ch9 study guide

Wegener’s continental drift hypothesis stated that all the continents once joined together to form….
a single continent
The super continent in the continental drift hypothesis was called…
pangaea, meaning all land
One kind of evidence that supports wegener’s hypothesis is that….
a.he noticed the similarity between the coastlines on opposite sides of the south alantic ocean.
b.fossil evidence for continental drift includes several fossil organisms found on different landmasses.and example is mesosaurus, an equatic reptile whose fossil remains are limited to eastern south america and southern africa.c.rock evidence for continental drift exists in the form of several mountain belts that end at one coastline, only to reappear on a landmass across the ocean.d.wegner found glacial deposits showing that between 200 million and 300 million years ago, ice sheets covered large area of the southern hemisphere
According to the theory of the plate tectonics, the uppermost mantle, along with the overlying crust, behaves as a strong rigid layer…
this layer is known as the lithosphere
In the plate tectonic theory, a plate can be made up of
What kind of plate boundary occurs where two plates grind past each other without destroying or producing lithosphere?
transform fault boundaries
What type of boundary occurs when two plates move together, causing one plate to descend into the mantle beneath the other plate?
convergant boundary
New ocean crust is formed at..
divergant boundaries
What hypothesis states that the continents were once joined to form a single supercontinent?
continental drift theory
Which of the following was not used in support of the continental drift hypothesis?
see #3 above
In the plate tectonics theory, the lithosphere is divided into..
A tectonic plate consists of…
uppermost mantle, along with overlying crust
Which of the following is the geographic example of a transform fault boundary?
san andreas fault
Which of the following results when divergence occurs between two oceanic plates?
divergence creates new seafloor. divergence causes ocean ridges and rift valleys
The himalayas in south asia are an example of what type of plate boundary?
convergant boundary and result of continental – continental collisions.the result is the collision between the two continents, which causes the formation of complex mountains such as the himalayas in south asia
Volcanic island arcs are associated with what type of plate boundary?
result if convergent boundary.(when two oceanic slabs converge, one descends beneath the other.this causes volcanic activity similar to what occurs at an ocean-continental boundary.the volcanoes form on the ocean floor instead of a continent.this newly formed land consists of and arc- shaped chain of small volcanic islands called a volcanic island arc. ex: aleutian islands off the shore of alaska
According to the property of paleomagnetism, rocks formed millions of years ago thus show the location of the magnetic poles at the same time of their formation
How does the age of seafloor sediments change with increasing distance from the ocean ridge?
when the oldest sediment from each drill site was plotted against its distance from the ridge crest,it was revealed that the age of the sediment increased with increasing distance from the ridge
The thermal convection that drives plate motion is caused by..
unequal distribution of earths heat
Be sure to define each of the following and know for the test
a.diverent-also called spreading centers occur when two plats ,move apart.this process results in upwelling of material from the mantle to create new seafloor.
Hot spots- concentration of heat in the mantle capable of producing magma, which rises to earths surface.the pacific plate moves over a hot spot, producing the hawaiian islands
lithosphere-rigid outer layer of earth, including the crust and upper mantle
pangaea-the proposed supercontinent that 200 my began to break apart and form the present land masses
plate tectonics- the theory that proposes that earths outer shell consisits of individual paltes that interact in various ways and thereby produce earhtquakes, volcanoes, mountains, and the crust itself
plates on earth-7 major plates( north american, south american, pacific, african eurasian,australian-indian, antartic)
sea floor spreading-is produced by divergant boundaries
What features are common at convergent continental boundaries?
give an example the result is a collision between the two continents, which causes the formation of complex mountains such as the himalayas in south asia
What are the three main types of plate boundaries?
transform fault boundary
List the lines of evidence that support the theory of plate tectonics..
earthquake patterns
ocean drilling
hot spots