Title Page Photo
“Come forth into the light of things,
Let Nature be your teacher.”
—William Wordsworth
Solution Processes and
Karst Topography
 The Impact of Solution Processes on the
Landscape
 Solution and Precipitation
 Caverns and Related Features
 Karst Topography
 Hydrothermal Features
 The Impact of Solution Processes on
the Landscape
• Underground Water
– Slightly Acid (e.g. carbonic acid – H2CO3)
– Dissolves certain rock-forming chemicals,
especially calcium and magnesium carbonates
• Effects of Solution on the Landscape
– Karst topography
– Hydrothermal surface features
Karst Topography
(Rolling landscape and sink holes)
 Solution and Precipitation
• Dissolution – Process of going into solution
– Solubility varies among different elements
Most
soluble
in H2O
Least
soluble
in H2O
– Fig . 17-1
 Solution and Precipitation
• Example of dissolution: Carbonate Rocks
– They are common rocks and highly soluble
Dissolution (breakdown of minerals) → Solution (salts dissolved in water)
CaCO3
calcium
carbonate
+
H 2O
water
+
CO2
carbon
dioxide
CaMg(CO3)2 +
dolomite
2H2O
water
+ 2 CO2 →
carbon
dioxide
→
Ca(HCO3)2
calcium
bicarbonate
Ca(HCO3)2 + Mg(HCO3)2
calcium
magnesium
bicarbonate bicarbonate
• Role of Bedrock Structure
– Joints becomes solution pathways
– Network of solution tubes widen to form small
rooms and large caverns (large rooms)
– Fig. 17-2
 Caves and Related Features
• Location
– Usually found where there is massive limestone
bedrock, and plentiful underground water
• Formation: Two-stage process
– Initial excavation stage by solution action
– “Decoration stage” by precipitation of minerals
• Speleothems: e.g., stalagmites, stalactites, and pillars
– Fig. 17-4
 Caves and Related Features
– Precipitate formations
• Speleothems
– Decorative features formed from
deposits
– Precipitated mineral deposits
are usually calcite.
– On walls, roofs, floors of caves
(a)
– E.g., flowstone on cavern ceiling (a)
and wall (b), Lost River Caverns,
Hellertown, PA (Richard A. Crooker
photos)
(b)
– Fig. 17-3. Speleothems such stalactites hang from the ceiling of
this room in New Mexico’s Carlsbad Caverns. Some of them
have joined with stalagmites to form pillars. You’ll find similar
formations in the Mammoth Cave National Park, Kentucky.
 Karst Topography
• ‘Karst’
– Ancient Slavic word (Germanized), meaning
“barren land”
– Name of Karst region of the former Yugoslavia with
this kind of topography
• Topography
– Rugged hilly area shaped by solution of limestone
(sometimes contains dolomite, gypsum, or halite).
See next slide.
– Fig. 17-5. Namesake karst region of former
Yugoslavia.
– Extent: 10% of Earth’s land area has soluble carbonate rocks
at or near surface. In the U.S. lower 48 states, it’s 15%.
Limestone leads to Karst Regions.
– Fig. 17-6
*Notable in Karst Landscapes are the absence of
surface streams. They’re sometimes “lost rivers”.
See next slide.
Lost River Cave & Valley, Bowling Green, Kentucky
Spring
• Surface features
– Early development: sinkholes (or dolines) and
disappearing streams (a.k.a. “lost rivers”).
– Fig. 17a
– Advanced development: sinkholes (or dolines),
collapse dolines, and uvala (chain of intersecting
sink holes).
– Fig. 17b
– Tower Karst (late development): haystack hills
(mogotes) and exposure of non-soluble bedrock
– Fig. 17-7c
– Fig. 17-8. Tower karst in Guilin, China.
• Sinkholes as Natural Hazards
– Fig. 17A. This sinkhole swallowed a house in central Florida.
Precipitation Processes
– “Precipitation” in this sense, means the
elements recombine, and are removed
from water and deposited. Here, it has
nothing to do with “rain”.
– Caves, geysers and hot springs
encourage these deposits, as the
pressure in caves drop, or as
temperatures drop around the lip of a
hot spring.
• In caves, air pressure is lower than
in joints and bedding planes.
• In geysers and hot springs, air
pressure drops suddenly, and there
is also rapid heat loss to air. Think
of the mineral ‘ring’ that is left
behind in a pot when you boil water.
– Fig. 17-12. Geyser with a
nozzle in Yellowstone
National Park, Wyoming.
 Hydrothermal Features
• Hot Springs
– Eject hot water
– Source is volcanic heat
and pressure
– Calcium carbonate
precipitates when water
reaches surface
– Calcium carbonate
deposits could be:
• Travertine (massive)
• Tufa (porous)
– Fig. 17-9
– Carbonate terraces accrete around hot springs
– Fig. 17-10. Hot spring atop a carbonate terrace in Yellowstone
National park. Algal growth highlights the spring.
– Travertine terraces (hot spring is on top of terrace
and out of view)
– Fig. 17-17. Mammoth Hot Springs, Yellowstone
National Park, WY; Fig. 17-16
• Geysers
– A hot spring that is intermittent
– Usually hot water ejects
(erupts) sporadically instead of
flowing continuously. It’s a
temporary eruption that reverts
to dormancy, and then the
cycle starts again
– Shoots up into the air; this
eruption releases pressure
build-up within a restricted
subterranean tube.
– Fig. 17-11. Old Faithful
geyser in Yellowstone
National park.
• Fumaroles
– Unlike a geyser, very little water drains into the tube of a
fumarole
– It’s a hot spring that lacks water; it sends out only steam
– Fig. 17-13.
• Yellowstone National
Park, Wyoming
– America’s showcase of
hydrothermal features
– Fig. 17-15. Yellowstone
National Park and its major
geyser basins.