Chapter 13 - Karsts and Caves

Question 1

Define Karst (review)

Answer 1

Karst
is a terrain with distinctive characteristics of
relief and drainage, including caves, sinkholes, underground streams, caverns, arising primarily
from the solution of soluble bedrock by natural waters

Question 2

Define Soil (review)

Answer 2

Soil
is a naturally occurring, unconsolidated or
loose material on the surface of the earth, capable
of supporting life. Soil has three components: solid,
liquid, and gas
.

Question 3

Define Regolith (review)

Answer 3

is the layer of
loose, heterogeneous material covering solid rock. It
includes dust, soil, broken rock
(blanket rock)

Question 4

Define Weathering (also mechanical and chemical) [review]

Answer 4

Weathering
-Weathering is the mechanical breakdown and chemical
a
lteration of rock and sediment when exposed to air,
moisture, and organic matter.
Weathering is “mechanical (physical)” or “chemical”.
Mechanical (physical) weathering
-mechanical disintegration of rocks
Chemical weathering
-decomposition of rocks and sediments via chemical (and microbial) reactions that dissolve minerals

Question 5

Main products of (chemical?) weathering

Answer 5

Silicates: Regolith and soil
Carbonates: Kart + Caves

Question 6

Earliest life forms that lived in caves? What do caves tell us about them (evidence) ?

Answer 6

Neanderthals

-cave paintings, 30k to 40k years ago

Question 7

Define cave

Answer 7

natural opening in rock large enough for man to fit through

Question 8

Stages of cave formations:

Answer 8

2 stages:

1) Cave formation via DISSOLUTION below groundwater table
2) formation (DECORATION) forming above groundwater level

Question 9

Stage 1 of cave formation) Dissolution wrt caves

Answer 9

Caves form as a result of the dissolution of carbonate rocks by slightly acidic water

Question 10

Dissolution; through groundwater

Answer 10

Note; slightly acidic groundwater

• groundwater dissolves carbonate rocks and gradually forms a system of passageways
• groundwater then moves along surface of water table, forming system of horizontal passageways
• as surface streams erode deeper valleys, water table drops, and abandoned channelways form and interconnecting system of caves and rocks

Question 11

Stage 2 of cave formation) Decoration wrt caves; what are features, how are they made?

Answer 11

-drop of water evaporates in cave
-water drops in from top, first thing that forms is a ring of calcium carbonate that grows downwards
-eventually grows to considerably long length, grows longer and longer
-essentially reading the equation CO2 + H2O –> H2CO3, but backwards
Stalagmites are from bottom up
Stalactite are from top - bottom

Question 12

How do hybrid caves form? What are features of them?

Answer 12

When sea levels rise due to high tides, cut open an older cave that was higher up
This washes out those cavees, creates a hybrid cave
-they have odd columns, they are weak, doesn’t take much to break

Question 13

How are sea caves made? Max length?

Answer 13

Corrasion - mechanical erosion of earths surface caused when materials are transported across it by running water, waves, glaciers, wind (think pseudo karst)
-300m max length

Question 14

Caves made from mechanical weathering

Caves made from chemical weathering

Answer 14

Mechanical weathering:
sea caves
Chemical weathering:
caves made from dissolution(Carbonate with HCL)

Question 15

define karst

Answer 15

Area of irregular limestone where dissolution produced fissures, sinkholes, underground streams, and caverns

Question 16

What are sinkholes? How are they formed?

Answer 16

sub circular depressions. USUALLY Formed by dissolution of carbonate rocks (exception: Pseudo sinkholes)

Question 17

What are pseudo sinkholes

Answer 17

Sinkholes that are not formed from dissolution of carbonate rocks

Question 18

What are collapse sinks? How are they related to tower karst?

Answer 18

When sink holes sink down into cave system, widen channels for rain water to go down into groundwater, wider and wider opening

• all that is left is a column/tower of carbonate rocks
• the tower of corbonate rocks is a Tower Karst

Question 19

What are solution valleys?

Answer 19

When sinkholes connect through dissolution and they merge together
-will get flooded during heavy rainfall

Question 20

What are sinking streams?

Answer 20

Streams that just disappear from surface and go into ground

Question 21

Karstification - epigene vs hypogene cave systems

Answer 21

Epigene:
Rain water comes down, goes through rock, dissolving through passage way, have an epigene cave system, the water eventually goes underground and goes out to ocean
-on surface of earth
Hypogene:
water that dissolves cave systems come from BOTTOM UP, tends to be mazes instead of like stream caves where they just go down cave
-multiple layers of caves
-under surface of earth

Question 22

What is epigene?

Answer 22

processes that are controlled from top down

-on surface of earth

Question 23

What is hypogene?

Answer 23

Processes that are controlled from bottom up

-under surface of earth

Question 24

Sinkholes in Barbados?

Answer 24

gullies - landform created by running water, eroding into soil
-resemble large ditches or small valleys

2830 sinkholes in Barbados!!
diameter: 9m to 120m

Question 25

How are stalagmites useful? What can they help identify? Talk about climate of fresh water caves

Answer 25

remember stalagmites are floor up

• they have growth rings like trees
• we can use as an estimation of paleo-climate
• allows us to tell how cold or how wet it was in past climates

For fresh water caves:
-caves are always same temperature year round

Question 26

Define pseudo karst

Answer 26

karst that is not formed by dissolution of carbonate / limestone

Question 27

Biggest cave in the world??

Answer 27

Vietnam: Hang Son Dooong (mountain river cave)

-4km x 100m wide up to 300m high

Question 28

Deepest cave in the world??

Answer 28

Georgia: Krubera cave

2197m

Question 29

What is bioerosion

Answer 29

removal of calcium carbonate by biological agents (instead of dissolution)

• so its organisms living on rocks, that want to eat algae, so they eat through the rock to get through algae
• generate tiny holes, sea caves, create micro karsts