Karst Processes and Landforms

Objectives

• Discuss processes producing karst landscapes and influencing environmental factors

• Analyze landscapes characterizing karst landscapes and describe their formation

• Relate karst process to development of undeground cave systems

Introduction

• Through dissolution of rocks landscapes are formed

• Karst is name for landscapes and landforms produced and processes causing them

• Most karst landforms beneath ground– Limestone caves are examples

Karst Processes

• Rock must be soluble in water– Most karst develop in limestones• Limestone must be less than 20-30% other minerals• More porosity favors karst

– Also in gypsum, dolomite, even sandstone

Role of Water and Climate

• Karst forms slowly in dry climates, faster in humid one

• Carbonation is important process– More CO2 in water favors dissolution

Relief• Flat rocks slow underground drainage and karst

development• High relief causes more rapid water movement• Deepening valleys lower water table causing varying levels

of karst

Groundwater

• Karst forms large pathways for rapid groundwater flow

• Dyes can trace water flow

• Contaminants move quickly

Karst Landforms and Landscapes—Temperate Karst

• Slower forming karst with:– Disappearing

streams– Jagged rock masses– Solution

depressions– Extensive cave

networks

Karst Landforms and Landscapes—Tropical Karst

• Rapidly forming karst characterized by:– Larger solution features– More vegetation cover• More organic acids and biogenic action

– Steep sided hills

Karst Landforms and Landscapes—Caribbean Karst

• Forms in few locations such as Florida

• Hills feed water to flat lying limestones near sea level– Conduits form. Collapse

form surface depressions

Disappearing Streams and Sinkholes

• Streams disappear in swallow holes– Holes formed by dissolution

along fault or joint• Solution sinkholes may be

large and area may contain thousands

• Collapse sinkholes form through collapse of roof– Include collapse and suffusion

sink– Two or more sinkhole coming

together form large depression called uvala

Karst Towers

• Cone-shaped, steep-sided hill

• Main feature in tropical karst

• Maybe 100s of meters tall• Form through lack of soil

and vegetation cover on parts of limestone bedrock– Surrounding area lowered

through dissolution

Karst and Caves• Form through dissolution

along joints/fractures– Consist of portal and

termination– Cave network depends on

stratigraphy, faulting, jointing– Large areas form chambers

or rooms– Stalactites (hanging) and

stalagmites (standing) form