The scientific method and the foundations of Geology

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The scientific method and the foundations of
Geology
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Goals

• To understand the basic scientific method as it
  applies to the Earth Sciences
• To cover some of the basic principals of the
  Earth Sciences

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Question?
Siccar Point, Scotland
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The Scientific Method

• QUESTION We want to know how some part of the
  Earth works.
• DATA COLLECTION Observe, measure, describe,
  compile.
• HYPOTHESIS A logical but tentative explanation
  that fits all the data collected and is expected
  to account for future observations.

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Its not just a theory

• TESTING Testing, testing, and more testing.
• MODIFICATION Hypotheses are modified to include
  the results of testing (see 4).
• THEORY Our hypothesis now withstands rigor of
  all the testing (see 4) and consistently
  explains accumulating data.
• It is now a theory A generally accepted
  explanation for a large set of diverse data and
  observations.

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If a theory is really special...

• TESTING Testing, testing, and more testing.
• SCIENTIFIC LAW If a theory meets rigorous
  testing over a long period of time it may become
  a Scientific Law, like The Law of Gravity.
• PRINCIPAL Generally a scientific law is so
  fundamental it provides the foundation of science.

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How we develop and test hypotheses in the Earth
Sciences

• Because we cant fit the Earth in a test tube or
  sit and take notes for 20 m.y we use
• Case studies of ancient features
• Remote sensing of the Earths interior
• Numerical and analogue simulations

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We have learned that the Earth is very old (4.5
billion years). So. We have lots and lots and
lots of time to work with.
The present is the key to the past
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Birth of modern Geology

• Principle of Uniformitarianism Processes
  observed today have acted on the Earth over very
  long periods of time.
• So
• Observations of current geological processes can
  be used to interpret very old geologic events.

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Other Important Geologic Principles

• Superposition In any unaltered sequence of rock
  layers, each layer is younger than the one
  beneath it and older than the one above it.

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Other Important Geologic Principles

• Superposition In any unaltered sequence of rock
  layers, each layer is younger than the one
  beneath it and older than the one above it.

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• Original Horizontality Sediments are deposited
  horizontally in layers that are parallel or
  nearly parallel with the Earths surface.

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Think-pair-share activity

1. Come up with an every day analogue for the
   principal of original horizontality (preferably
   incorporating unhealthy food).
2. Compare, discuss, and refine your analogue with
   one or two of your neighbors.
3. Write up your results and pass them in.

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• Cross-Cutting Relationships An igneous intrusion
  or geologic structure is always younger than the
  rock that surrounds it.

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Answer
Siccar Point, Scotland
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1. Deposition
2. Tilting
3. Erosion
4. Deposition
5. Tilting
6. Erosion

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• Principle of Inclusion Rock fragments contained
  within a larger body of rock are always older
  than the surrounding body of rock.

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Basic rock types

• Igneous rocks Crystallize (or freeze) from a
  melt
• Sedimentary rocks Made up of particles (gravel,
  sand, clay) glued and pressed together
• Metamorphic rocks Rocks that have recrystallized
  at high temperatures and pressures, but not
  melted.

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The rock cycle