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Chapter 4: Plate Tectonics
Terms in this set (32)
when earthquake occur, these happen; Geologists record them and study how they travel through the earth.
results from a force pressing on an area
a layer of rock that forms the earth's outer skin
a layer of hot rock that solid
upper most part of the mantle and the crust form this rigid layer
just beneath the lithosphere; hot and soft like silly puddy, but if you kicked it, you would stub your toe
made mostly of the metals iron and nickel and consists of two parts: a liquid outer core and solid inner core
a layer of molten metal that surrounds the inner core
a dense ball of solid metal; extreme pressure squeezes the atoms of iron and nickel so much that they cannot spread out and become a liquid
Wegener's idea that the continents were at one time a single land mass and have slowly drifted apart
300 million years ago, continents drifted together to form a this super-continent. Over tens of millions of years, the continents slowly moved toward their present day location
any trace of an ancient organism that has been preserved in rock
an undersea mountain chain that is part of a long system of mountains that wind beneath earth's oceans
a device that bounces sound waves off under water objects and then records the echos of the sound waves
it spreads apart along both sides of a mid-ocean ridge as a new crust is added. The ocean floor moves like a conveyer belt carrying the continents along with them.
when the ocean floor sinks beneath deep under water canyons
the process by which the ocean floor sinks beneath a deep ocean trench and back into the mantle
the lithosphere is broken into separate sections called
explains the formation, movement, and subduction of earth's plates
breaks of the earth's crust where rocks have slipped past each other
the place where two plates move apart
when a spreading boundary develops on land, two of earth's plates slide apart
two plates come together, or collide
a place where two plates slip past each other, moving in opposite directions
What are three types of plate boundaries?
What is the evidence for sea-floor spreading?
1. eruptions of molten material
2. magnetic stripes in the rock of the ocean floor
3. ages of the rocks themselves
What happens during deep-ocean trenches?
taking tens of millions of years, part of the ocean floor sinks back into the mantle
What was Wegener's hypothesis about the continents?
all the continents were once joined together in a single land mass and have since drifted apart
What evidence supported Wegener's hypothesis?
gathered evidence from different scientific fields to support his ideas about continental drift; studied land features, fossils, and evidence of climate change
Why was Wegener's hypothesis rejected?
he could not provide a satisfactory explanation for the force that pushes or pulls the continents
How have geologists learned about earth's inner structure?
used two main types of evidence about earth's interior: direct evidence from rock samples and indirect evidence from seismic waves
What are the characteristics of earth's crust mantel and core?
These layers vary greatly in size, composition, temperature, and pressure