Tetonic Plates Flashcards
What’s the continental drift theory
all continents were together at some point, then something caused them to drift apart over time
All the continents together were called…
Pangea
Pangea consisted of…
Laurasia
Gondwana
Laurasia consisted of
North America, Europe and Asia
Gondwana consisted of
South America
Africa
India
Australia
Antarctica
Three types of evidence of the continental drift are
Fossils
Mountain ranges
Ocean floor spreading
Explain fossils, in context of evidence of the continental drift
Mesosaurus were land animals that couldn’t swim.
Their fossils were found in both South America and Africa.
Therefore, continents were once connected.
Explain mountain ranges, in context of evidence of the continental drift
Mountain ranges in Pangaea, were lined up and were formed of rocks that were the same type and structure
Therefore, continents were once connected
Explain ocean floor spreading, in context of evidence of the continental drift
The Atlantic ocean didn’t exist during Pangaea. It appeared once the continents started drifting apart.
This is ocean floor spreading
therefore the continents were once connected.
What are tectonic plates?
*A section of earths crust that can move on the mantle
Due to sections being formed from deformed crust due to heat rising from the mantle
What are plate boundaries?
The edges of tectonic plates
Name some plates (7 at least)
Pacific
North American,
Nazca,
South American,
African,
Eurasian,
Arabian,
Indian,
Philippine,
Indo Australian,
Antarctic,
Caribbean
Explain how plates move (3)
Idrk it’s fine
Heat inside earth rises from core and spreads through the mantle
via convention currents
Name the different types of plate boundries (3)
Convergent
Divergent
Passive/transverse
Explain convergent
Moves towards each other
Explain divergent
Moving part
Explain transverse
Plates sliding past each other
Folded mountain ranges (3)
*Form along convergent plate boundaries
*Folds up and lift sedimentary rock between them
*Forms fold mountains
Landforms associated with different plate boundaries are (
*folded mountain ranges
*ocean floor spreading
*oceanic trenches
Ocean floor spreading + mid oceanic ridges (1:3)
*Occur along divergent plate boundaries involving 2 oceanic plates
*Plates pull apart, magma rises and solidifies
and new land is created
Oceanic trenches
*Oceanic plate converges with a continental one
*Oceanic plate Is denser so it slides under continental plate
*Seabed forms a trench under subduction zone
Subduction zone definition
A deep trench on an ocean floor
Where an oceanic plate is drawn under along a plate boundary
Constructive plate boundary
Plate boundary where new land is formed
Deconstructive plate boundary
Plate boundary where land is being destroyed
Warping definition (3)
*Rocks Change shape when compressed from sides
*Compressional forces aren’t that strong
*Rocks bend slightly
Folding definition
*Bending of rocks into folds
*Due to strong compressional forces from the sides
Types of folds depend on…
The degree of compressional force to rocks
Symmetrical fold
Axial plane is vertical
Asymmetrical fold
Axial plane is inclined
Overturn
Axial plane is inclined to the extent that strata on one limb is overturned
Overthrust fold (3)
Pressure’s very great
Fold breaks
A limb is pushed forward into another limb
Landforms associated with folding
Synclinal valleys and anticline ridges turn into synclinal ridges and anticlinal valleys due to erosion
Shield definition
Stable parts of crust that fairly flat plateau due to little movement.
Basin definition
Large lowland region between Shields and fold mountain ranges.
Rock faulting definition
A crack that forms in rocks due to continuous tension and compression forces
What’s a fault line
Line along earths surface where a fault occurs
Types of rock faults (3×2)
Normal [tension pulling em apart]
Tear/transform [moving past each other]
Reverse [compression towards each other]
Landforms associated with faulting
(3)
*fault scarp
*block mountain
*rift valley
Fault scarp definition
Steep slope
that forms along a fault line
where rocks slide up and down
Block mountain definition
Block of land uplifted
Between partalel faults
Rift valley definition
Block of land
That slips down between parallel faults
