Development of Tectonic Theory

Question 1

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

Answer 1

the field of paleomagnetism

Question 2

paleomagnetism is the study of _____ magnetism

Answer 2

rock

Question 3

_________ is the study of rock magnetism

Answer 3

paleomagnetism

Question 4

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

Answer 4

iron, magnetic

Question 5

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

Answer 5

poles

Question 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.

Answer 6

rocks, magnetic

Question 7

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

Answer 7

relative

Question 8

what explained how the continents were moving?

Answer 8

sea floor spreading

Question 9

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

Answer 9

the poles were stationary and the continents moved

Question 10

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

Answer 10

oceanographers, seafloor

Question 11

What was the mechanism for plate motion?

Answer 11

sea floor spreading

Question 12

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

Answer 12

• pole reversal records.

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

Question 13

Mid-sea ridges made of the ______ rocks

Answer 13

youngest

Question 14

sea floor spreading happens when…

Answer 14

the sea floor splits apart at mid-ocean ridges

Question 15

where does sea floor spreading happen?

Answer 15

at mid-ocean ridges

Question 16

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

Answer 16

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

Question 17

The plate tectonic model is a…

Answer 17

coherent model that explains continental drift and certain landforms

Question 18

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

Answer 18

– Mid-ocean ridge
– Volcanic island arcs

– Chains of volcanoes

– Mountain ranges

Question 19

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

Answer 19

asthenosphere

Question 20

the lithosphere is broken into…

Answer 20

giant plates that move around

Question 21

What is produced as plate boundaries interact?

Answer 21

large-scale geoloigic features