Tectnoics Flashcards
How many tectonic plates are there in total?
52
Name the major tectonic plates
African
Antarctica
Eurasian
Indo Australia
North American
South American
Pacific
Name the minor tectonic plates
Caribbean
Cocos
Arabian
Juan de Fuca
Scotia
Indian
Nazca
Philippine 
Two examples of microplates
Nubian
Sunda plate
Where are earthquakes found
Collision, Conservative destructive, divergent

Where are volcanoes found?
Divergent and destructive
What are hotspots?
Places that are not on a plate Boundry yet have tectonic activities such as Hawaii
Where are tsunamis
Destructive plate along the coast
Describe oceanic lithosphere
Thickness density, rock type, age, formation, subduction 
Thin, 7 km
more dense 3.3 g/cm³
basaltic
youngest less than 200 million years
Formed at mid ocean ridges from seafloor spreading
subducts
Describe continental lithosphere
Thickness density, rock type, age,, subduction

Thicker up to 70 km
less dense 2.7 g/cm³
made of granites ,
oldest more than 1500 million years
does not subduction.
.
How is continental lithosphere formed?
Amalgamation of rock formed from volcano’s and hotspots as well as sedimentation
Pass through rock cycle, mountain building and erosion and metamorphism
Three ways mantle melts 
Addition of heat, mantle plumes and hotspots.
Addition of water, hydration, melting/slab dehydration at convergent plate, boundaries
less pressure, decompression, melting, divergent boundaries
How do convection currents occur
In upper mantle - asthenosphere partially melted - molten magma rises - convection currents occur
Describe ridge Push and Slab Pull
slap pull - weight of subducting wave pulling a plate in a certain direction
ridge push - force of magma forcing its way thro cracks btw plates and solidifying to form new crust pushing plates apart
Describe a Basaltic lava 
Temperature silica, content, gas, content viscosity, where it’s found  lava flow 
1000 to 1200°C
low silica content
Low gas content
low, viscosity
gentle effusive
divergent plate, boundaries, hotspot, and mental plumes 
Describe Andesitic Lava
Temperature silica, content, gas, content viscosity, where it’s found lava flow
800 to 1000°C
high silica content
more gaseous
high viscosity,
violent and moderately, explosive eruptions, convergent plate boundaries - hydration melting
Why Andesitic Lava more viscous
Do you hydration melting parts of crustless, lisopher and mantle melts together - release minerals 
What is an earth quake
Sudden release of energy that generates seismic waves 
Why do earthquakes occur? 
Along fault lines, plates become locked because of friction
opposing tectonic plates, buildup, pressure and strain
which eventually releases stored energy suddenly as a quake
What is the focus?
Focus point of rupture where the strain energy was released from 
What is the epicentre?
The point on Earth surface directly above the focus of the earthquake 
Describe the global distribution of seismic activity - PDA
distributed, unevenly belts along plate boundaries
examples of pacific ring of fire has the most seismic activity combo of convergent plate in conservative plate boundaries.
Hotspot volcanoes in centre of tectonic plates, intraplate earthquakes
Describes a global distribution of volcanicity 
Narrow linear belt along plate, boundaries
continental oceanic, convergence in Mount Saint Helens 
Hotspot working is there such as Hawaii or Yellowstone Deasa more scattered an individual often due to mantle plumes 
Describe global distribution of tsunamis
Occurs at the edges where o+o or c+o often caused by earthquakes causing a vertical displacement of water
2011 Japanese tsunami
Tsunamis can occur as a result of a volcanic of activity e.g Krakatau
Example of a divergent plate boundary
North American and Eurasian plates, moving away, causes the mid-Atlantic ridge
 How do mid ocean ridges occur
Manta rises, below surface,
pressures, lowered, decompression, melting
Rocks partially melt.
Plumes of magma, melt the crust above, crust expands on heating and up domes
split and volcanism begins convection currents in the way is the cost as a moves away from rift causes, lateral tension results in parallel faulting. Allow central section to subside into magma, creating a rift Valley