Tectonics

Question 1

What is Geomorphology? What does it study specifically?

Answer 1

It is the science of landforms. It studies the origin, evolution, form, and spatial distribution

Question 2

How are landscapes formed?

Answer 2

Through the interactions between endogenic and exogenic processes

Question 3

Are plate tectonics an endogenic or exogenic process?

Answer 3

Endogenic

Question 4

What is the theory of “continental drift” and “pangaea”?

Answer 4

It was a theory by alfred wegener in 1912 and stated that continents floated on plastic material
He though this because:
•Noticed “fit” of the coastlines of the continents
•Found fossils indicating very different climates than today
•Matched large-scale features; e.g., Appalachian rocks match rocks in Scottish Highlands

Question 5

How was the theory of continental drift and pangaea received?

Answer 5

Hypothesis was harshly rejected by scientific world—no mechanism!
What would drive the movement?

Question 6

How is the Earth’s surface divided? What drives these movements?

Answer 6

The Earth’s surface is divided into a set of lithospheric plates that are in slow but steady motion. Movement of these plates is driven by heat from the Earth’s core

Question 7

What are endogenic processes?

Answer 7

Internal processes - work from within the Earth

Question 8

What are exogenic processes?

Answer 8

External processes - work at the Earth’s surface. I.e, weathering by wind and water

Question 9

What is the crust? Where is it separated from the mantle?

Answer 9

the thin, outermost layer of the planet. The Earth’s crust is separated from the mantle by the boundary called the Moho.

Question 10

What happens at the Moho?

Answer 10

Seismic waves indicate that a sudden change in the density of materials occurs. This is due to a change in chemical composition

Question 11

What is the lithosphere? Where is it thickest and where is it thinnest?

Answer 11

It is the outer earth shell of rigid, brittle rock, including the crust and also the cooler, upper part of the mantle. It ranges in thickness from 60 to 150km, and is thickest under the continents and thinnest under the ocean basins

Question 12

How does the lithosphere compare to the asthenosphere?

Answer 12

The lithosphere is on top of the asthenosphere, and is a hard, brittle shell resting on a soft, plastic underlayer. The lithosphere floats on the plastic asthenosphere much like an iceberg floats on water.

Question 13

Who came up for the mechanism of continental drift theory, and what effect did it have on geosciences?

Answer 13

Harry Hess from Princeton. It is a paradigm shift in geosciences

Question 14

What does seafloor spreading do?

Answer 14

It produces new crust under the sea

Question 15

What are igneous rocks?

Answer 15

Are formed when molten material or magma solidifies

Question 16

What are sedimentary rocks?

Answer 16

Sedimentary rocks are made from layers of mineral particles found in other rocks that have been released by weathering. They also include rocks made from newly formed biomass and invertebrates.

Question 17

What are some common sedimentary rocks?

Answer 17

sandstone, siltstone, conglomerate, mudstone, claystone, shale, limestone, dolomite, chert, evaporites, coal, petrolem, natural gas

Question 18

What are some common igneous rocks?

Answer 18

rhyolite, granite,diorite, andesite, basalt, gabbro

Question 19

What are metamorphic rocks?

Answer 19

formed by tremendous high pressures and temperatures that alter igneous and sedimentary rock into metamorphic rock

Question 20

what are some common metamorphic rocks?

Answer 20

slate, schist, marble, gneiss, quartzite

Question 21

What is some evidence for Pangaea?

Answer 21

Mirror images of rock ages on each side of a spreading ridge and magnetic reversals in polarity

Question 22

What is the energy source for Plate Tectonics?

Answer 22

• Earth’s internal heat from the decay of radioactive material
• Convection in the mantle (pushing and pulling)

Question 23

Presently, how many plates are moving around?

Answer 23

14

Question 24

What direction do the major plates (N. American, S. American, African, Eurasian, Indo-Australian, Pacific, Antarctic) move?

Answer 24

Look at map on slide 14

Question 25

What are the 3 boundary types that are between plates and what do they do?

Answer 25

Divergent, convergent, and transform boundaries. They have a strong influence on surface landforms

Question 26

What is a divergent boundary? Give an example.

Answer 26

New crust is formed as plates move apart and magma rises to surface. “zones of “extension”
new crust is formed as plates move apart”

Surface expression: ridges

Question 27

Where are most divergent plate boundaries found?

Answer 27

In the middle of oceans

Question 28

What are convergent boundaries?

Answer 28

zones of “compression”

Plates collide and crust is “recycled”

Question 29

Where does the old crust go when plates converge?

Answer 29

Subduction. This is the descent of the edge of a lithospheric plate under an adjoining plate and into the asthenosphere

Question 30

What is subduction?

Answer 30

When an oceanic plate collides with a continental plate, the oceanic plate is subducted into the asthenosphere. This is because the oceanic plate is Oceanic crust is thinner but denser and heavier than continental crust. It always sinks below the thicker, but lighter, continental crust.

Question 31

Where are subduction zones often found?

Answer 31

Mostly along continental margins

Question 32

What do these subduction zones mark?

Answer 32

Convergent boundaries that are strongly associated with earthquakes and volcanism

Question 33

What happens when continental lithosphere meets continental lithosphere?

Answer 33

Orogeny. This is the folding of crust were two continental plates meet contributes to a mountain-building process

Question 34

In orogeny, how is the crust uplifted?

Answer 34

through folding and faulting

Question 35

What is a transform plate boundary?

Answer 35

Zones of lateral movement. Plates slide past each other without colliding. NO crust formed or destroyed (just bending, ripping, and faulting)

Question 36

What are transform boundaries sometimes referred to as?

Answer 36

“Transform faults”

Question 37

What do many transform faults connect?

Answer 37

segments of spreading ridges

Question 38

Where do some transform faults occur?

Answer 38

Continental margins