Caves

A cave is defined as an underground passage large enough for a person to

crawl into, naturally formed, and in complete darkness.

How does a cave form?

1. Rain dissolves Carbon Dioxide into Carbonic acid

2. Carbonic acid dissolves minerals in rock

3. Rock is sculpted in weak spots

4. Water seeps through rocks and makes underground waterways

5. When the water level drops, the waterway exits the rock through the exiting hole (resurgence)

6. Collections of water creates deep gaps in caves.

7. When the water level outside the cave drops, the cave empties and dries out.

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1405/es1405page01.cfm?chapter_no=visualization

Stalactite

Stalagmite

Column

Dissolved

Minerals

(Rock)

Stalactites

• Stalactites

– Formed by water that

drops from the top of the

cave that contains calcite

– The calcite is left when

the water drops

– Occasionally, stalactites

will grow together with the

stalagmites and will

create a column.

Types of Stalactites

• Types of

Stalactites

• Icicle Straw Drape

Stalagmites

• Stalagmites:

– Form from the bottom

of the cave

– They grow about 1 cm

every 1000 years

Types of Stalagmites

• Dish Stack Fir Cone

Three Primary Cave Types

• Rainfall

• Sulfuric Acid

• Flowing Lava

Rainfall

• Rainfall seeps into the

ground and combines

with CO2 in the soil to

make Carbonic Acid

• The Carbonic Acid

dissolves away the

limestone

• Natural Bridge

Caverns

Sulfuric Acid

• Found near

underground oil

fields

• Microbes eat

sulfates in the oil

and release a gas

that when combined

with oxygen forms

sulfuric acid

• Lechuguilla Cave

Flowing Lava

• Lava travels beneath the surface and is

expelled by a volcano during an eruption

Cave Organisms

• Cave organisms fall into three basic

classes:

– Troglophiles

– Troglobites

– Trogloxenes

Cave Organisms Troglophiles: “cave lovers” can live part or

all of their lives in caves

– Can complete a life cycle in certain

environments on the surface

– Examples: cave crickets, millipedes,

pseudoscorpions, and spiders

Cave Organisms Troglobites: “cave dwellers” animals that are

specialized for cave life.

– Can leave for short periods of time

– Can complete parts of their life cycles above ground

– Can’t live entire lives outside of the cave

– Examples: some bacteria, some flatworms, and

blindfish

Cave Organisms

Trogloxenes: “cave guests”

– Frequents caves

– May require caves for a portion of it’s life

cycle

– Must return to the surface

– Examples: Hibernating reptiles and

mammals

Adaptations of Things that Live in

Caves

• Loss of pigment

• Loss of eyes

• Blue eyes (can absorb light better)

• Elongation of appendages

• Enhancement of other senses (can sense

vibrations in water)

• Echolocation