Continental Boundaries & Drift Flashcards
name the major plates in alphabetical order
African plate, antarctic plate, Eurasian plate, Indo-Australian plate, North American plate, Pacific plate, South American plate
How many major plates are there
seven
Hotter less dense material rises while cooler denser material sinks moves by cm/yr.
mantle convection
What causes plates to move?
moving mantle material aka basal friction
How slow does the slowest plate (Scotia) move?
0 cm/yr
How fast does the fastest plate (Indian) move
100 cm/yr
Secondary mechanism, gravity pushes oceanic plate away, higher elevation, Mid-ocean____
ridge push
The oceanic plate is pulled into the mantle and is destroyed/ converted into mantle material due to subduction. Also a secondary mechanism.
slab pull
What do characteristics of plates depend on?
location/way they move/ Oceanic or Continental
2 plats grind past each other.
transform boundary
plates are not created nor destroyed
transform boundary
powerful earthquakes are created
transform boundary
potential energy that builds then slips
transform boundary
no volcanoes
transform boundary
San Andreas Fault
transform boundary
frequent weak earthquakes that cause cities to move closer together
transform boundary
two plates move away from each other
divergent boundaries
small volcanoes & shallow/weak earthquakes
divergent boundaries
two types of divergent boundaries
1)oceanic-oceanic
2)continental-continental
Seafloor spreading and new floor built
oceanic- oceanic divergent
new oceanic basin
oceanic-oceanic divergent
How new crust is formed
oceanic-oceanic divergent
mid-ocean ridge that forms at the spreading center
oceanic-oceanic divergent
newest lithosphere
oceanic-oceanic divergent
Mid-Atlantic ridge:caused by Eurasia and North American plate in the North along with south america and africa in the south.
oceanic-oceanic divergent
Rift valley forms as ocean splits
central rift splits and ocean water fills it. new ocean basin forms.
continental-continental divergent
most action,plates move and slide towards each other
convergent boundaries
three types:
1) Oceanic-Oceanic convergent boundaries
2)Continental-Oceanic convergent boundaries
3) Continental-Continental boundaries
subduction zone, trench, into asthenosphere and converted into mantle material, Strong Volcanoes&Earthquakes
Continental/Oceanic convergent
Andes mountain range
continental/oceanic convergent
older cooler and denser crust slips below the other, causes volcano formation and island arcs, tsunamis,
oceanic/oceanic convergent
Japanese & Aleutian Islands
oceanic/oceanic convergent
no subduction, no compression, rise up, plates are compressed, folded & uplifted, causing formation of huge mountains, Earthquakes are weaker than transform boundaries but greater than divergent boundaries so medium
no volcanoes
continental/continental convergent
Himalayas
Continental/Continental Convergent
continents are part of the plate and they move slowly cm/yr. mantle convection and basal friction
plate tectonics
supercontinent, most of all land on Earth
Pangea
335 mya
Pangea
Pangea started to break up into smaller continents
175 mya
Mostly was in southern hemisphere and surrounded by global ocean.
Pangea
pan means
entire
gaia means
earth
due to divergent boundaries forming rift valleys pangea splits in two in
the first split
175 mya
two parts of Pangea
1) Laurasia
2) Gondwana
North America, Eurasia, Greenland
Laurasia
South america, africa, India, arabia, antarctica, australia
gondwana
Gondwana breaks into five major parts
150 mya
Laurasia breaks into North America+greenland= laurentia & Eurasia
60 mya
India runs into Asia and form the Himalayas in
35 mya
Isthmus of Panama connects North and South America which seperates the Atlantic and pacific ocean
2.8 mya
Supercontinents are
cyclical
Nuna
1.8 bya
Rodinia
1.1 bya
panotia
600 mya
Pangea Ultima
250 mya into the future . The supercontinent of the future
230 mya fossils found in Africa, South America, and Antarctica
Cygnognathus
250 mya fossils in India, Africa, and Antarctica
Lystrosaurus
250 mya fossils found in Africa & South America
Mesosaurus
250 mya fossils in africa, India, New Zealand & Australia, and Antarctica
Glossopteris