The Solid Earth - Chapter 3: Geologic Work of Groundwater

Question 1

The primary erosional work carried out by groundwater is that of ____ rock

Answer 1

dissolving

Question 2

Name a rather soluble rock

Answer 2

limestone

Question 3

Although nearly insoluble by H2O, limestone is quite easily dissolved by water containing small quanities of ________

Answer 3

carbonic acid

Question 4

What forms when groundwater comes in contact with limestone because of the calcite in the rocks and the carbonic acid in the rain?

Answer 4

Calcium bicarbonate

Question 5

True or false: calcium bicarbonate is soluble

Answer 5

True

Question 6

In the US about 17,000 ____ have been discovered

Answer 6

Caves

Question 7

Most caverns are created at or below the water table in the ___ ___ _____

Answer 7

zone of saturation

Question 8

In the Zone of Saturation, acidic groundwater follows lines of _____ in the rocks

Answer 8

weakness

Question 9

As time passes, the dissolving process from acidic groundwater slowly creates cavities that gradually enlarge into ____

Answer 9

caverns

Question 10

Material that is dissolved by the groundwater is carried away and discharged into _____

Answer 10

streams

Question 11

The name for cave deposits from dripping water

Answer 11

dripstone

Question 12

The deposition of dripstone is not possible until the caverns are above the water table in the ____

Answer 12

zone of aeration

Question 13

These icelike pendants hand from the ceiling of the cavern and form when the water seeps through cracks above

Answer 13

Stalactites

Question 14

When water reaches air in a cave, some the dissolved CO2 escapes from the drop and ____ begins to precipitate

Answer 14

calcite

Question 15

True or false: a limestone tube created by drops piling in deposition is solid

Answer 15

False; it is hollow

Question 16

A stalactite that is hollow and takes the calcite from a drop but moves the water

Answer 16

soda straw

Question 17

Formations that develop on the floor of a cavern and reach upward toward the ceiling

Answer 17

Stalagmites

Question 18

Which are typically bigger and more rounded: Stalactites or Stalagmites

Answer 18

Stalagmites

Question 19

Areas that have largely been shaped by dissolving power of groundwater

Answer 19

karst topography

Question 20

Karst areas characteristically exhibit an irregular terrain punctuated with depressions called

Answer 20

sinkholes / sinks

Question 21

Two reasons sinkholes appear:

Answer 21

the limestone immediately below soil is dissolved by downward seeping rainwater that has CO2

the roof of a cavern collapses under own weight

Question 22

Karst regions show a striking lack of ______

Answer 22

surface drainage