Cycles of the Earth

heehawultraMechanics

Feb 22, 2014 (3 years and 5 months ago)

68 views

Cycles of the Earth

Hydrological Cycle

Taxonomy of Clouds

Luke Howard (1772
-
1864),
Britain

Fitzroy and the Weather Forecast


In the British Navy and
responsible for weather
reports


Coined phrase Weather
Forecast


Convinced that
barometer readings
foretell tomorrow’s
weather


Committed suicide after
he was ridiculed by the
press and the Admiralty
dropped the need for
forecasting

Vice
-
Admiral Robert Fitzroy
(1805
-
1865), Britain

High and Low Pressure

Cyclonic
Circulation

Collision of Air Masses

Ocean Currents

Movement of the Air

Hadley cell named for George Hadley (1685
-
1768) tried to explain why trade winds seemed
to flow to the west

Climate Conveyor

Global Climates

El Niño & Gilbert
Thomas Walker

1868
-
1958; England & India

Chemical Cycle: Carbon

Chemical Cycle: Oxygen

Chemical Cycle: Nitrogen

Ice Ages

Evidence of Glacial Action


Moraines


Glacial Till and Flour


Erratics


U
-
Shaped Valleys

Jean
Louis

Rodolphe

Agassiz
(1807
-
1873); Switzerland and
USA

Proposed Europe had been
subjected to an Ice Age (1837
-
1840)

Svante

August
Arrenius


Developed theory of
Greenhouse Effect to
explain Ice Ages


1896 calculated how
changes in CO
2

concentration could
change climates

1859
-
1927; Sweden

James
Croll


Used the formulas
developed by Le
Verrier

on
planetary orbital variations


Developed a theory about
orbital variations influencing
the amount of snow


Orbital eccentricity should
cause ice ages on a 22,000
year cycle


Largely dismissed by end of
the 19
th

Century

1821
-
1890; Britain (Scotland)

Milutin

Milanković


Cannon of the
Earth’s Insolation


Explanation of
changes in Earth’s
climate by
interactions of three
planetary cycles

1879
-
1958 (a Serb) born
in Kingdom of Hungary
and died in Yugoslavia

Milanković

Cycles


Eccentricity of earth’s
orbit (
Kepler’s

theory)
has a 100,000 year
cycle from 0.005
(nearly circular) to
0.058 (mildly
eliptical
)


Axial tilt has a 41,000
year cycle (tilt
changing from 22.1
o

to
24.5
o

)


Precession has a
23,000 year cycle
(suggested by
Hipparchus in 130
BCE)

Inference of Climate Based on
Temperature Proxies

Pollen

Tree rings

Ice cores

Ratio of oxygen isotopes

Corals

Diatoms and foraminifera


Rock Cycle

1.
Magma

2.
Crystallization (freezing)

3.
Igneous rock

4.
Erosion

5.
Sedimentation

6.
Sediments & sedimentary rock

7.
Tectonic burial and
metamorphism

8.
Metamorphic rock

9.
Melting

Defined by Hutton and Lyell and modified by John
Tuzo

Wilson

(1908
-
1993), Canada.

His Ph.D. advisor: Harry Hess

Rock cycle explained by erosion and action of plate tectonics

Using Steno’s Laws, attempt to
interpret geological strata by
relative time

Jean Léopold Nicolas
Frédéric

Cuvier

&
Alexandre
Brongniart


Together studied geology of Paris basin


Defined concept of faunal succession


Theory of cycle of repeated catastrophes

Cuvier

(1769
-
1832)
France

Brongniart

(1770
-
1847)

France

William ‘Strata’ Smith


Surveyor


Strata of coal
mines and canals


Used principle of
faunal succession
to define layers


Life’s work:
Geological map of
England and
Wales

1769
-
1839, England

A plate of Smith’s
fossils

Roderick
Impey

Murchison, 1st Baronet



Independently
wealthy, urged by
Humphry

Davy to turn
his focus to science


Became interested in
the geology of Wales,
England, Alps, Russia,
Scotland


Helped define the
Silurian, Devonian, and
Permian Systems

1792
-
1871, Britain (Scotland)

Adam Sedgwick


Cambridge University
faculty (ordained in the
Church of England)


Defined Cambrian system


Worked with Murchison
to define Devonian in
England and on the
system in the Alps


Charles Darwin was his
student who helped to
define the sequence of
Cambrian rocks in Wales

1785
-
1873, England

Radiometric dating provides
absolute time to strata

Geological Time Scale