The formation of karst landscapes Examples of karst regions in Ireland and around the world Distinctive landforms found on the surface and subsurface in

The formation of karst landscapes The formation of karst landscapes

Examples of karst regions in Ireland and around the Examples of karst regions in Ireland and around the world world

Distinctive landforms found on the surface and Distinctive landforms found on the surface and subsurface in a karst environment subsurface in a karst environment

The life cycle of a karst landscape The life cycle of a karst landscape

99 Karst LandscapeKarst Landscape99 Karst LandscapeKarst Landscape

Chapter 9: Karst LandscapeChapter 9: Karst Landscape

Karst topography =Karst topography =

An area of exposed limestone on the surface of the land


Example of karst region= The Burren, Co. Clare


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


SurfaceSurface landformslandforms

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

surface


Formation Carbonation (chemical weathering) 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


Features of limestone pavementsFeatures 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


2.2. Swallow holes 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


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


2. Dripstone features

StalactitesStalactites 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

StalagmitesStalagmites 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

Chapter 9: Karst LandscapeChapter 9: Karst Landscape 2. Dripstone features (continued)

PillarsPillars

Stalactites and stalagmites grow towards each other

Eventually join to form a pillar or column

CurtainsCurtains

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?


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


Cycle of erosion in a karst topography Three stages:

Youthful Mature Old age

Over ground features Underground features

Type of rock Type of weathering Famous example

Documents

The formation of karst landscapes Examples of karst regions in Ireland and around the world Distinctive landforms found on the surface and subsurface in