Cycles of the Earth
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Hydrological Cycle and Weather
Climate
Chemical Cycles
Ice Ages
Rock Cycle
Geological Time Scale
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
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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 (18371840)
Svante August Arrenius
• Developed theory of
Greenhouse Effect to
explain Ice Ages
• 1896 calculated how
changes in CO2
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 19th Century
1821-1890; Britain (Scotland)
Milutin Milanković
• Canon of the Earth’s
Insolation: climates
of the planets
• 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 22.1o to
24.5o )
• 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
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Magma
Crystallization (freezing)
Igneous rock
Erosion
Sedimentation
Sediments & sedimentary rock
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
Arthur Holmes
• Pioneer of radiometric
dating (Uranium-Lead
method). Wrote this in a
book by the time he was 24.
• Provides absolute time to
strata
• Showed the earth was more
than 1 BY old (most
geologists had accepted that
the earth was only 100 MY
old)
• Completed the Geological
Time Scale in 1944
1890-1965; England
Geological Time Scale