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As part of a new program to give students work
experience, the school district has hired you to run the Geological
Heritage Project for your school district. The "GHP," as it
is known, will become the basis for an Earth science exhibit
that will rotate among district schools.
- You decide the thing to do is describe the
variety of rock types that give evidence to the sequence of
events in plate tectonic history of the Northeastern U.S.
You realize that you must be sure you know what kinds of rocks
are found in various parts of any average place where two
plates meet each other, before you go looking for rocks that
represent historical plate tectonic events in the Northeast.
You also realize that you will need to learn where to find
the most important rocks that represent the history of plate
tectonic events. a) Draw a cross-section of an area in which
two tectonic plates are converging, and another in which there
is a passive margin west of a mid-ocean ridge. Label all the
rocks (for example, granite, basalt, rhyolite or andesite,
schist, gneiss, shale, sandstone, conglomerate, and limestone)
and sediment types (mud, sand, gravel) one might expect to
find across these settings. b) Now that you've done (a), you
decide to document the existence of as many of these rock
types as possible from past geologic events in the northeast.
You ambitiously get funding from a local supermarket to send
out an expeditionary team of fellow students to collect sets
of geological samples from each historical event (but you
need to keep costs down). Naming the rocks, ages, and localities,
find the shortest highway route your fellow students should
take to collect rocks from the sedimentary basins associated
with: (1) Greenville passive margin (2) Taconic convergence
(3) Acadian convergence (4) rifting apart of Pangea (5) Coastal
Plain passive margin
- The Discovery Channel hears about the incredible
work you've done with the exhibit, and decides that making
a rockumentary - in this case the history of the rocks at
some particular point - would make a fascinating television
special. What better, they suggest, than to feature the history
of the rocks in your area. You will be the star of the show.
Although you've learned the sequence of events in the Northeast,
you realize that you don't know the detailed sequence of rock
types right in your own neighborhood. Draw a likely geologic
section of the types and ages of rocks under your home down
to the Precambrian basement and associate them with the major
events in the geologic history of the northeast.
- A tour developer watching the Discovery program
realizes that there's a new business opportunity for her.
Instead of human history tours, take advantage of the growing
popularity of nature tourism and give geological history tours.
She'll let you in on the profits if you'll get her started
- choose three different areas with rather different geological
histories and describe the history of each of them, and what
evidence in rock types can be seen of that history at the
surface. These will become the tour destinations. Teacher
tip: The American Association of Petroleum Geologists has
a map for the Northeast United States with both cross sections
and geological map that may suit your needs. Students may
be able to find some information on the Web that gives geological
maps and cross sections.
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