1 Geology 1001/1101 Sec 003 Chris Paola Class 12: climate and glaciation.

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Geology 1001/1101

Sec 003 Chris PaolaClass 12: climate and glaciation

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Chapter 10

THE CLIMATE SYSTEM

AND GLACIATION

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Key ideas about climate & glaciation

• Much of Minnesota’s landscape has been sculpted by glaciers

• Glacial cycles are controlled by variation in Earth’s orbit on time scales of 10,000 – 100,000 yr

• Climate weather; climate is long-term average of weather

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Climate: planetary controls

• Distance from Sun

• Albedo (reflectivity or “whiteness”)

• Atmosphere (greenhouse effect)

• Orbital properties

• Plate configuration (mainly due to effect on ocean circulation)

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Climate: geographic controls

• Distance from equator

• Average air flow & pressure

• Distance to the ocean

• Prevailing wind relative to mountains & ocean

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Hot

Cold

NOT distance to Sun!

3,900 miles

92,900,000 miles

7all sunlight that hits Earth’s surface

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10% of sunlight spread across 6.5% of sunlit surface

at equator, Earth’s surface is almost perpendicular to sunlight, so energy is concentrated in small area

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~ 150% of average intensity

at equator, Earth’s surface is almost perpendicular to sunlight, so energy is concentrated in small area

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at poles, Earth’s surface slopes away from sunlight, so energy is spread across a greater area

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< 50% of average intensity

at poles, Earth’s surface slopes away from sunlight, so energy is spread across a greater area

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Hot

Cold

due to the angle of the Earth’s surface

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Global air flow determines large-scale rainfall patterns

Mars: one cell perhemisphere

14Earth: 3 cells perhemisphere

wet

dry

dry

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Jordan, The Essential Earth 1e © 2008 by W. H. Freeman and Company


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Energy and power

• Energy (work) – Joules– BTUs: 1 BTU = 1055 J– Kilowatt-hour: 1 KWH = 3600000 J– Calorie (food): 1 Cal = 4187 J

• Power: energy per time (energy rate)– 1 Joule/sec = 1 Watt– 1 HP = 746 Watt

• US energy consumption (power), per capita: 11.4 kW (11,400 Watt)



99%

of

air

mas

s

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Importance of the ocean in climate

• Heat storage (heat capacity of water >> that of air)

• Heat and moisture transport


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Ocean currents

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Importance of the ocean in climate

• Heat storage (heat capacity of water >> that of air)

• Heat and moisture transport

now onto the cryosphere…






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A side note: Ice and sea level




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El NiñoWarm, rising air here lo pressure helps maintain the wind pattern

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El Niño movie

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Part II: glaciation



Movies


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Minnesota in the ice age

Thanks to MN State U

http://mrbdc.mnsu.edu/mnbasin/fact_sheets/graphics/glaciers/us_glacier.gif

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http://mrbdc.mnsu.edu/mnbasin/fact_sheets/graphics/glaciers/glacier_2.gif

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Minnesota glacial features


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Satellite image

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Thanks to geologyclass.org

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Moraine map, S Minnesota

Big Stone Moraine, Traverse Cty

End moraine, Freeborn Cty

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Superior Lobe till, central MN, thanks to Karen Kleinspehn

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Drumlin

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Minnesota* glacial features

Drumlins

*OK, Saskatchewan

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Drumlin field near Green Bay

*OK, Wisconsin

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Drumlin?

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Esker, Oakwood Lake

*OK, S. Dakota

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Esker

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Esker, Finlayson MN

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Esker

*OK, Wisconsin

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Speaking of glaciers and volcanoes…

Word of the day: jokulhlaup

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Jokulhlaup

Former bridge

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Our own version…

Montana/Idaho glacial lakes

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Channeled scablands

Eastern WA


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Evidence for a similar flood in the English channel

(S. Gupta, Imperial College London)

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Longer history and causes of glaciation



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favors glaciation

100 kyr

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Lower solar intensity in NH

41 kyr

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NH summer when Earth farthest from Sun

NH winter when Earth farthest from Sun: favors glaciation

23 kyr


1 Geology 1001/1101 Sec 003 Chris Paola Class 12: climate and glaciation.

Documents

glaciation slide

watt slide

hemisphere slide

cryosphere slide

earths surface slide

mountains ocean slide

ocean circulation slide

air mass slide