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Flashcards in Development of Tectonic Theory Deck (21)
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1

What was a major development that contributed to the theory of plate tectonics?

the field of paleomagnetism

2

paleomagnetism is the study of _____ magnetism

rock

3

_________ is the study of rock magnetism

paleomagnetism

4

as magma solidifies and cools ____ bearing minerals actually align to earths ______ field

iron, magnetic

5

paleomagnetism allows us to tell when the Earth's ______ have switched

poles

6

by mapping _____ on the ocean floor geologists started to get weird results that showed that the Earth's _____ pole over the past 100 million years seemed to be migrating along the side of the Earth.

rocks, magnetic

7

continents and rocks themselves were moving ____ to the magnetic pole.

relative

8

what explained how the continents were moving?

sea floor spreading

9

what was the conclusion for the supposed movement of the poles? 

the poles were stationary and the continents moved 

10

There was overwhelming circumstantial evidence for continental drift, but no direct clues until ______ mapped the ages of ______ rocks 

oceanographers, seafloor 

11

What was the mechanism for plate motion? 

sea floor spreading 

12

When the ages of seafloor rocks were mapped using _____ ______ records, what did scientists find? 

- pole reversal records. 

 

– Mid-sea ridges made of youngest rocks
– Older rocks symmetrically situated on either side

13

 Mid-sea ridges made of the ______ rocks
 

youngest 

14

sea floor spreading happens when...

the sea floor splits apart at mid-ocean ridges 

15

where does sea floor spreading happen? 

at mid-ocean ridges 

16

How does the sea floor spread? What are the four components of the spreading process? 

1. Magma swells up and is extruded

2. Solidifying magma records the direction of the Earth’s magnetic field

3. Rock spreads out in a continuous spill

4. Older rock “pushed” away from the ridge and  younger rock takes its place

17

The plate tectonic model is a...

coherent model that explains continental drift and certain landforms 

18

What four contint-scale landforms are associated with contintal drift? 

– Mid-ocean ridge
– Volcanic island arcs 

– Chains of volcanoes 

– Mountain ranges

19

In the Plate tectonic model the lithosphere floats on top of the _________

asthenosphere 

20

the lithosphere is broken into...

giant plates that move around 

21

What is produced as plate boundaries interact? 

large-scale geoloigic features