Layers of the Earth
Order the layers of the Earth (starting from the surface)
crust. mantle, outer core, inner core
During sea-floor spreading, where does magma rise from?
Along the mid-ocean ridge
Why did most geologist reject Wegener's idea of continental drift?
The forces that could move continents could not be identified
What type of rock is the oceanic crust made up of?
Basalt
When the ocean crust sinks into a deep-ocean trench, melts, and returns back into the mantle.
Subduction
How would you describe Earth's inner core?
Dense ball of solid metal
All the continents once were joined as a single supercontinent and have drifted apart. What is this called?
Continental drift
What is continental drift?
All the continents had once been joined togther in a single landmass
All the continents were once joined together in a supercontinent called ______________, meaning "all land."
Pangaea
What technology did scientists use in the mid 1900's to map the mid-ocean ridge?
sonar
In which layer of the Earth do convection currents flow?
Asthenosphere
If subduction occurs faster at a deep-ocean trench than oceanic crust can be created at a mid-ocean ridge, the seafloor ocean will____________________
Shrink
Any trace of an ancient organism preserved in rock is called_______
A fossil
What continually adds new oceanic crust to the ocean floor along both sides of the mid-ocean ridge?
Sea-floor spreading
Rocks farther away from the mid-ocean ridge are older than those near it. How did this get discovered?
Rock samples obtained from drilling
How do geologists study Earth's interior indirectly?
Studying the speed and path of seismic waves
An underwater canyon where oceanic crust bends downward is called______________
Deep-ocean trench
Scratches in rocks made by _________________ found in South Africa went along with Wegener's theory.
Glaciers
What causes convection in the Earth's mantle?
1. inner core gives off heat and this causes the bottom of the mantle to get warmer
2. this part of the mantle becomes less dense and rises
3. as is rises, it cools, spreads and sinks
What is the mid-ocean ridge?
Longest chain of volcanic mountains
The asthenosphere is the top part of which layer of the Earth?
The mantle
Name the geologist who studied the mid-ocean ridge and sea-floor spreading.
Harry Hess
Name 3 types of Alfred Wegener used to support his continental drift hypothesis?
1. landforms
2. fossils
3. climate
Pressure increases with depth toward the center of the Earth. In which layer would you expect pressure to be the greatest?
The inner core
In the asthenosphere, heat is slowly transferred in cycles known as_____________
Convection Currents