Water%20Erosion:

1

• Water Erosion
• How do processes involving water change Earths
  surface?
• Part 3

2

• What results from water in the atmosphere mixing
  with CO2 (carbon dioxide) ?
• Acid Rain

3
Precipitation and Groundwater

• Water in the atmosphere combines with carbon
  dioxide (CO2) to form a weak acid known as
  carbonic acid. Another term for this is acid
  rain.
• When the precipitation falls on Earths surface,
  the water that does not evaporate back into the
  atmosphere or runoff the surface can sink into
  the ground.
• Water that soaks into the ground is known as
  groundwater, and becomes part of the groundwater
  system.

4
Groundwater Weathering

• Groundwater weathers rocks which contains CaCO4
  (calcium carbonate). Examples of this type of
  rock are limestone, marble, and chalk).
• The groundwater (weak carbonic acid) dissolves
  those rocks in the process of chemical weathering.

5
Groundwater Erosion

• As the rock dissolves, it goes into solution with
  the groundwater, and flows along with the
  groundwater.
• This underground movement of chemically weathered
  rock is known as groundwater erosion.
• This process will gradually hollow out pockets in
  the rock.
• Over time, the pockets develop into large holes
  called caves or caverns.

6

• Cave Formations
• How do they form?

7
Groundwater Deposition

• Once the cave or cavern is established
• the groundwater solution can drip from the
  ceiling to the floor.
• Evaporation occurs as the solution slowly drips
  from the ceiling. Evaporation also occurs when
  the solution has fallen to the floor.
• As the water evaporates
• the minerals (such as calcite) in the solution
  will be left behind (or deposited) hardening on
  the ceiling and floor of the cave or cavern
  causing cave formations.

8

• Cave Formations
• What are the features found in a cave?

9
Cave Formations

• What are stalactites?
• Calcite deposits that hang from the caves roof
  like icicles
• What are stalagmites?
• Cone-shaped calcite deposits that build up from
  the cave floor

10
Ellisons Cave in Walker County, Georgia

• http//www.georgiaencyclopedia.org/nge/Article.jsp
  ?idh-2130

http//www.georgiaencyclopedia.org/nge/Article.jsp
?idh-2130
11

• Karst Topography
• What happens when land rich in limestone is
  weathered and eroded by groundwater?

12
Sinkholes

• Sinkholes are
• depressions in the ground.
• Sinkholes are caused when
• the roof of a cave or cavern collapses because
  of the erosion of the underlying rock (limestone)
  with the result being the depression.
• Sinkhole Formation Animation

13
Karst Topography

• A Karst Topography is
• A type of landscape
• Karst Topography is created in regions where
• a layer of limestone near the surface forms
  deep valleys, caves, caverns, and sinkholes.

14
Karst Topography
http//www.virginiacaves.org/lok/ccvup56.jpg
15
Karst Topography
http//4.bp.blogspot.com/_JRp7TJWTx4A/S8Z8B2hEMVI/
AAAAAAAAAVk/h0MJosarOQ0/s320/karst_cave.jpg