Tectonics

Question 1

Earth’s outer shell is broken into _____ that move and interact in response to forces ____ the earth

Answer 1

lithospheric plates, within

Question 2

A single plate includes

Answer 2

crust (oceanic or continental or both)
uppermost rigid mantle

Question 3

Plates can move between ___ cm/year

Answer 3

0-10cm/year

Question 4

defn Plate boundaries

Answer 4

Places where two plates meet

Question 5

Are volcanoes randomly distributed? where do they happen?

Answer 5

No, plate boundaries

Question 6

Describe the age of rocks as the result of divergent boundaries

Answer 6

Divergent boundaries can exist on land but mostly exist on the seafloor
New oceanic crust is made in the middle because hot rocks rise up, melt and fill in the gaps creating new oceanic crust. These are called quenches
Rocks get older as you move perpendicualrly away from the ridge

Question 7

Quenches

Answer 7

New crust made my divergent boundaries
Hot rocks rise up, melt, create new oceanic crust

Question 8

Mid ocean ridge

Answer 8

A row of subsea volcanoes that wraps around the world produced because of sea floor spreading

Question 9

What geologic hazards are likely to occur at a divergent plate boundary>

Answer 9

Earthquakes
Volcanoes

Question 10

Why does the oceanic plate subduct>

Answer 10

More dense (thicker)

Question 11

Ocean continent covergent boundary

Answer 11

Oceanic crust subducts beneath continental plate
Deep trench forms ar boundary
Leading edge of cont crust gets compressed and deformed, producing mountains
Arc of volcanoes occurs on land above subducting plate

Question 12

How can we find fossilized sea creatures on tops of mountains?

Answer 12

Sea floor that has formed mountain peaks

Question 13

Ocean-ocean convergent boundary

Answer 13

two oceanic crust plates collide
Older, colder, denser plate subducts
Arc of volcanic islands forms on the overriding plate

Question 14

Continent-continent convergent boundary

Answer 14

Produces very large mountains
Ex. Everest

Question 15

Himalayan Mountains

Answer 15

Convergences of Indian and Eurasian plates

Question 16

In which boundary is no crust created or destroyed?

Answer 16

Transform

Question 17

Where do transform boundaries commonly form?

Answer 17

Along spreading cenres (divergent boundaries) to relieve stress

Question 18

The San Andreas Fault is a ____

Answer 18

transform fault

Question 19

What makes the plates move?

Answer 19

Heat is the source of power for plate movement

Question 20

Heat is slowly being released to the surface of the earth through ____ in the ____

Answer 20

convection in the mantle

Question 21

Tectonic plates likley move because of the realtively __ density of ____ and the relative ___ of the ____

Answer 21

high density of oceanic lithosphere and the realtive weakness of the asthenosphere

Question 22

What causes plate movement? 2

Answer 22

1. Plates pulled down into trenches (subduction zone)
2. Plates driven down the slope from the ridge to trench by gravity

Question 23

How do we know where the continents used to be?

Answer 23

We can look at the similarity of fossils and rocks on different continents

Question 24

Geological evidence of pangea 2

Answer 24

1. Rocks of the same age and type are found on continents that are now separated by oceans
2. Ancient mountain belts have also been split across divergent boundaries

Question 25

What did pangea look like before the dinos?

Answer 25

Single super cont
Ice sheets over S pole
Glacial tilts

Question 26

What did pangea look like ar the time of the first dinos?

Answer 26

Pangea shifts N
Ice sheets melt
Animals can migrate, achieving wide distributions alhtough moutnains block some passages

Question 27

What happens to the ocean level when pangea breaks apart?

Answer 27

Pangea starts to break up, ocean levels rise

Question 28

What do rising sea levels cause?

Answer 28

Inland seas

Question 29

What are the two smaller supercontinents?

Answer 29

Laurasia (N) and Gondwana (S)

Question 30

At the time of the meteorite (end of dinos) where are the continents? sea levels?

Answer 30

cont modern position
Seal levels start to drop bc glaciers form bc the dust and rock block sunshine