Science - chapter 17- continental drift
Magnetometer
A device used to map the ocean floor detects small changes in the magnetic field
Sonar
A device used to measure water depth
An example of rock formation:
Similar rock structure is found on north america and the british isles
______ uses sound waves to measure water depth
Sonar
What were the two devices used to prove that the continents did move?
Sonar and magnetometer
What is a pangaea?
All of the continents that formed as one land mass
Pangaea
Ancient landmass made up of all of the continents that begin to break apart
Why was wegeners hypothesis rejected?
Because he couldnt explain how the continents could move
Magnectic reversal
Changes in earths magnetic field over geologic time
Reverse magnetic polarity is where the _______ magnetic polenis close to the _______ north geographic pole
North, north
Normal polarity is where the ______ magnetic pole is close to the _______ geographic pole
North, south
Coal beds found in Antarctica indicated that this continent was....
Once closer to the equator
What is the key piece of evidence for sea floor spreading?
Paleomagetism
An example of fossils:
Remains of an animal is found on south america and africa
Subduction is when new ocean crust is formed at the ______ and pushes old rock into the ________
Ridge, deep sea trench
What is earths magnetic field caused by?
The flow of molten iron in earths core
Panthelessa
The ocean surrounding the Pangaea
Isochron
A line on a map that connects points of the same age
Narmal polarity
A magnetic field that has the same orientation on earths present field
Deep-sea trenches
A narrow, elongated depression in the sea floor with steep sides
Seafloor spreading
A theory that new ocean floor is formed at mid ocean ridges and destroyed at deep sea trenches
True or false - as you move further away from a ridge the thickness of sediments decrease
False
True or false - most scientist supported wegeners hypothesis of continental drift.
False
Fossil evidence
Fossils of land animals and plants on different continents
Name the four pieces of evidence that was used to determine the continental drift:
Jigsae puzzle, rock formation, fossils, climate evidence
What is the study of the history of earths magnetic field
Paleomagetism
Paleomagetism
The study of earths magnetic records
Evidence from rock
There are the same rock types and layers mountain ranges on other mountain ranges on other continents
Climate evidence
Tropical and fossil evidence in Antarctica
True or false - rocks of the ocean floor increase with age as you move away from the mid ocean ridge
True
Ocean ridge
Under water mountain chain
Continental drift
Wegener's hypothesis that Earth's continents were joined as a single landmass that broke apart about 200 million years ago