G102/203 Name__________________________________
Out of class assignment Due: 5-18-09 (MWclass)
or 5-19-09(TTH class)
This worksheet can be found
on the class web page if you want to load it into word and type your responses.
Words to define: Use the glossary in the book to define the following
words. Those words not found in the
glossary have a page number reference in your text for you to find them.
Pillow Lavas
Granite (pg 99 text)
Gneiss (pg 185 text):
Banded Iron Formation:
Ophiolite
Now, read pages 532-539
and answer the following questions.
1) What part of geologic time is represented by
the Hadean?
2) Based on your reading, why do geologists
believe there was crust during the Hadean even if we can’t find rocks dating to
that time?
One of the theories discussed
in the book for the formation of the continents is based on the the concept of partial melting. A bit of background is in order. Remember, rocks are made up of minerals. Different combinations of minerals make
different rock types. Continental crust have minerals rich in silica while mantle rocks are
made of minerals that are low in silica.
Oceanic crust falls somewhere between them. Minerals rich in silica melt at lower
temperatures while minerals low in silica melt at high temperatures. In nature, when a rock begins to melt,
usually only part of the rock will melt…not all of it. As a result, the parts that melt are those
minerals that are higher in silica. This
means that the melt created is richer in silica than the rock it came
from. Use this idea and answer the
following question.
4) Based on your
reading, explain how the idea of partial melting relates to the evolution of
continental crust?
5) What is the craton
or shield of a continent?
6) Where are the oldest cratons
found and what are their ages?
7) What amount of geologic time is represented by the Archean ?
8) What are the greenstone belts and what are they
made up of?
9) How was plate tectonics different in the archean than it is today and why
was it different?
10) How much of the earth’s present continental
crust existed at the end of the archean?
For the rest of this exercise
go to the following web page (there is a link on the class web site) follow the
directions below and answer the following questions http://www.scotese.com/
Click on the Earth’s history
button on the right side of the page
Scroll through the geotimes
in order (from top to bottom) and read the captions below each map. In the upper left corner of each page is a
button for more information if you want to explore a bit more.
11) During the Precambrian what was the name of
the super continent that formed?
For this page, click on the
more information button to answer the following questions:
a)
In YOUR words, explain why it is difficult to image the continents
before 650 million years ago.
b)
What was the world’s climate during the late Precambrian?
c)
What is the explanation for why the climate was like this at this
particular time?
Return
to the main page and continue to look at the maps for each of the geologic
periods.
12) During the Cambrian, what
was the condition of the continents and what was the new continent that formed?
13) Ordovician.
What were the three major oceans at this time?
14) What two continents collided during the
Silurian and what new continent did they form?
15) The closing of which two continents during
the Early Carboniferous created the
16) What did western Pangaea look like during the
Permian?
17) What was the name of the ocean during the
Jurassic?
18) When did Pangaea start to break up?
19) What did the middle of
20) What is the date on the extinction of the
dinosaurs and where is the crater from the meteorite located?
21) How long ago (I want a date) did
22) What was sealevel
like during the Miocene and how do you know?
23) When was the last Ice age?
24) How did the size and location of the
continents change from the Precambrian to today?