Freshwater Lake Formation

Question 1

What is a definition of a lake?

Answer 1

-A slow flowing or non-flowing open body of water in a depression, not in contact with the ocean encircled by land, and whose outflow, is small relative to its volume

Question 2

What does Lentic system mean?

Answer 2

-Standing waters

Question 3

Where are freshwater lakes predominately located?

Answer 3

Northern Hemisphere, temperate and subarctic regions

Question 4

What is lake formation dependent on?

Answer 4

1. Presence of a depression (basin)

2. Supply of water to collect in it

Question 5

What are the five dominant lake formation types?

Answer 5

1. Tectonic
2. Volcanic
3. Glacial
4. Fluvial
5. Damming

Question 6

How are tectonic basins formed?

Answer 6

-Are depressions formed by movements of deeper portions of the earth’s crust- faulting

Question 7

How are graben or rift valleys formed?

Answer 7

Faulting creates depressions between the bases of single fault displacements or in down-faulted troughs

Question 8

What is an example of a tectonic lake?

Answer 8

Lake Baikal, Siberia

Question 9

What is the surface area of Lake Baikal?

Answer 9

31,000 km2

Question 10

How old is Lake Baikal?

Answer 10

25 million years old, oldest lake in the world

Question 11

How deep is Lake Baikal?

Answer 11

1,741 m, deepest lake in the world

Question 12

What does Lake Baikal have?

Answer 12

• Contains endemic flora and fauna including freshwater seal

- UNESCO world heritage site

Question 13

What can tectonic faulting cause?

Answer 13

Moderate uplifting of the marine seabed’s or mountain ranges- upwarping

Question 14

How many meters is the Caspian sea above sea level?

Answer 14

27 meters above sea level

Question 15

What happened to the Sea of Aral in the Middle East?

Answer 15

• It was once the largest lake in the world (68,000 km2)
• In 1960s, waters were drained to irrigate the desert for fruit and vegetables
• In 2008 a dam was built to restore water levels, now. max depth 42m

Question 16

What are crater/caldera lakes?

Answer 16

Are large lake basins formed in the roofs of partially emptied magmatic chambers/cinder cones in active volcanic peaks

Question 17

Name an example of a crater lake.

Answer 17

Crater Lake, Oregon USA

• Deepest lake in US 594m
• Surface area 64 km2

Question 18

How are lava flows formed?

Answer 18

-Form when hot lava streams flow, cool and solidify creating solid dams behind which water can collect resulting in a lake

Question 19

Describe Lake Tahoe, a volcanic lake

Answer 19

• Nevada/California USA
• Surface area 496.2 km2
• Max depth 501 m
• Second deepest in USA
• 75% of lake watershed in national forest land