Opening of the South Atlantic Ocean
Loading takes a bit (each file
is 5k). After this page loads, use the mouse to scroll left or right through
geologic time, from the Present (0 Ma) back to the early Cretaceous (140
Ma). The time interval between frames is 10 Ma from 140 to 10 Ma,
then there are five frames at 5, 4, 3, 2, 1 and 0 Ma (present). For
more precise control, point the mouse in the frame, but use the arrow keys
on your keyboard to control the frames back and forth through time.
Notice some of the interesting
features of this model. Study the early opening history of the ocean
basin (140 to 80 Ma). How does South America open relative to Africa?
(note: this model is constrained so that Africa is motionless and S. America
does all the moving). After 80 Ma, the plate motion is different...
how so? These plate reconstructions were created using the
computer program GLG-Plates 2.1, by C.
E. Ford.
Opening of the South Atlantic Ocean again, but
cooler.
This model is similar to the one above, with a 10 Ma time step, but
by moving the mouse up or down, you get a different perspective on these
two plates (from 30 degrees north of the equator, or 30 degrees south).
Enjoy!
Puzzler: Here's a question to think about... You have just been
reading about sedimentary rocks that form in lacustrine environments (lakes).
You also read about the rift lakes of East Africa (Victoria, Tanganyka,
etc.) and that lakes formed along the eastern margin of North America during
the Triassic due to rifting. Well, you ask yourself, is it possible
that rift lakes formed when S. America and Africa rifted apart? If
so, when would the rift lakes formed (how many million years ago)?
And when would marine facies have invaded the area? Use these models
to address these questions, then look elsewhere on the net for the answers,
to see if you are right. Good luck.
This page contains a java applet that displays a VR
model. Java makes it possible to see multimedia content on many platforms
without downloading plug-ins or installing software. Visit FreedomVR
at www.honeylocust.com/vr/
for this cool Java applet.
Produced for WebDoGS by Paul Howell, 7/15/98.