Science Chapter Ten Section 1
Terms in this set (20)
The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations.
A long, undersea mountain chain that has a steep, narrow valley at its center, that forms as magma rises from the asthenosphere, and that creates how oceanic lithosphere (sea floor) as tectonic plates move apart.
The process by which new oceanic lithosphere (sea floor) forms as magma rises to earth's surface and solidifies at mid-ocean ridge.
The study of the alignment if magnetic minerals in rock, specifically as it relates to the reversal of earth's magnetic poles; also the magnetic properties that rock acquires during formation.
Who obtained new information about the continents and their coastlines 400 years ago?
New explorers that sailed te oceans of the world.
What did people notice when they studied new world maps 400 years ago?
They noticed that the coastlines of the continents on each side of the Atlantic Ocean were similar.
Who proposes the hypothesis of continental drift?
What is a supercontinent?
A supercontinent is a single landmass that contained all the continents.
When did Wegener thing that the small continents began forming?
250 million years ago.
Why was Wegener interested in finding fossils of the same plants and animals on two different continents?
He reasoned that if the connivers had once been joined, fossils of the same plants and animals should be found in areas that had once been connected.
What fossil was found in South America and Western Africa?
How did the ages and types of rocks found in some coastal areas of Africa and South America support wegener's hypothesis?
The ages of the rocks are the same, that at one time, the mountain ranges were close to one another.
How did the locations of mountain chains support wegener's hypothesis?
Mountain chains that ended at the coastline of one continent seemed to continue on other continents across the ocean.
Why was wegener's theory not proven in his lifetime?
His idea was easily disproved by geologic evidence.
Where did the evidence needed to support wegener's hypothesis come from two decades after his death?
The ocean floor
The sediment that covers the sea floor is ..... Closer to a ridge than it is farther from the ridge.
How old are the oldest ocean rocks?
175 million years old.
Describe the process of sea floor spreading.
The new ocean lithosphere (sea floor) rises to the earth's surface and solidifies at the mid-ocean ridge.
As magma solidifies to form _____, ____ -rich minerals in the magma align with earth's _____ field in the same way that a compass needle does.
New rock, iron, magnetic.
When the rock ____, the magnetic orientation of thein