paleozoic plate tectonics

the paleozoic

The Paleozoic is the furthest back era of the Phanerozoic and it lasted the longest. But the Paleozoic was relatively recent, beginning only 570 million years ago. Compared with the long expanse of the Precambrian, the Phanerozoic is recent history. Much more geological evidence is available for scientists to study so the Phanerozoic is much better known. The Paleozoic begins and ends with a supercontinent. At the beginning of the Paleozoic, the supercontinent Rodinia began to split up. At the end, Pangaea came together.

pangaea

Pangaea was the last supercontinent on Earth. Evidence for the existence of Pangaea was what Alfred Wegener used to create his continental drift hypothesis, which was described in the chapter Plate Tectonics. As the continents move and the land masses change shape, the shape of the oceans changes too. During the time of Pangaea, about 250 million years ago, most of Earths water was collected in a huge ocean called Panthalassa (Figure 1.2). Click image to the left or use the URL below. URL:

formation of pangaea

A mountain-building event is called an orogeny. Orogenies take place over tens or hundreds of millions of years. As continents smash into microcontinents and island arcs collided, mountains rise. Geologists find evidence for the orogenies that took place while Pangaea was forming in many locations. For example, Laurentia collided with the Taconic Island Arc during the Taconic Orogeny (Figure 1.1). The remnants of this mountain range make up the Taconic Mountains in New York. The Taconic Orogeny is an example of a collision between a continent and a volcanic island arc. Laurentia experienced other orogenies as it merged with the northern continents. The southern continents came together to form Gondwana. When Laurentia and Gondwana collided to create Pangaea, the Appalachians rose. Geologists think they may once have been higher than the Himalayas are now.

textbook_image

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questions

the continents move around on earths surface but they are always centered near the equator.

-->  a) true

b) false

the phanerozoic

a) began with the supercontinent pangaea and ended with the supercontinent rodinia.

-->  b) was the first era to come after the precambrian.

c) was the second era of the phanerozoic.

d) all of these.

when continents converge to make a supercontinent

a) the convergent plate boundary goes from ocean-continent to continent-continent.

b) island arcs and microcontinents may also join in.

c) processes take place over tens or hundreds of millions of years.

-->  d) all of these.

this mountain range grew much higher when gondwana and laurentia collided to create pangaea.

a) the cascades

b) the himalayas

c) the alps

-->  d) the appalachians

eastern north america has a sequence of metamorphic rock, metamorphosed sedimentary rock and a volcanic arc. this is due to

-->  a) convergence during the taconic orogeny.

b) convergence due to the appalachian orogeny.

c) divergence due to the opening of the atlantic ocean.

d) divergence during the laurentian orogeny.

the southern continents came together to form pangaea.

a) true

-->  b) false

pangaea was central to alfred wegeners continental drift hypothesis.

-->  a) true

b) false

geologists think that the himalayas are the tallest mountains in earth history.

c) true

d) false

at the end of the paleozoic, there was/were

a) one landmass, called rodinia, and one super ocean, called rodalassa.

b) two landmasses, laurentia and gondwana, and one super ocean, called panthalassa.

-->  c) one landmass, called pangaea, and one super ocean, called panthalassa.

d) none of these.

the remnants of the taconic mountain range are found in ___.

-->  a) new york

b) california

c) australia

d) africa

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