Section 10.2
Groundwater Weathering and Deposition
Carbonic Acid
Most groundwater is slightly acidic due to
carbonic acid.
Carbonic acid forms when carbon dioxide
gas dissolves in water and combines with
water molecules.
Section 10.2
Groundwater Weathering and Deposition
Dissolution by Groundwater
The processes of dissolving, called
dissolution, and precipitation of calcite both
play a major role in the formation of
limestone caves.
Section 10.2
Groundwater Weathering and Deposition
Dissolution by Groundwater
Caves
A natural underground opening with a
connection to Earth’s surface is called a
cave or cavern.
Section 10.2
Groundwater Weathering and Deposition
Dissolution by Groundwater
Caves
As groundwater infiltrates the cracks and
joints of limestone formations, it gradually
dissolves the adjacent rock and enlarges
these passages to form an interconnected
network of openings.
CAVES: CARLSBAD CAVERNS
CAVES: MAMMOTH CAVE
Section 10.2
Groundwater Weathering and Deposition
Dissolution by Groundwater
Karst topography
A sinkhole is a depression in the ground
caused by the collapse of a cave or by
the direct dissolution of limestone by
acidic water.
KARST TOPOGRAPHY
KARST TOPOGRAPHY
Section 10.2
Groundwater Weathering and Deposition
Dissolution by Groundwater
Karst topography
Limestone regions that have sinkholes and
disappearing streams are said to have
karst topography.
KARST TOPOGRAPHY
SINKHOLES
SINKHOLES
CH
Study Guide
Key Concepts
Section 10.2 Groundwater
Weathering and Deposition
Chemical weathering of limestone
by water causes the characteristic topography
of karst areas.
 Groundwater dissolves limestone and forms
underground caves.
 Sinkholes form at Earth’s surface when
bedrock is dissolved or when caves collapse.
CH
Study Guide
Key Concepts
Section 10.2 Groundwater
Weathering and Deposition
 Irregular topography caused by groundwater
dissolution is called karst topography.
 The precipitation of dissolved calcite forms
stalactites and stalagmites in caves.
CH
Groundwater
10.2 Section Questions
Which statement describes a stalactite in a cave?
a. It builds up from the floor.
b. It connects floor and ceiling.
c. It hangs from the ceiling.
d. It builds on a wall.
CH
Groundwater
10.2 Section Questions
How does a sinkhole form?
Possible answer: A sinkhole may form as
the roof of a cave collapses. A sinkhole may
also form where dissolution of limestone
occurs at the surface. This may happen if a
particular location is affected by more water,
is affected by more acidic water, or if the
rock is more vulnerable to dissolution.
CH
Groundwater
10.3 Section Questions
Pumping too much groundwater can cause
the land surface to sink.
a. true
b. false
CH
Groundwater
Chapter Assessment
Questions
Which terms best describe a region of
karst topography?
a. flat and featureless
b. sinkholes and caves
c. steep and mountainous
d. rolling and hilly
CH
Groundwater
Standardized Test
Practice
Which positive ion enters groundwater as a
result of the dissolution of limestone by
carbonic acid?
a. sodium
b. calcium
c. potassium
d. lithium