Download Earth is made of materials with different DENSITIES The 4 layers of

1. Earth is made of materials with different DENSITIES
2. The 4 layers of earth, in order from most outer layer to most inner layer, are a) CRUST
b)
MANTLE
c) OUTER CORE
d) INNER CORE
3. German scientist, ALFRED WEGENER proposed the hypothesis of CONTINENTAL DRIFT. 3 things that
provided evidence for this are 1)
FOSSILS
2) CLIMATE
3) GEOLOGY
4. The mapping of the sea-floor helped develop the theory of PLATE TECTONICS
which states that along
spreading centers in the sea floor MAGMA__rises through cracks, then HARDENS, and forms new crust that
builds up MID__ - OCEAN RIDGES . Even though the old crust gets pushed aside, and the sea floor spreads
apart, the earth doesn’t get larger because the old crust is destroyed along deep ocean trenches, where the
oceanic plates sink into the ASTHENOSPHERE. The 3 motions that move Earth’s huge tectonic plates are 1)
CONVECTION CURRENTS
2)
RIDGE PUSH
3) SLAB PULL
5. A plate boundary is where 2 plates move together. A DIVERGENT boundary occurs where plates MOVE
APART. Most of these boundaries are found in the OCEAN. A CONVERGENT boundary occurs where plates
push together. A TRANSFORM boundary – where 2 plates scrape past each other.
6. Sea floor spreads apart at DIVERGENT BOUNDARIES. MID-OCEAN RIDGES & RIFT valleys occur at divergent
boundaries. Mid-ocean ridges form the longest MOUNTAIN chains on Earth. The largest mid-ocean ridge is
the MID-ATLANTIC RIDGE which runs about _____ miles through the ATLANTIC Ocean. Most mid-ocean ridges
contain a RIFT VALLEY along the center.
7. Magma rising through cracked, thinned crust forms VOLCANOES. If the RIFT VALLEY continues to widen, the
thinned valley floor sinks BELOW SEA LEVEL & water from nearby oceans or rivers may fill the valley and form
a LAKE or SEAS.
8. A HOT SPOT can provide a fixed point for measuring the speed & direction of plate movements because it
generally stays in one place where the magma rises in a plume from the mantle.
9. Tectonic plates push together at CONVERGENT boundaries. There are 3 types of these boundaries. A)
CONTINENTAL-CONTINENTAL BOUNDARIES occur where 2 continental plates collide, crumpling & FOLD rock
between them. If rocks push high enough, they form FOLDED MOUNTAINS. B) OCEANIC-OCEANIC
BOUNDARIES/SUBDUCTION occur when 2 oceanic plates collide & the older, more DENSER plate SINKS
beneath the top plate, forming DEEP-OCEAN trenches & ISLAND ARCS . C) OCEANIC-CONTINENTAL
BOUNDARIES/SUBDUCTION occur where an oceanic plate SINKS beneath a continental plate, forming a DEEP
OCEAN trench & volcanic COASTAL MOUNTAINS
10. 2 plates move past each other in opposite directions at TRANSFORM boundaries. NO crust is CREATED or
DESTROYED at this boundary. These occur on the sea floor & land.