continental drift
continet join togather in a supercontinet called pangea
what is the theory of continental drift
what is the first step in seafloor spreading
magma rises from the mantle are a mid ocean ridge
what are convection current
The movement of hot materials in the mantle that help the tectonic plates
What is the evidence for matching coastlines?
Thes shape of continents , like south America and Africa fit together like puzzle pieces
What is the first layer of earth and what is its main features?
crust thin rocky outer layer coolest and least dense
how fast are the continent moving
a few centimeters per year
what is the second step
The magma cools and hardened forming new crust
What is a mid-ocean ridge?
An underwater mountain where new ocean crust form
What is a second piece of evidence for continental drift?
similar fossials
What are the main features of the mantle?
Hot ,thick layer of rock the upper mantle asnosphere can flow slowly
who collect evidence continental drift
Afered Wegener
what was the third step
The new crust pushes the old crust to both sides
What is a rift?
A long crack in earth crust where plates are pulling apart
How are similar rock types evidence for continental drift?
The same types and ages of rocks are found on different continets
What is the outer core made of?
liquid , iron and nickel
how many years ago do Pangaea formed
300 Millon years ago
what is the fourth step
This process slowly moves the plates apart
What is a trench?
A deep valley in the ocean where one plate moves under another plate
How are glacial scratches evidence for continental drift?
Matching marks from accent glaciers show that these continents were once I the same area
What is the inner core made of?
solid iron and nickel hottest layer and most dense
what is evidence of Pangaea
matching coastline rock and fossials
where is the newer and older crust
newer crust is at the mid ocean ridge , the older crust is farther away from the ridge.
What is magma?
Hot , melted rock beanth earth surface
When will Pangaea break apart?
180 Millon years ago
What are the names for the 2 seismic waves that geologists use to study earth's interior?
p-waves and s-waves