(10/24/2024) Global Tectonics - Plate Motion

Question 1

Mid-ocean ridges

Answer 1

Sharp ridges running across ocean basins

Question 2

Seafloor spreading

Answer 2

Process of new oceanic crust creation at mid-ocean ridges

Question 3

Magnetic anomaly maps

Answer 3

Evidence for seafloor spreading

Question 4

Magnetic polarity reversals

Answer 4

Changes in Earth’s magnetic field orientation

Question 5

Geomagnetic polarity

Answer 5

Normal or reversed orientation

Question 6

Chronology of polarity reversals

Answer 6

Used for dating rocks and determining plate rates

Question 7

Plate Rates

Answer 7

Speed of tectonic plate movement relative to each other

Question 8

Half-spreading rate

Answer 8

Rate of new oceanic crust creation at mid-ocean ridges

Question 9

Plate boundary

Answer 9

Where tectonic plates interact and move

Question 10

GPS technology

Answer 10

Uses satellites for location and movement tracking

Question 11

GPS data application

Answer 11

Measuring tectonic plate motion

Question 12

Reference frames

Answer 12

Coordinate systems for measuring position and velocity

Question 13

Relative motion

Answer 13

Movement of one plate relative to another

Question 14

Absolute motion

Answer 14

Movement of a plate relative to the deep mantle

Question 15

Hotspot tracks

Answer 15

Method to track plate motion relative to deep mantle

Question 16

Fast spreading rates

Answer 16

Smooth topography, small relief, hotter mantle

Question 17

Slow spreading rates

Answer 17

Rough topography, large relief, cooler mantle

Question 18

Example of fast vs. slow spreading rates

Answer 18

East Pacific Rise vs. Mid Atlantic Ridge

Question 19

Continental rifting

Answer 19

Process of continent splitting

Question 20

Rift valleys

Answer 20

Formed as continent stretches and thins

Question 21

Example of continental rifting

Answer 21

East African Rift System

Question 22

triple junctions

Answer 22

Point where three tectonic plates meet

Question 23

Type of triple junction

Answer 23

Ridge-Ridge-Ridge (RRR) Triple Junction

Question 24

Characteristics of triple junctions

Answer 24

Can be stable over long periods

Question 25

Convergent boundaries

Answer 25

Where two plates move towards each other

Question 26

Subduction

Answer 26

One plate forced beneath another, creating a trench

Question 27

Volcanic arc formation

Answer 27

Result of increasing heat and pressure

Question 28

Example of convergent boundaries

Answer 28

Aleutian Trench (Pacific Plate subducting under North American Plate)

Question 29

Divergent

Answer 29

Plates moving apart

Question 30

Convergent

Answer 30

Plates moving towards each other

Question 31

Transform

Answer 31

Plates sliding past each other

Question 32

Transform boundaries

Answer 32

Plates sliding past each other horizontally

Question 33

Characteristics of transform boundaries

Answer 33

Large-scale strike-slip fault

Question 34

Example of Transform Boundaries

Answer 34

San Andreas Fault (Pacific Plate and North American Plate)

Question 35

Location of the Mendocino Triple Junction

Answer 35

Meeting point of Pacific, North American, and Juan de Fuca Plates

Question 36

Significance of the Mendocino Triple Junction

Answer 36

Responsible for San Andreas Fault formation

Question 37

40 million years ago

Answer 37

Subduction of Farallon Plate under North American Plate

Question 38

30 million years ago

Answer 38

Formation of Mendocino Triple Junction

Question 39

20 million years ago

Answer 39

Formation of San Andreas Fault

Question 40

Pacific Plate movement

Answer 40

Northwest relative to North American Plate

Question 41

Rate of Pacific Plate movement

Answer 41

Approximately 50 mm/yr