1. 5th year Geography Ms Carr
Karst Landscapes
5th year Geography
Ms Carr

2. Learning Outcome
Understand the processes involved in the formation of Karst Landscapes.
List examples of Karst regions.
Describe the surface and underground landforms in a Karst region.
Explain the life cycle of a Karst landscape.

3. Karst topography Exposed limestone Landscape created by water
Dissolving of carbonate rock

4. Examples of Karst Regions
The Burren, Co Clare
Marble Arch, Co Fermanagh
Kras, South-West Slovenia
Guilin, Guangxi Region, China

5. Limestone & Carbonation
Limestone is permeable
Rain takes in carbon dioxide as it passes through the atmosphere
Carbon dioxide (CO2) dissolves in rainwater (H2O)
Forms weak carbonic acid (H2CO3)
The carbonic acid reacts with the calcium carbonate (CaCO3) in the limestone
This forms calcium bicarbonate (Ca(HCO3)2), which is soluble in water
This solution percolates through rock
It removes the calcium carbonate
Fissures in rock become enlarged
Underground drainage system develops

6. Karst Landscapes
Surface Landforms

7. Limestone pavement Exposed area of limestone
Rugged and bare landscape with flat areas of rock surface

8. Formation of a Limestone Pavement
Carbonation (chemical weathering)
Rainwater mixes with carbon dioxide in the air
Forms a weak carbonic acid
More carbon dioxide is absorbed when the water percolates through the soil
Solution; water containing the carbonic acid dissolves the permeable limestone
Joints and cracks (i.e. bedding) are widened by this process
e.g. the Burren, Co Clare

9. 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

11. Swallow Holes
A river disappears underground in a limestone region

12. Formation of 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

13. Dry valley = remains of river valley downstream from sinkhole2.
Dry valley = remains of river valley downstream from sinkhole
River of resurgence = where river reappears at the surface

14. Pairwork Quick Questions
Explain the process of carbonation.
Explain the term ‘permeable’.
Name two surface landforms in a limestone region.
Which part of the limestone pavement would you walk on?
Give two other words used to describe a swallow hole.

15. Learning Outcome Lesson 2 Recap on Karst landscapes & examples
Recall the surface landforms in a Karst region
Complete & Label diagram showing all Karst features
Watch video clips explaining the formation of Karst landforms
Homework; Page 84 Q 1, 2 & 3.

16. Karst Landscapes
Video Clips

17. Underground Landforms
Karst Landscape
Underground Landforms

18. 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
Zone of Saturation is the soil or rock below the water table, all spaces there are permanently filled with water

19. 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 the stalactites hanging down from the roof of the cave
Stalactites are hollow mineral tubes, like drinking straws
They are very thin and fragile
Stalagmites
Water droplets fall to the cave floor
Over time deposition of calcite form the stalagmites growing upward from the cave floor form directly below stalactites
Stalagmites are thicker than the stalactites

21. 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

22. Subsurface and dripstone features e.g. Ailwee Cave
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

23. Pairwork; OS Map Task OS Map of the Burren Area, page 82
Give a grid reference for the Ailwee area
Identify the height of the limestone terrace shown on the map
Locate and identify two swallow holes found on this OS map extract

24. Cycle of Erosion in a Karst Topography
Three stages:
Youthful
Mature
Old age

25. Youthful stage
Rivers flowing on the surface
Erosion of impermeable rock
Then erosion of permeable rock (limestone)
Chemical weathering (carbonation)
Formation of swallow holes

26. Mature stage
Dry valleys on the surface
Swallow holes

27. Older more resistant rock left prominent – hums
Old age stage
Weathering
Removal of limestone
Older more resistant rock left prominent – hums
Rivers once again flow over the surface
Hums- Rocks that stand out on the landscape

28. Quick Revision Questions
Name the main weathering process effective on limestone
List the three parts of a limestone pavement
Name another surface landform found in a limestone region
Name four underground landforms in a limestone region
Describe a stalactite

29. Exam Questions
With reference to the Irish landscape, examine how the process of weathering has influenced the development of any one limestone feature. (30m)
Examine with reference to an example you have studied, the formation of one rock type and how it produces a distinctive landscape. (30m)
Explain with the aid of diagrams, how any two underground landforms, found in a Karst region are formed. Give a named example of each in your answer. (40m- OL)