used by soil scientists
to describe the subsoil. The B horizon does not contain humus. It is therefore usually a much lighter colour than the humus-rich A horizon, or topsoil.
The B horizon is the place where the taproots of plants are found, while the fine, fibrous, nutrient-gathering roots of plants are found in the A horizon close to the surface.
 Bed – When beds slope, they are called dipping beds. They are clearly seen in this coastal picture.
The B horizon may contain deposits of minerals or clay washed out of the A horizon. One of the most distinctive of these layers in a B horizon is called an iron pan. It is a layer so rich in iron that it forms a brittle sheet that will not let water through. Iron pans of this kind form in podzol soils. An even thicker layer of iron occurs in a tropical soil known as a laterite. (See also: Horizon.)
 Beryl – Beryl is a green mineral whose crystals have a hexagonal shape.
Beryl
A glassy-green mineral. The name beryl comes from the Greek word beryllos, meaning a ‘green gem’.
It is often found in large pieces, sometimes several metres long.
(See also: Hexagonal.)
 Biotite –
Biotite is the black
form of mica that is
found in many igneous rocks.
Biotite
A black form of the mineral mica. Biotite is an important mineral
in granite rocks, showing as the black flecks among the other light- coloured minerals.
Black cotton soil
(See: Black soil.)
Black soil
A term covering two different types of soil. It is used for the soils with deep humus-rich topsoils such
as chernozems. It is also used
for deep soils such as black
cotton soils (also called vertisols) that develop in subtropical regions over basalt and other clay-rich materials. In general, the black colour is produced by humus staining and so all types of black soils are fertile.
8