Section 1
What was the first piece of evidence, that even early mapmakers noticed, that the continents were once all together
Continents looks like they fit together like puzzle pieces
What was the name of the one large supercontinent?
Pangaea
How is sonar used to map the ocean floor?
Uses sound waves to measure water depth
A plate boundary where tectonic plates are moving away from each other is called ______ Do they usually occur on continents or the ocean floor?
Divergent plate boundary
Ocean floors
The transfer of energy by the flow of heated matter is:
Convection
What is the Continental Drift Theory
Earth's continents had once been joined as a single landmass
What was the scientists name who proposed the Continental Drift Theory?
Alfred Wegener
A change is Earth's magnetic field is called what?
Magnetic reversal
A type of plate boundary where tectonic plates are moving towards each other and another type where plates slide horizontally past each other are what two types of plate boundaries?
Convergent and transform boundaries
The upward and downward movement of warm and cold matter is:
Convection current
Why did people not fully accept the idea of the Continental Drift Theory for a long time?
The scientist who proposed the theory could not explain the what forces could move the continents
A device that can detect small changes in magnetic fields is called what?
Magnetometer
2 topographic features discovered using sonar & magnetometers:
Ocean ridges (underwater mountains)
Deep-sea trenches
What is a rift valley?
A long narrow depression that forms when continental crust separates in a divergent boundary.
What was the name of one of the fossils that was used as evidence for continental drift?
Kannemeyerid, labyrinthodont, glossopteris, mesosaurus
What is an isochron?
A line on a map that connects points of the same age.
2 discoveries produced using samples of deep-sea sediments & underlying crust
Ages of rocks
Thickness of the oceanic crust
What is subduction?
When one of Earth's tectonic plates slides or slips underneath another
What is the thought to be the driving mechanism of plate movements?
Convection currents in the mantle
What were the 4 pieces of evidence used to support the theory of Continental Drift Theory?
Climate changes, Fossil correlation, Rock formations (mountain ranges), Continents look like puzzle pieces
The name of the scientist who proposed Seafloor Spreading theory and define the theory.
Harry Hess
Seafloor spreading - New ocean crust is formed at the ridges and destroyed at the trenches.
Rock samples and sediments
Ages of the rocks
Topography of seafloor
Rock magnetism
When an elevated ridge pushes an oceanic plate towards a subduction zone what is this called?
Ridge Push
When a subducting plate pulls the trailing lithosphere into a subduction zone this is called:
Slab pull