Earth Flashcards
(31 cards)
What are earths layers?
Crust,Mantle,Inner and outer core
What are the two types of crust found on earth
ocean and continental crust
What is crust composed of?
outer surface of rock. Granite Basalt
How thick is earths crust?
3-5 miles, Very thin
What are plates
slide over hot and bendable layer of the mantle
What is the lithosphere?
crust and upper layer of mantle together make a ridged, ,brittle rock
What is a mantle?
Largest layer of rock
Hot dense rock that flows
Whats the function of the middle mantle?
The mantle convects heat from the outer core up to the crust
Whats the composition of the mantle?
Rocky layer under crust
What are convection currents?
caused by the very hot material at the deepest part of the mantle rising, then cooling and sinking again
What is outer core and what is it composed of?
Hot ball of metal
metals in liquid state
composed of melted nickle and iron
What is the inner core and what is it composed of?
Temps and pressures so great that metals are squeezed together
Why can inner core act as a solid?
Metals don’t melt because of high pressure
Forced to viberate like a solid
Who proposed the Pangea theory?
Alfred Wegner
What are the 4 pieces of evidence that supports the Continental Drift Theory
- Continents fit together like a puzzle
- Fossils match across oceans
- Rock types and mountain ranges match
- Glacial deposits
What is sea floor spreading?
Ocean moves carrying continents
New ocean floor forms along cracks in the ocean
New floor added
What are magnetic stripes?
Rocks that make up ocean floor lie in a pattern which hold record of magnetic field
3 peices of evidence that support seafloor spreading
Molten material- pillow shaped rocks
shows molten has erupted again and again
Magnetic stripes
Drilling samples
What is the plate tectonic theory?
Along the mid-ocean ridge the seafloor is pulling apart and the two parts are moving in opposite directions, carrying along the continents and oceans that rest on top of them.
what are 3 types of plate bounderys?
Divergent (pulling away)
Convergent (Crashing head on)
Transform (sliding past eachother)
Features of divergent boundaries?
causes rift valleys and mid ocean ridges
Rifting causes sea floor spreading
What is subduction zone?
region where tectonic plates meet
what happens when Covergent plate boundaries collide:
Ocean to continent: more dense slides under less dense
Ocean to Ocean: older, more dense slides under less dense
Continent to continent: They push together and create mountains
What is a transform boundary?
Fault along plate boundary
