Transcript Great Theorists of the Earth (2)

James Hutton, 1785: The Theory of the Earth
An Earth “with no vestige of a beginning and no
prospect for an end…”
1)
2)
3)
4)
Earth History is Cyclical
Earth Processes are Gradual
The Earth is Infinitely Old
The Interior of the Earth is Hot – the Earth is a
Fiery Machine
5) Most Rocks are Igneous
6) Basalt is an Igneous Rock
William Smith and George Cuvier - 1790’s
Smith: British Mining Engineer, Economic
geologist.
Cuvier – Europe’s greatest anatomist (Swiss),
studied functional morphology and extinction.
1) Once a species disappears it never
again reappears.
2) No two species are identical.
These observations led to the following
two principles:
1) The Law of faunal Succession – In the geologic
record, fossil faunas succeed on another in an
orderly and determinable fashion. Therefore,
rocks of different ages have different fossil faunas.
2) The Principle of Fossil Correlation – Similar
assemblages of fossils are similar ages, and thus
the rocks that contain them are of similar ages.
Fig. 2.10
Napoleon’s
profile
FOSSIL
SUCCESSION
Fossil Correlation
Smith’s Geologic Map
Modern Geologic Map
Based on studies of fossil elephants & giant sloths,
Cuvier recognized that organisms have become extinct.
This was highly controversial!
Mass
Extinctions
Cuvier noted that Earth upheavals (like mountain
building events) were often accompanied by mass
extinctions. Thus, the extinction of millions of
organisms by violent Earth changes became known as
Catastrophism. It was based on direct observation of
the fossil record.
•Earth history was beset by violent upheavals that
periodically wiped out nearly all organisms.
•God then created a new fauna to replace the extinct
one.
•All this happened within Buffon’s age of 75,000 years.
Buffon claimed, “ A year is to God as a thousand years
is to man”.
The History
of Life
In the 1820’s London begins to replace Paris as the center of
geological research. The response to Catastrophism came from
another gentleman Scotsman named Charles Lyell
Lyell was an Oxford student of a famous geologist/clergyman, the
Reverend William Buckland (1784-1856), Dean of Westminster
William Buckland
“The gentleman geologist”
Evidence for Buckland’s Diluvial Theory:
1) Fossils of extinct species of hyenas are preserved
in ancient cave deposits. A product of flooded hyena
dens in caves.
2) Earth’s last convulsion and extinction was
Universal and caused by Noah’s Flood.
These deposits are generally confined to the northern parts
Of the northern hemisphere. What caused them?
Mollusc
Borings
Temple of Serapis, near Naples, Italy
Lyell’s Uniformity: An idealized cross section of the Earth
showing ancient and modern rocks being formed by the same
processes.
Lyell’s Uniformitarianism
A) Methodological - Basis of Science
1) Uniformity of Law
2) Uniformity of Process – Actualism
B) Substantiative – Testable by Observation
3) Uniformity of Rate (Gradualism)
4) Uniformity of Condition (non Progressionism)
"huge Iguanodon might reappear in the woods, and the ichthyosaurs in the sea,
while pterodactyle might flit again through umbrageous groves of tree ferns.“
Charles Lyell, 1833
Professor Ichthyosaurus, at some future time after his triumphant return,
lecturing to his students on the fossil skull of a peculiar Quaternary mammal.
By Henry de la Beche, from Buckland, 1890.
Tertiary
Lyell Subdivided a major Geologic
Period based on mollusc faunas
Succession of Rocks and faunas
demonstrated antiquity of Earth