My Notes for boundaries, absolute age, and climate change Flashcards
What are the 3 characteristics of matter/3 types of rock behaviour?
1) elastic
2) ductile
3) brittle
Rocks are…
ductile under___pressure
elastic under___pressure
brittle between___pressure
- low
- high
- high and low
The ___, particularly the___glows like a liquid.
- mantle
- asthenosphere
Where do diamonds come from?
the mantle
What are the 4 points of evidence for pangea with rock matching?
1) Archean/younger boundary in South America and Africa
2) Late paleozoic glacier
3) fossils in Gwondana
4) Appalachian/Caledonian Mountain Chain
When was there a massive glacier?
late paleozoic
What are the 2 points of evidence for glaciers?
1) glacial striations- pebbles get picked up by glacier and as it flows they scratch the surface of the rock. Track the direction of flow
2) glacial deposits- as glacier flows, it picks up debris. When ice melts, this debris is left behind, called till. Ancient deposits.
Pangea began to form around___Ma.
300
What created Pangea? Where did the Caledonian Orogeny take place? When did the final orogenic effects end?
Plate collision and the Caledonian Orogeny takes place along part of the Convergent Plate Boundary. Final orogenic effects end ~250 Ma
When was the break up of Pangea?
180 Ma
When was the amalgamation of Rodina?
1000 Ma
When was the breakup of Rodina?
700 Ma
When continents break up and collide,___is changing at the same time.
Climate
What is lateral continuity?
Layers aren’t just on surface of this hill, they go through body of hill and project through others. Some may have been eroded away. we run into this when we drill holes. Eventually the layers run out, but until then, they are laterally contingent.
Where is the magnetic axis alway at on average?
The axis of spin (the geographic north pole)
How many km does the magnetic pole move each year?
several
What is each spot the magnetic pole lands on called?
virtual geomagnetic
What tracks continent movement?
polar wandering curve
What carried old magnetic information with it when it moved?
continents
What are divergent plate boundaries?
plates moving away
What are convergent or collisional plate boundaries?
plates coming together
What are transform plate boundaries?
plates moving sideways
Average rate of continent movement? What is the range of continent movement?
Average = 2 cm/year Range = 0-10 cm/year
Where do earthquakes occur?
at plate margins
Does the entire fault slip at the same time an earthquake slips?
no
Where is the centre of earthquake slip?
Where the energy is released
How is absolute plate movement determine?
- from satellite map
- geological past –> apparent polar wandering curves
What do divergent plate boundaries result from?
earthquakes, MOR, rift valley, etc.
Continental breakup =
ocean formation
At what depth is there partial melting during subduction with c.p.b?
At about 200 km depth there is partial melting with subduction
What are trenches on the ocean floor caused by?
subduction