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plate tectonics - Coggle Diagram

- - - - enormous pressure causes the continental plate to be uplifted and buckled- form fold mountains
        
        Earthquakes are very common as there is enormous built-up pressure
        
        Indo-australian plate and Eurasian plate- forms Himalayan mountain range
        
        2015 Nepal earthquake- 7,8 magnitude
    - - denser plate subducts under the less dense plate, creates subduction zone
        
        depression in the subduction zone is called oceanic trench
        
        magma rises through the crust and form chain of volcanoes
        
        earthquakes occur due to friction from subductions
        
        Pacific plate subduct underneath phillipine plate to form Mariana Islands and trench
        
        Guam, near the trench commonly have earthquakes
    - - denser oceanic plates subducts under less dense continental plate
        
        every thing in O-O and C-C
        
        Denser Nazca plate subducts under South American plate
        
        forms Peru-Chile trench,Andes fold mountain range and Nevado del Ruiz volcanoes
        
        2010 Chile Earthquake-8.8. magnitude
  - - - Earthquake occurs when one plate suddenly slip past
        
        Pacific plate slides pass North American plate- san adreas fault
        
        1989 Loma Prieta Earthquake- 6.9 magnitude
  - - - decrease in overlying pressure causes the underlying mantle material to melt, forming magma
        
        magma rises from the mantle to fill the gaps
        
        mid-ocean ridge is formed where oceanic plates diverge
        
        centre of the ridge is a deep rift valley with steep sides
        
        submarine volcanoes form along the central rift valley
        
        surtsey island,iceland
    - - rock fractures and form parallel faults
        
        rocks between the faults collapse, forming a deep rift valley with steep sides
        
        earthquake happens when stress and tension is released when the plates move
        
        decrease in overlying pressure causes underlying mantle to melt, forming magma
        
        magma rises through weak areas of the crust to form volcanoes
        
        Great African rift valley, diverging Nubian and Somalian plate
- - - - less dense, expand and rises and spread beneath the plates
        
        rising convection currents spread beneath the plates, dragging them apart, causing divergent plate movement
        
        The hot mantle material loses heat and sinks, pulling the plates along
        
        Point where magma sinks is the convergent boundary where sinking magma causes crust to move towards each other
  - - - gravity pulls the rest of the plate along into the mantle, contributing to further convergence
- - - - how it supports
        
        younger rocks are closer to the mid-ocean ridge and the age of the rocks get progressively older away from the ridge
        
        when new oceanic crust is formed, not enough time for sedimentation to accumulate
        
        oldest oceanic crust gets destroyed at oceanic trench while older crust have lots of sedimentation
  - - - when iron-rich lava erupts from the centre of the mid-ocean ridge ,cools and solidifies
        
        the magnetic field of the minerals in the lava will point towards the magnetic north at the point of solidification
        
        during a period of reverse polarity, the magnetic field of the minerals will point towards the reversed magnetic north