ITE Weathering and Caves: Karst Topography and Cave Formation
how do natural bridges form
1. several sinkholes collapse 2. river cuts a hole through a rock
aquifer
a body of rock that holds water
artesian well
a well that does not need a pump because water is forced to the surface by natural pressure since it is trapped between two layers of impermeable rock
troglobite
an animal that lives its whole life in a cave and never comes out
karst topography
an area where groundwater had dissolved bedrock
what causes geysers
an open cavity below ground fills with superheated water and then pressure forces the water through a constricted pathway
zone of aeration
area of an aquifer where pores are filled with air
zone of saturation
area of an aquifer where pores are filled with water
spring
area where the water table is so close to the surface water flows out
sink holes
areas of caves where the ceiling has collapsed
stalagmite
cave formations that grow up from the ground
stalactite
cave formations that hang from the ceiling
how do stalactites form
from the ceiling, precipitation of limestone
how do stalagmites form
from the ground, precipitation of limestone
how does the level of the water table affect springs
if the water table drops, the spring runs dry
how does the level of the water table affect wells
if the water table falls below the bottom of a well, the well runs dry
water table
line dividing the zone of saturation from aeration
what are some unique adaptations of animals that live in caves
no pigment, no eyes, sense movement, echolocation
example of porous sediments
sands where all particles are the same size, sandstone rock
example of permeable sediments
sandstone, rock with interconnected cracks
4 features of Karst topography
sinkholes, caverns, disappearing streams, natural bridges
geyser
superheated groundwater that erupts periodically from the ground
how do sinkholes form
the ceiling of a cave collapses
permeability
the ease at which water passes through sediment
porosity
the percentage of open space in a sediment
how does the level of the water table affect lakes
the water table is level with the top of the lake
how does the level of the water table affect rivers
the water table is level with the top of the river
what causes springs
the water table reaches the surface of the earth
what makes sediments permeable
they are coarse-grained (like sand--clays would be impermeable)
what makes sediments porous
they are well sorted (all the same size)
how long do formations in caves take to form
thousands to millions of years
how do caves form
water containing dissolved calcium carbonate continues to drip into the cave. When the water hits the air in the cave it forces the solution to give up some of its carbon dioxide and a precipitation of limestone forms.
how does a column in a cave form
when a stalactite and a stalagmite grow together
