INTRO TO MARINE SCIENCE - Lecture 3

Plate Tectonics

Lithosphere

solid, rigid behavior

Which layer consists of the crust and upper lateral fused together?

Lithosphere

Asthenosphere

solid, ductile behavior

Which layer consists of a deformable region in the mantle?

Asthenosphere

Mesosphere

solid, mobile

Outer Core

liquid

Inner Core

solid

Isostasy

buoyant support of lithosphere by asthenosphere

What was the first evidence of the movement of continents according to Alfred Wagner?

North America, Europe, South America, Africa, and Greenland line up like jig-saw puzzles

What was the second evidence of the movement of continents according to Alfred Wagner?

mountain ranges on different continents line up

What was the third evidence of the movement of continents according to Alfred Wagner?

fossil evidence on different continents of the same species

What was the fourth evidence of the movement of continents according to Alfred Wagner?

climactic evidence that climate on different continents used to be the same

Why was Alfred Wagner’s theory for the movement of continents not widely accepted by the scientific community?

his theory for the mechanics behind the moving continents was incorrect, causing people to dismiss his whole idea

How do divergent boundaries move?

they move away from each other

How do convergent boundaries move?

they move towards each other

How do transform boundaries move?

the slide past each other

What happens at divergent boundaries?

• mantle upwelling

• layers of oceanic crust are generated

What happens at convergent boundaries?

• subduction

• volcanic activity

What happens at transform boundaries?

• offsets segments of ocean ridges

Where are rocks born?

divergent boundaries

Where are rocks destroyed?

convergent boundaries

Where are passive continental margins found?

Atlantic

Where are active continental margins found?

Pacific

Active continental margins

• tectonically active

• associated with earthquakes and volcanoes

• areas of plate convergence

• subduction of oceanic lithosphere

• narrow

Passive continental margins

• little to no seismic or volcanic activity

• transition from continental to oceanic crust

• formed at far margins of rifts/convergent boundaries

• wide

What is the geologic process of ocean-ocean divergent boundaries?

new seafloor created, ocean basin opens

What is the geologic feature formed from ocean-ocean divergent boundaries?

mid ocean ridges

Do ocean-ocean divergent boundaries cause earthquake or volcanism?

shallow earthquakes, and volcanism

Examples of ocean-ocean divergent boundaries

• mid Atlantic ridge

• east pacific rise

What is the geologic process of continent-continent divergent boundaries?

continent breaks apart, new ocean basin forms

What is the geologic feature formed from continent-continent divergent boundaries?

continental rift and shallow sea

Is there earthquakes and volcanism associated with continent-continent divergent boundaries?

shallow earthquakes, and volcanism

Examples of continent-continent divergent boundaries

• East African rift

• red sea

• gulf of aden

• gulf of california

What is the geologic process of both ocean-ocean and ocean-continent convergent boundaries?

old sea floor destroyed by subduction

What geologic feature is formed from both ocean-ocean and ocean-continent convergent boundaries?

ocean trench

Is there earthquakes or volcanism associated with ocean-ocean or ocean-continent convergent boundaries?

yes, shallow to deep earthquakes and volcanism

What are examples of both ocean-ocean and ocean-continent convergent boundaries?

Ocean-ocean

• Aleutian

• Mariana

• Tonga Trenches

Ocean-continent

• Peru-chile and middle America trenches

What is the geologic process of continent-continent transform boundaries?

mountain building

What geologic feature is formed from continent-continent transform boundaries?

mountain range

Is there earthquakes and volcanism associated with continent-continent transform boundaries?

shallow to intermediate earthquakes and no volcanism

What are some examples of continent-continent transform boundaries?

• himalaya mountains

• alps

What is the geologic process of both ocean and continent transform boundaries?

sea floor conserved (neither created or destroyed)

What geologic feature is formed from both ocean and continent transform boundaries?

transform fault (offset segments of ridge crest)

Are there earthquakes and volcanism associated with ocean and continent transform boundaries?

shallow earthquakes and not volcanism

What are some examples of ocean and continent transform boundaries?

Ocean

• Mendocino

• clipperton

Continent

• san Andreas fault

• alpine fault

• north and east Anatolian faults