Download Welcome to the Burren-- a wonderful example of Chemical Weathering

Chemical Weathering
as we know it

Chemical Weathering causes
rock to dissolve or otherwise
decompose
 What is the main cause (agent)
of chemical weathering?
Chemical Weathering in the Tropics

Chemical weathering is
weathering that causes
any kind of chemical
change to the rock.
 The reddish-orange colour
of the soil is a result of
oxidation, a chemical
weathering process much
like the rusting of iron.
 What is the main agent for
chemical weathering?
 Why would the tropics
have a lot of chemical
weathering?
Erosion in the Tropics

Rainforest soils are very
fertile.
 Trees are harvested and
sold or cut and burnt in the
hope of creating fertile farm
land to grow crops and
graze cattle.
 . These efforts often fail
resulting in
eroded, useless
land.
Who do you
think
benefits?
Rainforests in the World
Welcome to the Burren-a wonderful example of
Chemical Weathering
Where is the Burren?
Burren comes from
the Irish word
‘Boireann’ meaning
‘rocky country.’
Formation of the Burren
 Once
upon a time the Burren was lightly
wooded and covered with soil.
 Toward the end of the Stone Age, about
6000 years ago, the nomadic huntergatherers began to settle and farm.
 To do this they cut the trees and used the
hills for grazing and growing crops.
 What do you think happened?
Karst Landscape
The name Karst
comes from a
limestone area
in Western
Slovenia with
that name.
How Rain Weathers Limestone




Carbon Dioxide
Mixes with Rain to
form a weak
Carbonic acid
Limestone is a
Permeable Rock
The rain water
seeps through weak
points, vertical joints
and horizontal
bedding planes
dissolving tiny
particles of calcium
carbonate and
taking it away.
This process forms
caves.
Surface Features

Bare Rock
 Gently sloping
terraces
 Sudden cliffs
Limestone Pavements

Clints and Grikes
Clints are the flat topped slabs
Grikes are the cracks between
Rivers can not flow on the surface
for long. They disappear into
Swallow Holes and leave
Dry Valleys behind
Maps and Swallow Holes
 Look
at this
map for
rivers that
just stop
 Where do
you think the
Swallow
Holes are?
Pollnagollum in the Burren

The swallow hole
Pollnagollum is
6 meters wide and
16 meters deep.

It is the entrance to
Ireland’s longest
cave system.

Over 7 Km have
been explored.
This picture shows a fenced off,
collapsed subsidiary entrance to
Pollnagollum.
In this photo
look for the
vertical joints
and horizontal
bedding planes
of the limestone
where the rain
seeps through
The Burren– Continued
Underground Features
Underground Rivers Form
Passages and Caves
Features of Caves
Underground Passages and
Caverns
How cave features are formed

Evaporation of water
dripping through the cave
leaves behind tiny particles
of calcite earlier dissolved
from the rock.
 Stalactites form from water
dipping from the ceiling.
 Stalagmites form when the
water drops and then
evaporates from the floor.

It can take over 100 years for a stalactite to grow
5cm.
Stalactites Stick Tight
to the Ceiling
Stalagmites Grow from the Floor
When Stalactites and Stalagmites
Grow Together they Become
Pillars
Other Cave Features
“Niagara Falls”
Soda Straws
Curtain
Popcorn
Closer to HomeMitchelstown Caves
Why is the Burren Special?

Potholers and Cavers explore underground.
 Geographers study the limestone features.

Historians and
archaeologists
appreciate the medieval
ruins, ring forts, ancient
burial chambers, castles,
and scenic villages.
 Tourist enjoy the
unusual Karst Scenery
and sites like the Cliffs of
Moher, Ailwee Cave,
and walking on the
‘Green Roads.’
Botanists and Naturalists

Botanists and Naturalists search for rare plants and
animals such as the Pine Martin.
 The Burren hosts 1,100 of the 1,400 species of
plants found in Ireland.
 Typical Irish plant species are found as well as Alpine
and Mediterranean species left from geologic history.
Mullaghmore in
The Burren National Park
-The Controversy-
Note the many turloughs in the photo. Turloughs are seasonal lakes
which empty and fill with the changing ground water levels.
What do you think?