Earth Systems 3209
Unit 2: Historical Geography
(14 classes)
Unit 2 Outline
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Uniformatarianism Vs. Catastrophism
Relative Vs. Absolute time
Core Lab 1: Interpreting geologic events
Absolute Dating
Unit 2 STSE: Absolute Dating
CBC Doc: Canadian shield
Unit 2 Quiz
Fossils
Core Lab 2: Estimating Dinosaur size
Geologic time scale
Unit 2 Test
Question!
• Where these mountains (Himalayan) formed
quickly or slowly? Why?
Question!
• Did the dinosaurs mass extinction happen
quickly or slowly? Why?
So do Geologic events happen Quickly?
or Slowly?
Catastrophism
• Is a concept popular in the 1700-1800’s which states
that earth’s landscapes had been shaped primarily by
great disasters or catastrophes
(floods, storms, earthquakes, volcanic eruptions etc.)
• James Ussher: Anglican Arch Bishop
and scholar attempted to fit the rate of
change of Earth processes into a relatively
young aged Earth.
** Unknown causes which were fast
James Hutton
• Scottish Geologist after years of studying
landforms and rocks
• “ the present is the key to the past” and
• “that, the physical, chemical,
biological laws that operate
today to shape Earth also
operated in the past.”
Uniformitarianism
• two key concepts;
1) the geologic processes at work today were
also active in the past.
2) the present physical features of Earth were
formed by these same processes, at work
• over long periods of time.
So is one right and one wrong?
• Not necessarily, some geologic events can be
explained by catastrophes, wile other through
uniformitarianism
Question!
• How would the ideas of Catastrophism and
Uniformitarianism explain the formation of
the Hymalayas?
Dating geologic events
how old are you?
• Quantitative measurements: describing
something using numbers
• how old are you? (use quantitative)
• Example: He is 14.5 years old
how old are you?
• Qualitative measurments: Describing
something using words.
• Can you describe your age without using any
numbers at all? How?
Absolute time
• Identifies the actual date of an event, &
pinpoints the exact time in history when
something took place.
• For example, the extinction of the dinosaurs
about 66 million years ago and the age of
• Earth is approximately 4.6 Billion years.
. Relative time
• Attempts to place events in a sequence of
formation, but does not identify their actual
date of occurrence.
• Comparing events to each other often does
this.
• Can’t tell us how long ago something
happened; only that it followed one event and
preceded another.
Work in groups
• answer questions on Handout