Transcript A new Paradigm… Plate Tectonics

Plate Tectonics
and the Ocean
Floor
© 2011 Pearson Education,
Inc.
Which is Which?
Continental Drift
► In
1912 Alfred Wegener proposed that
millions of years ago all of the continents
were part of one supercontinent called
Pangaea.
Evidence for Continental Drift
► Wegener
proposed
Pangaea – one large
continent existed
200 million years ago
► Panthalassa – one large
ocean
► Noted puzzle-like fit of
modern continents
Evidence for Continental Drift
► Matching
sequences
of rocks and
mountain chains
► Similar rocks on
different continents
Evidence for Continental Drift
► Same
fossils found on continents that today
are widely separated
© 2011 Pearson Education,
Inc.
► At
first the hypothesis of Continental Drift
was not accepted.
► Now,
widely accepted, it has become
incorporated into the Theory of Plate
Tectonics.
Continental Drift
► https://www.youtube.com/watch?v=_5q8hz
F9VVE
Theory of Plate Tectonics
► Lithosphere
– tectonic plates that float on ductile
asthenosphere
► Large scale geologic features occur at plate
boundaries
► An
early Theory?
► https://www.youtube.com/watch?v=Hf74Sp0Xe6
Q&feature
Plate Tectonics: A new way of
thinking
► Paradigm
Shift: Change in world view
 Shape of the Earth
 Continental drift
 Sustainability (?)
► The
theory of Plate Tectonics caused a
Paradigm shift in how the Earth moves and
how new crust is created.
Marie Tharp
► Mapped
the Ocean floor.
► In
1952 she identified a key feature of the
ridge dividing the North Atlantic. This was a
controversial assertion during the decadeslong debate over continental drift.
► By
the time Marie retired in 1983, plate
tectonics had been widely accepted; she
had witnessed, and help to foster, a
complete transformation of her field.
Plate Tectonic Processes
Plate Tectonics
► https://www.youtube.com/watch?v=ZTRu62
0bIsE
A Little Lesson on
Longitude and Latitude
Latitude & Longitude
► Latitude
is distance north or south of the Equator
and longitude is distance east or west of the prime
meridian.
►
Both are measured in terms of the 360 degrees
(symbolized by °) of a circle. Imaginary lines of
latitude and longitude intersect each other,
forming a grid that covers the Earth and helps us
locate points on it.
Latitude
►
►
►
The Equator is the line of
0° latitude, the starting
point for measuring
latitude.
The latitude of the North
Pole is 90° N, and that of
the South Pole is 90° S.
The latitude of every point
in between must be some
degree north or south,
from 0° to 90°.
Longitude
► The
line which runs through Greenwich in
London is called the Greenwich Meridian or
Prime Meridian.
► The Prime Meridian is 0° longitude.
•The Earth is then divided into 180°east and
180°west.
•The International Date Line lies at
180°east/west
Longitude & Latitude Assignment
► Complete
the Longitude & Latitude
Assignment.
► Due
to be passed in:
 Wednesday September 9th