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2. What are the 10 major ways to create a basin?

1. Why is it important to understand a lakes morphometry?

Origins of Lake Basins

3. Where in the world are lakes most common? Why?

pp. 277-287 in Dodson

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The lake must be in a region where

climatic conditions allow standing water

There must be some process

that forms a basin

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Inlandwaters

cover

less than

2% of

Earths

surface

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Most of the worlds fresh water occurs in

about 20 extremely deep lakes (> 400 m)

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Morphometrythe size and shape of a lake

basin. It reflects a lakes mode of origin. It is

best described by a bathymetric map.

Basin morphometry has a strong effect on

nearly all physical, chemical and biologicalprocesses

2nd lab will focus on many basic

morphometric parameters

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Introduction to Bathymetric Maps

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Hutchinson (1957)

details 76 types of lakes

We will cut it down to

10 (plus subcategories)

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Depressions formed by movements of deeper portions

of the Earths crust.

THERE ARE 2 MAIN TYPES

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Type 1: Uplifted areas of Earths crust

Lake Okeechobee, FL

Surface Area =1,800 km2

Depth = 3 m

2nd largest surface area

completely within the US(Lake Michigan is 1st)

www.evergladesvillage.net/ sat/everglades/

http://www.sfwmd.gov/org/wrp/wrp_okee/images/jpgs/okee_ag.jpg
http://www.evergladesvillage.net/sat/everglades/http://www.evergladesvillage.net/sat/everglades/

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Downfaulted troughcalled a

graben

Very deep, very steep sided

lakes

Long and narrow

Type 2: Faults

These are some of the deepest, oldest lakes in the world

Single fault displacement

Often associated with mountain rages

Long and narrow

2 Types of fault-formed basins

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Examples of grabens

Lake Baikal,

Siberia

20% of Earths fresh water

(deepest lake in the world)

25 million years old

www-geoazur.unice.fr/PERSO/calais/ CEO/618440/baikal_h.gif

malawidrilling.syr.edu/ images/ri12.jpg

Surface Area = 31,500 km2

zmax=1,741 m

www.eawag.ch/.../UI/baikal/results/ helium/figures/He.1.GIF

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Lake Tahoe, California-Nevada

https://reader009.{domain}/reader009/html5/0427/5ae20b1b25f6c/5ae20b2377234.jpg

http://www.ilec.or.jp/database/nam/NAM02-01.gif

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African Great Lakes

UpliftLake Victoria

FaultLake Tanganyika

Lake Malawi

Tanganyika

zmax

= 1,435 m

Other rift lakes

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Basins created in volcanic regions


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Type1: Caldera lake formed in cone of extinct volcano

Crater Lake, OR

http://www.bmsc.washington.edu/people/verlinde/pics/crater-lake.gif

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Type 2: Maar crater of explosive origin. Result from

magma coming into contact with ground water.

Nearly circular, but can be quite deep (>100m)

www.geomar.de/~abelouso/ maar.html
http://www.geomar.de/~abelouso/maar.htmlhttp://www.geomar.de/~abelouso/maar.html

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Type 3: Valleys dammed by lavahttp://www.frantzen.de/nz/north/S_139-lake-rotoaira.JPG

Lake Rotoaira, New

Zealand

Lake Bunyoni, Ugandahttp://images.google.com/imgres?imgurl=www.visituganda.com/places/lakeBunyoni.jpg&imgrefurl=http://www.visituganda.com/places/lakesislands.htm&h=162&w=241&prev=/images%3Fq%3DBunyoni%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8

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Can form fairly large lakes, but are often temporary because the dam erodes

Lakes created by recent movement of debrishttp://earthobservatory.nasa.gov/Newsroom/NewImages/Images/ISS002-ESC-7771_lrg.jpg

Lake Sarez, Tajikistan

Created in 1911 when a

strong earthquake

triggered a massive

landslide, now called the

Usoi Dam.

Zmax = 500 m

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Basins created by the movement of ice sheets


3 from existing glaciers

3 from past glaciers

L k f d b i ti l i

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Lakes formed by existing glaciers(Greenland, Antarctica, Mountains)

Type 1: Lakes can form

on the surface of

glaciers. They are small

and shallow.

Type 2: Lakes can form

when either the glacier

or the moraine forms

a dam

http://crevassezone.org/Photos/Graphics/4401L-(Lemon-Lakes).jpg

Hutchinson 1957

T 3 S b l i l l k

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Type 3: Subglacial lakes.Lakes formed beneath

glaciers in basins scoured

by glacial activity

More than 70 such

lakes found in

Antarctica.

One of the largest

and most famous is

Lake Vostok

http://www.ldeo.columbia.edu/~mstuding/vostok.html

Analog for Europa (a moon

of Jupiter)?

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Lakes formed by past glaciers

Type 4: cirque lake. These occur when the glaciercarves out an amphitheater-like area up in the mountains

http://crevassezone.org/Photos/Graphics/4163L-(Cirque).jpg

http://www.ship.edu/~cjwolt/geology/slides/jpg/gllab04.jpg

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Finger Lakes, NY

Type 5: lakes formed by morainal damming.

http://www.visitithaca.com/images/Ithaca-aerial.jpg

tapestry.usgs.gov/ features/42fingerlakes.html

T pe 6 kettle lakes These lakes
http://tapestry.usgs.gov/features/42fingerlakes.htmlhttp://tapestry.usgs.gov/features/42fingerlakes.html

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Type 6: kettle lakes. These lakeswere formed when an ice block

was caught in glacial drift or

outwash.

It may have taken several

hundred years to melt

completely.

Many relatively small

lakes of irregular shape

Typically less than 50 m

deep

Kettle ponds are 1 -2 m

deep

Wetzel 2001

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Common in Florida, Michigan, Indiana, Kentucky and

Tennessee, Mexico

Regions of the Adriatic, Balkan Peninsula and the Alps

Also in Caves

Lakes created through a chemical reaction

between water and limestone

(also called sinkhole lakes)

Most often in regions of limestone (CaCO3) where there

is slightly acidic ground water (CO2)

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a. Plunge pool formed at the base of former

waterfalls. Very specific shape to the basin

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b. Oxbow ponds formed when a river meanders

and eventually cuts off a bend

Kalff 2002

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http://www.gac.edu/oncampus/academics/geography/MISS.JPG

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These aresometimes call

deflationbasins or

playas. Oftenfound in arid

regions and

are temporary

Shallow lakes in arid regions formed bywind erosion

espn.go.com/.../ s/2003/0708/1578239.html
http://espn.go.com/outdoors/conservation/s/2003/0708/1578239.htmlhttp://espn.go.com/outdoors/conservation/s/2003/0708/1578239.html

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When the ocean or a large lake has an irregular shoreline, a bar may

develop and cut off the new, smaller lake.

Lakes formed in close proximity to theshoreline of a large lake or ocean

http://www.csc.noaa.gov/techniques/recreation/images/ontario1.jpg

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Basins formed when people oranimals create them http://www.noeckerbuickpontiac.com/DAM-78.jpg

Reservoirs formed for recreation barge traffic

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Reservoirsformed for recreation, barge traffic,

cooling for power plants, water control, hydroelectric

power

Characteristic shape, dam at one end

Richland Co., IL

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Borrow pits and old strip mines

Vermilion Co., IL

Champaign, IL

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Rare, but spectacular

Hutchison1967

Chubb Lake, Quebec

Zm = 251 m

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Laurentian Great

LakesIce scour

(glacial) followed by

rebound of Earths crust(tectonic).

Largest continuous

mass of fresh wateronEarth (24,620 km3)

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Lakes of Unknown Origin

Carolina Bays Found mostly in the Carolinas, but all over

south east US. Up to 500,000 small, oval basin going mostly

northwest-southeast. Some say they were formed in a meteor

shower, others say they are deflation basinshttp://images.google.com/imgres?imgurl=www.georgehoward.net/images/ccbay1.jpg&imgrefurl=http://www.georgehoward.net/cbays.htm&h=319&w=300&prev=/images%3Fq%3DCarolina%2BBay%26start%3D80%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26sa%3DN

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Why is it important to know howa lake was created?

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3. Ground water, either as seepage or as springs

To have a permanent lake, inflows must exceed outflows

Inflows

1. Runoff from the drainage basin (watershed)

2. Direct precipitation

The size of the lake determines which of these is most important

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2. Evaporation and evapotranspiration (water transported

up through vegetation and lost through the leaves).

Evapotranspiration is very important in temporary ponds

Outflows

1. At the effluent, which is the lowest point on the rim. Some

lakes are just wide and deep spots in the stream or river.

3. Seepage through the floor of the lake

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Obviously, the relative importance of the

three outflows depends on whether a lake

is an open or closed basin.

If a lake has an open basin,it means it has an effluent

If a lake has a closed basinit means it

does not have an effluent

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do you find lakes?

The location of standing water on

Earth is influenced by global weather

patterns.

Water evaporates from the oceans,

and is returned to the land via rain,

snow, sleet, hail, dewbut not evenly

Already talked about where you find basins

Kalff 2002

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Processes such as

trade winds, El Nio

Southern Oscillation

and North AtlanticOscillation affect

where the precipitation

falls

Global weatherpatterns are also

influenced by

local geography

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There must be some

process that forms a

basin

The climate mustallow standing

water

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morphometrybathymetric

graben

caldera

maarmoraine

cirque

subglacial

kettle

sinkhole

plunge pooloxbow

deflation basin

playa

reservoirborrow pit

Carolina Bay

effluent

evapotranspiration

open basin

closed basin

Important Lake Names:

African Great Lakes

Malawi

TanganyikaVictoria

Baikal

Chubb Lake

Crater Lake

Finger LakesLaurentian Great Lakes

Huron

Ontario

Michigan

ErieSuperior

Tahoe

Okeechobee

Vostok

Terms to Know

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