EESA06H3 Lecture 6: EESA06H3 lecture 6
EESA06H3: Lecture 6:
The Death of Oceans-Toward the next supercontinent (Lectures 6-7).
• Why is this important?
o Pangea and the Tethys ocean
o India collides with Asia after 25 Ma closing the Tethys oceans and creating
the Mediterranean Sea during the Alpine-Himalayan orogeny
o Paifi i of Fie: ioles idespead sudutio ad elt of Pacific
Ocean crust below surrounding continents; continental crust is produced in
the process
o Provides a model for growth of continents in the past (ex: North America)
and key information about natural hazards around the Pacific Rim, and their
effects on cities.
• Why do mature oceans ultimately close?
o Outer margins of ocean plate are dense and thick and become too heavy and
begin to subduct back into the mantle creating a subduction zone that then
consumes ocean floor crust at a rate faster than which it is being produced at
mid-ocean ridge. This reverses direction of continental movement and closes
the ocean.
• The key feature about Rodinia is that much of the crust that underlays Ontario and
other places did not exist before that 1 billion years ago.
• Neo-Tethys or Tethys Ocean: located between Gondwana and
Laurasia.
o Obducted: To be pushed onto a continent
• Alpine-Himalayan Orogeny: caused by closure of Tethys. Creates
a collusion zone of high mountains made of deformed oceanic
rocks from Western Europe to Australia.
o Brown on the diagram
▪ Major mountain ranges.
▪ All composed of ancient ocean crust.
• Mediterranean Sea is a remnant of the Tethys Ocean. In the next
20-30 million, the Mediterranean Sea will be closed (destroyed), and the mountains
will get bigger.
• Matterhorn (The African prong): Euope’s highest outai. Made of Afia ust,
it was detached from the African plate, and moved all the way North. 4478 m.
o Therefore, there are major Earthquakes in Italy.
• Mountains record crust or thickening between colliding continents. What cuts the
mountains of the rocks? Glaciers, ice caps.
• The thick crust is produced by the collision and then ice,
snow, water will do the sculpting.
• Evidence that folded Tethys ocean rocks in the Alphs are
oceanic rocks:
o marine fossils
o a lot pillow basalt in there too (tells you basalt
was erupted underwater).
• Turkey, in the Anatolian plate, does not want to get
trapped in the collision between Europe and Arabian
find more resources at oneclass.com
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Document Summary
The death of oceans-toward the next supercontinent (lectures 6-7): why is this important, pangea and the tethys ocean. India collides with asia after 25 ma closing the tethys oceans and creating the mediterranean sea during the alpine-himalayan orogeny: (cid:862)pa(cid:272)ifi(cid:272) (cid:396)i(cid:373) of fi(cid:396)e(cid:863): i(cid:374)(cid:448)ol(cid:448)es (cid:449)idesp(cid:396)ead su(cid:271)du(cid:272)tio(cid:374) a(cid:374)d (cid:373)elt of pacific. Laurasia: obducted: to be pushed onto a continent, alpine-himalayan orogeny: caused by closure of tethys. 20-30 million, the mediterranean sea will be closed (destroyed), and the mountains will get bigger: matterhorn (the african prong): eu(cid:396)ope"s highest (cid:373)ou(cid:374)tai(cid:374). Made of af(cid:396)i(cid:272)a(cid:374) (cid:272)(cid:396)ust, it was detached from the african plate, and moved all the way north. 4478 m: therefore, there are major earthquakes in italy, mountains record crust or thickening between colliding continents. Now a solfatara, usually associated with dying volcanoes because at the end of the life cycle they produce gas (sulfur dioxide). No eruptions anymore, its dead: stromboli volcano: e(cid:396)upt f(cid:396)e(cid:395)ue(cid:374)tly (cid:271)ut (cid:374)ot (cid:448)e(cid:396)y da(cid:374)ge(cid:396)ous.
