Download Pieces of a Puzzle

Pieces of a Puzzle
O Law
O Tells you exactly what to expect in certain situations
O Newton’s Laws of Motion
O Theory
O An explanation that ties together many hypotheses
and observations.
O It is based on scientific evidence.
Theory of Continental Drift
O ***add to comparing and contrasting foldable**
O Proposed by Alfred Wegener in 1915
O He suggested that the continents were once
joined together as one “supercontinent.”
The Theory of Plate Tectonics
•
the Earth’s lithosphere is divided into tectonic
plates that move around on top of the
asthenosphere
•
continents move at a rate of 2cm per year or
about 1 inch year
Comparing the Theories
(“Both” on the foldable)
O Continents move
O Earth was once made up of one large continent
O Same evidence proves the theories
O fossils
O puzzle pieces
O glacial deposits
O mountain ranges
• Pangaea “all land”
– The name of the one supercontinent
– All continents joined together as one large land
mass
http://www.youtube.com/watch?v=q_IYQdKkWs
U
O Alfred Wegener
O His studies were the 1st exhaustive research on the
topic
O He compiled evidence from many disciplines
O His theory/hypothesis was not accepted by many
scientists
O What? – Theory of Plate Tectonics
O It did not seem possible that the crust could move in
that way
O Finally accepted with discovery of sea floor spreading
in the 1960s
O When?
O 245 mil yrs ago: Pangaea
O 180 mil yrs ago: Laurasia & Gondwana
O 65 mil yrs ago: continents continue to separate
O 1620: Alfred Bacon – puzzle
O 1858: Snider-Pellegrini - fossils
O 1910: Frank Taylor - geological
O 1915: Wegener – put it all together
O 1960: seafloor spreading
O Where?
O continents and oceans
O lithosphere and asthenosphere
O Evidence of Continental Drift
O Shapes of continents and the way they appear to
fit together like pieces of a puzzle
O Similar rock structures found on different
continents
O (highlight: locations of different types and ages of
rock)
More Evidence of Continental Drift
O Fossils found on different continents
O (highlight: matching fossil remains)
O Glacial till deposits of same age and type
found on different continents
O (highlight: glacial deposits)
O Matching mountain belts located on different
continents
O (highlight: matching mountain belts)