Review They are found at the surface of the Earth Where are the continental and oceanic plates found? _____________________________________________ What is the difference between continental crust and oceanic crust? What is a tectonic plate made of? The upper and lower mantle The lithosphere and asthenosphere The crust and the lithosphere the crust and the asthenosphere They are found at the surface of the Earth The continental crust is land while the oceanic crust is the ocean floor.
Diverging/Divergent Boundaries
convergent divergent transform A boundary is where two plates meet together. There are three main types: convergent divergent transform
away continental oceanic A diverging boundary occurs where two tectonic plates move ________ from each other or are spreading apart. What happens depends on whether the plates involved are _____________ or _____________. continental oceanic
Two Oceanic Plates (under water)
Two Oceanic Plates (under water)
Two Oceanic Plates (under water)
Two Oceanic Plates (under water) The magma shoots to the surface The magma __________ down and _____________ _________________: the magma is pushed aside by new magma coming from below The entire process is called seafloor spreading cools solidifies ridge push
Two Oceanic Plates (under water)
Two Oceanic Plates (under water)
Two Continental Plates (on land)
rift valley Two Continental Plates (on land) There is a weakened spot on the plate Land sinks down and creates a _________ rift valley
Divergence of African and Arabia plates formed the Red Sea
For both cases, large amounts of magma can be released (called a ___________________) through the crack. This may result in the creation of a _____________. rift eruption volcano
Plates move so slow, we don’t see them move Plates move so slow, we don’t see them move. How do we know that seafloor spreading occurs?
Mapping the Seafloor
Mapping the Seafloor
mountain ranges Atlantic Ocean Mid-Atlantic Ridge Mid-Ocean Ridge Mapping the Seafloor Explorers began to map the seafloor discovered underwater ____________________ discovered a huge ridge from North to South in the middle of the ___________________ (80 000 km) the ridge is called the _____________________ or the _____________________ mountain ranges Atlantic Ocean Mid-Atlantic Ridge Mid-Ocean Ridge
Age of Ocean Rock and Sediments Young rock Young rock Old rock Old rock
Age of Ocean Rock and Sediments
Paleomagnetism paleomagnetism
spinning reverse magnetic reversal Paleomagnetism Earth has a magnetic field due to its ____________ core. every 10 000 – 100 000 years the _______________ in a process called _____________________ magma contains _______, which is attracted to magnetic fields when magma cools, the iron gets “___________” in a certain direction using a magnetometer, scientists found that rocks on either side of the Mid- Atlantic Ridge had a stripe pattern of alternating polarities the _____________________ pattern shows that new rock was being made over time reverse magnetic reversal
Paleomagnetism
spinning reverse magnetic reversal iron trapped magnetic striping Paleomagnetism spinning Earth has a magnetic field due to its ____________ core. every 10 000 – 100 000 years the _______________ in a process called _____________________ magma contains _______, which is attracted to magnetic fields when magma cools, the iron gets “___________” in a certain direction using a magnetometer, scientists found that rocks on either side of the Mid- Atlantic Ridge had a stripe pattern of alternating polarities the _____________________ pattern shows that new rock was being made over time reverse magnetic reversal iron trapped magnetic striping
Paleomagnetism
Hot Spot
continental drift
Unifying Theory of Geology