The course will be a presentation of plate tectonics and the physical
processes currently shaping the Earth, using the "Ring of Fire," a narrow
band of recurring earthquakes and volcanoes that rings the Pacific Ocean,
as a focus. It will describe the current state of knowledge about the
geology of our planet, showing how the concept of plate tectonics explains
the existence of many diverse things, from earthquakes and volcanoes to the
formation of mountains and oceans to the diversity of life and past
extinctions of animals.
We will begin with the current theories first of the creation and age of
the universe and then the formation of our solar system and earth. We will
use evidence from the fossil record and the geological structure of the
continents to discern the manner in which the planet has cooled down since
its molten accretion 4.55 billion years ago.
The current state of the earth will then be closely examined from many
different perspectives. We will see how mountains are constantly being
pushed up, only to be torn down by the erosional forces of wind, rain,
rivers and glaciers; the earth's magnetic field reverses direction at
irregular time intervals; earthquakes and volcanoes occur only in very
particular areas, and usually in long, narrow zones; and the patterns of
seismic waves from large earthquakes and the different values of the force
of gravity at the Earth's surface, as measured by satellites, give us
information about the structure of the inside of our planet. Other clues
such as the formation of diamonds and the patterns of Pacific Islands will
also give us information as to the larger picture of the earth's activities.
Once all pieces of the puzzle have been examined, we will put them together
in the framework of plate tectonics. We will see how the earth's surface is
broken into plates which move relative to each other. Some move apart, such
as the North American and European plates, causing huge rifts where molten
lava rises to fill the cracks. Others collide like the Pacific and Asian
plates, causing one plate to subduct under the other. This results in large
numbers of earthquakes and volcanoes, as in Japan, or the creation of
mountains, as in the case of the ever growing Himalayas, which result from
the collision of the Indian and Asian plates. Other plates slide past each
other and cause large earthquakes along long faults, as in the case of the
San Andreas Fault between the Pacific and North American plates.
The course will explore the historical record of plate tectonics, such as
the formation of the great ancient land mass called Pangaea and the huge
extinction of many life forms which may have resulted from its
break-up. Evidence of these motions comes from many sources, ranging from
the shapes of the continents to the geology of the rocks in the continents
and ocean floors (for example, Most of Nova Scotia (and part of Rhode
Island!) used to be African rock which broke off when the Atlantic Ocean
began forming). Finally, the mechanism by which plate tectonics works,
answering the question, "what drives the plates?" will be discussed, using
the Pacific plate (with its active boundaries stretching from the Andes
Mountains in Chile to the volcanoes of Alaska and Japan to the earthquakes
under Tonga and Fiji) as a case study.
Text: Geology, 4th Edition, by Chernicoff and Whitney (required).
There will be
A list of questions (from which the final exam questions will be chosen) will be handed out at the end of class (and posted on the web site). Passing for Pass/Fail options is a C- or better.
- two short (5-page) papers,
- one short in-class presentation,
- some on-line assignments, and
- a final exam.