Salahaddin University-Erbil
College of Science
Geology Department
Geotectonics-Practical
4th Class-Geology
Second Term
2018-2019 Academic Year
Geotectonic
Scientific Inquiry
Lab No. 1
Scientific Inquiry
• Gather data
• Formulate plausible
explanations
• Devise tests and predictions
• Revise, reject or accept
explanations
Hypothesis vs. Theory
Hypothesis is an explanation that
requires testing
Theory has been tested, and is supported
by the evidence, and predicts things not
used to formulate the hypothesis
The Universe
Big Bang forms all matter
The Universe
Nebular Hypothesis
• Formed our solar system
– Sun
– Planets
– Asteroids and comets
• Rotating cloud of dust and gases
collapses into these bodies
Nebular Hypothesis of Solar System
Formation.
Celestial Motion
Brief Review
• Sun is at the center of the solar system
• Published by Copernicus
– Supported by Galileo’s telescopic
observations of Jupiter and Venus
• Kepler determined orbits are ellipses
• Newton determined orbits created by
interaction of inertia and gravity
The Universe
Orbital motion of planets
Earth Movement
• Rotation on axis
• Revolution (orbit) around Sun
• The average distance between Earth
and the Sun is 149.60 million km and
one complete orbit takes 365.256 days
(1 sidereal year)
What is a ‘day’?
• Mean Solar Day
What is a ‘day’?
• Sidereal Day
What is a ‘day’?
• Mean Solar Day—24 hours
• Sidereal Day—23 hours, 56 minutes
Celestial sphere
Axis of rotation
Moon
• 3475 km diameter
• Density ~ Earth’s mantle
Moon’s Motion
• Rotates on axis once each 27 1/3 days
• Same side always faces Earth
• No atmosphere—extreme temperature
variation: 127o to -173o C
• Distance from the Earth 384,400km
Moon’s Motion
Moon’s Motion
Moon’s Motion
Solar Eclipses
Meteorite impact
Meteorite impact
Earth’s Interior Layers
Earth Structure, 2004
Earth’s Interior Layers
Composition
Rheology
(Seismic Velocity)
Crust
Lithosphere
Mantle
Asthenosphere
Earth Structure, 2004
Earth plates
Plate Motions
Frisch, 2011