9 Karst Landscape
The formation of karst landscapes
Examples of karst regions in Ireland and around the
world
Distinctive landforms found on the surface and
subsurface in a karst environment
The life cycle of a karst landscape
Chapter 9: Karst Landscape
Karst topography =
An area of exposed limestone on the surface of the land
Example of karst region=
 The Burren, Co. Clare
Chapter 9: Karst Landscape
Formation
 Limestone is permeable
 Carbon dioxide (CO2) dissolves in rainwater
 Forms weak carbonic acid (acid rain)
 Carbonic acid/rainwater passes through rock – rocks
dissolved by carbonation
 Cracks in rock become enlarged
 Underground drainage system develops
Chapter 9: Karst Landscape
Chapter 9: Karst Landscape
Surface landforms
1. Limestone pavement
 Exposed area of limestone
 Rugged and bare landscape with flat areas of
rock surface
Formation
Chapter 9:weathering)
Karst Landscape
 Carbonation (chemical
 Rainwater mixes with carbon dioxide in the air
 Forms a weak carbonic acid
 limestone is dissolved
 Joints and cracks (i.e. bedding) are widened by the
rainwater
 e.g. the Burren, Co Clare
Chapter 9: Karst Landscape
Features of limestone pavements
 Clint: section of a limestone pavement separated
from adjacent sections by grikes
 Grike: vertical crack that develops along a joint
in limestone
 Karren: small hollow that forms on the surface
of a limestone clint
Chapter 9: Karst Landscape
2. Swallow holes
 River reaches an area of permeable rock
 Disappears down through grikes
 Grikes made bigger by solution (carbonation)
 Forms swallow hole (sluggas/sinkholes)
 e.g. Poll na gColm in the Burren, Co. Clare
Chapter 9: Karst Landscape
Underground landforms
1. Caves
 Swallow holes – river disappears underground
 Carbonation – passages form large caverns
 River erodes the rock of the cave by abrasion and
hydraulic action
 Carbonation and solution dissolve permeable rock
(limestone)
 Cave develops at or below zone of saturation
 e.g. Ailwee Cave, the Burren, Co. Clare; Dunmore
caves, Kilkenny
Chapter 9: Karst Landscape
2. Dripstone features
Stalactites
 Drops of water containing dissolved limestone seep down
through cracks/fissures in the cave roof
 Drops of water lose carbon dioxide and deposit calcite
 Over time deposition of calcite forms pillars hanging down
from the roof of the cave
Stalagmites
 Water droplets fall to the cave floor
 Drops of water lose carbon dioxide and deposit calcite
 Over time deposition of calcite form pillars growing
upward from the cave floor form directly below stalactites
2. Dripstone features
(continued)
Chapter
9: Karst Landscape
Pillars
 Stalactites and stalagmites grow towards each other
 Eventually join to form a pillar or column
Curtains
 Rainwater drips from a long crack in a cave roof forms a
continuous strip of calcite
• Name of
location?
• Size of area?
• When was it
formed?
• Type of rock?
• General
features?
• Famous
caves?
Chapter 9: Karst Landscape
The Burren, Co. Clare
 Covers approximately 250 square km of north-west Clare
 Formed during the carboniferous period, 355 to 290
million years ago
 Formed of limestone rock
Features include:
• Limestone pavements
• Subsurface and dripstone features
• e.g. Ailwee Cave
Chapter 9: Karst Landscape
Cycle of erosion in a karst topography
 Three stages:
 Youthful
 Mature
 Old age
Over ground features
Type of rock
Underground features
Type of weathering
Famous example