Plate Tectonics

Question 1

what is the main evidence for plate tectonics and continental drift

Answer 1

Seafloor spreading

Question 2

Why do magnetic reversals matter in MOR

Answer 2

Magnetic reversals(= a switch in the Earth’s magnetic field)were detected in bands parallel to mid-ocean ridges.

Question 3

What are earths chemical layers

Answer 3

Crust
Mantle
Core

Question 4

What is the core of the earth made of

Answer 4

outer liquid layer of iron and nickel and a solid inner core of metallic iron.

Question 5

What are the five main physical layers of the earth and what major element determines them.

Answer 5

1. Lithosphere
2. Asthenosphere
3. Mesosphere
4. outer core
5. Inner core
   and are determined by responses to stress

Question 6

what drives plate tectonics

Answer 6

Mantle Convection: arm material rises under mid-ocean ridges, cools and then sinks at subduction zones; conveyor belt analogy

Question 7

Define Lithosphere

Answer 7

the lithosphere is the outermost physical layer of the Earth. It is grouped into two types: oceanic and continental. Oceanic lithosphere is thin and relatively rigid. It ranges in thickness from nearly zero in new plates found around mid-ocean ridges, to an average of 140 km in most other locations. Continental lithosphere is generally thicker and considerably more plastic, especially at the deeper levels. Its thickness ranges from 40 to 280 km

Question 8

Define Asthenosphere

Answer 8

The asthenosphere is the layer below the lithosphere. Astheno- means lacking strength, and the most distinctive property of the asthenosphere is movement. Because it is mechanically weak, this layer moves and flows due to convection currents created by heat coming from the earth’s core cause. Unlike the lithosphere that consists of multiple plates, the asthenosphere is relatively unbroken.

Question 9

Define Mesosphere

Answer 9

The mesosphere, sometimes known as the lower mantle, is more rigid and immobile than the asthenosphere. Located at a depth of approximately 410 and 660 km below the earth’s surface, the mesosphere is subjected to very high pressures and temperatures. These extreme conditions create a transition zone in the upper mesosphere where minerals continuously change into various forms, or pseudomorphs

Question 10

How did alfred wagner influence plate tectonics

Answer 10

He introduced the concept of continental drift to the literature. However initially he was considered to be crazy.

Question 11

define continental drift

Answer 11

the theory that continents were initially put together like jigsaw pieces and overtime drifted apart.

Question 12

Define Wadati-Benioff zone

Answer 12

Several independent research groups recognized earthquake epicenters traced the shapes of oceanic plates sinking into the mantle. These deep earthquake zones congregated in planes that started near the surface around ocean trenches and angled beneath the continents and island arcs. Today these earthquake zones called Wadati-Benioff zones.

Question 13

What is a mid ocean ridge (mor) and how does it work

Answer 13

A divergent boundary within an oceanic plate, where new lithosphere and crust is created as the two plates spread apart. Mid-ocean ridge and spreading center are synonyms.

Question 14

Why does earths polarity matter

Answer 14

while parts of Earth’s outer core are too deep for scientists to measure directly, we can infer movement in the core by observing changes in the magnetic field.

Question 15

define active and passive margins

Answer 15

Active margins are places where the oceanic and continental lithospheric tectonic plates meet and move relative to each other
At passive margins the plates don’t move—the continental lithosphere transitions into oceanic lithosphere and forms plates made of both types. A tectonic plate may be made of both oceanic and continental lithosphere connected by a passive margin.

Question 16

Define divergent boundaries

Answer 16

At divergent boundaries, sometimes called constructive boundaries, lithospheric plates move away from each other. There are two types of divergent boundaries, categorized by where they occur: continental rift zones and mid-ocean ridges

Question 17

define convergent plate boundariers

Answer 17

Convergent boundaries, also called destructive boundaries, are places where two or more plates move toward each other. . Convergent boundary movement is divided into two types, subduction and collision, depending on the density of the involved plates

Question 18

Define subduction and explain subduction zones

Answer 18

Subduction occurs when a dense oceanic plate meets a more buoyant plate, like a continental plate or warmer/younger oceanic plate, and descends into the mantle.
It is generally accepted that subduction zones start as passive margins, where oceanic and continental plates come together, and then gravity initiates subduction and converts the passive margin into an active one

Question 19

define transform fault boundaries

Answer 19

A transform boundary, sometimes called a strike-slip or conservative boundary, is where the lithospheric plates slide past each other in the horizontal plane.
Some transform boundaries produce significant seismic activity, primarily as earthquakes, with very little mountain-building or volcanism. This type of transform boundary may contain a single fault or series of faults, which develop in places where plate tectonic stresses are transferred to the surface

Question 20

Which kind of plate boundary is associated with earthquake activity?

Answer 20

Subduction zones

Question 21

Which kind of plate boundary is new oceanic lithosphere formed?

Answer 21

Mid ocean ridge

Question 22

what is wilsons cycle

Answer 22

The Wilson Cycle is named for J. Tuzo Wilson who first described it in 1966, and it outlines the ongoing origin and breakup of supercontinents, such as Pangea and Rodinia. Scientists have determined this cycle has been operating for at least three billion years and possibly earlier.

Question 23

Define hotspots

Answer 23

First postulated by J. Tuzo Wilson in 1963, a hotspot is an area in the lithospheric plate where molten magma breaks through and creates a volcanic center, islands in the ocean and mountains on land. As the plate moves across the hotspot, the volcano center becomes extinct because it is no longer over an active magma source. Instead, the magma emerges through another area in the plate to create a new active volcano.

Question 24

What is the approximate velocity of the fastest-moving tectonic plates on Earth?

Answer 24

138-150 mm/y

Question 25

James Hutton***test question

Answer 25

Created Uniformitarianisim

Question 26

Uniformitarianism

Answer 26

Principle of Uniformitarianism
Idea championed by James Hutton that the present is the key to the past, meaning the physical laws and processes that existed and operate in the past still exist and operate today.