GCSE CHEMISTRY - Examples of Sedimentary Rocks - Limestone - Chalk - Coal - Rock Salt

gcsescience.com 11 gcsescience.com

conglomerate, sandstone, mudstone, shale

and see below for
limestone, chalk, coal and rock salt.

What is Limestone?

Limestone is an example of a sedimentary rock
that has not formed from the processes of weathering.
Limestone comes from the remains of millions of sea creatures
that have died and fallen to the bottom of the sea.

The creatures themselves have decayed but their shells
and skeletons remain. Compaction over millions of years
turn these remains into limestone rock.
Limestone is mainly calcium carbonate. It has many uses.

Other examples of sedimentary rock
not formed by weathering are chalk, coal and rock salt.

What is Chalk?

Chalk is a very pure form of calcium carbonate,
and is made in a similar way to limestone.

What is Coal?

The formation of coal is outlined in the section Products from Oil.

What is Rock Salt?

Rock salt is formed from salts which have crystallised out
of sea water as the water has evaporated - see also sea salt.
The process is the same as that given for
general crystallisation where evaporation of water from
a saturated solution causes the salt to crystallise.

The salt crystals will then settle as a sediment,
and compaction turns the salt into a sedimentary rock.
Rock salt (which is mainly sodium chloride) can be extracted
by mining or by dissolving it in water and then extracting
the brine through a pipe and allowing the salt to evaporate.

Links Sedimentary Rocks Revision Questions

gcsescience.com The Periodic Table Index Rocks Quiz gcsescience.com

Home GCSE Chemistry GCSE Physics