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Flashcards in Ch2 Deck (31):
0

The ___ are a logical evolutionary a analog of the Africa rift valleys ten million years from now

Red Sea

1

New oceanic crust and lithosphere are formed at

Divergent boundaries by submarine eruptions and intrusions of basaltic magma

2

Volcanoes and deep valleys of east Africa are related to a

Continental rift along which parts of the African continent are beginning to slowly separate

3

Which if the following most accurately describes the volcanoes of the Hawaiian islands

Shield volcanoes fed by a long lived hot spot below the pacific lithospheric plate

4

The temperature below which magnetic material can retain a permanent magnetization is called the

Curie point

5

The Aleutian Islands occur at a

Convergent boundary on a volcanic arc above a northward subducting Pacific plate

6

The__ is an example of an active, continent-continent collision

Northward movement of India into Eurasia

7

Deep focus earthquakes are associated with___ plate boundaries.

Convergent (subducting)

8

A transform plate boundary is characterized by ___

A deep, vertical fault along which two plates slide past one another in opposite directions

9

A typical rate of seafloor spreading in the Atlantic Ocean is

2 cm per year

10

A very long lived magma source located deep in the mantle is called a ___

Hot spot

11

All of following contribute evidence supporting the theory if plate tectonics except for __

Changes in the moons orbit due to shifting plates

12

Deep ocean trenches are surgical evidence for ___

Sinking of oceanic lithosphere into the mantle at a subduction zone

13

Deep ocean trenches are most abundant around the rim of the ___ ocean basin

Pacific

14

Cooler, older, oceanic lithosphere sink into the mantle at ___

Subduction zones along convergent plate boundaries

15

The continental drift hypothesis was rejected primarily because Alfred Wegener could not ___

Identify a mechanism capable of moving continents

16

Pull apart, rift zones are generally associated with

Divergent plate boundary

17

Linear, magnetic patterns associated with mid ocean ridges are configured as

Normal and reversed magnetized strips roughly parallel to the ridge

18

Which one of the following is an important fundamental assumption underlying the are tectonic theory

Earths diameter has been essentially constant over time

19

___ plate boundaries have the larger magnitude earthquakes

Transform and convergent

20

In the early part of the 20th century, ___ argued forcefully for continental drift

Alfred Wegener

21

On average, lithospheric plates ___ thick

100km

22

Where would you drill to recover samples of the oldest basalts of the oceanic crust, which are Jurassic in age?

Oceanic side of the Aleutian trench, along the southern coastline of Alaska

23

___ most effectively outlines the edges if the lithospheric plates

Iines of earthquake epicenters

24

___ first related the symmetrical magnetic patterns in seafloor basalts to seafloor spreading at a mid ocean ridge

Vine and Matthews

25

The ___ were formed in the late Paleozoic when sediments in a marine basin were squeezed and crumpled between converging continents

Urals in Russia

26

Mount St. Helens and the other cascade volcanoes are ___

Young, active volcanoes built on a continental margin above a sinking slab of oceanic lithosphere

27

T or f: during the geologic past, the magnetic poles have generally been very close to earths geographical poles

True

28

In general, rocks of the continental crust are less dense than rocks of the oceanic crust

True

29

In general, seafloor sediments gradually thicken away from a mid ocean ridge

True

30

As the south Atlantic basin widens by seafloor spreading, Africa and South America are moving closer together

False