Download Chapter 6 The Rock And Fossil Record

 Uniformitarianism-
Principle that states
that the same geological process
shaping the Earth today have been at
work throughout Earth’s history.
 Examples: “The present is the key of
the past” is a phrase that best
summarizes uniformitarianism.
 Catastrophism-
Principle that states that all
geological change occurs suddenly.
 Fact of Catastrophism: Supporters of
catastrophism claimed that the formation of
all Earth’s features, such as its mountains,
canyons, and seas, could be explained by
rare, sudden events called catastrophes.
 Relative
dating- determining whether an object
or event is older or younger than other objects
or events
 Superposition- principle that states that younger
rocks lie above older rocks in undisturbed
sequences.
 Facts of superposition: “ Younger over older” is
a phrase you can use to remember this principle.
 Geologic
Column: Ideal sequence of rock
layers that contains all the known fossils
and rock formations on Earth arranged
from oldest to youngest.
 Fact of geologic column: Geologists rely on
the geologic column to interpret rock
sequences.
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Unconformity- a surface that represents a missing part
of the geologic column.
Steps to unconformity:
Deposition in this low area occurs as sediment is
regularly supplied.
The sediment supply is cut off, and deposition stops.
Tectonic uplift exposes the area to erosion by water,
wind, or other elements.
Sediment is supplied again, and deposition resumes.
Eventually, the area is worn down enough for
deposition to start again.
A
fault and an intrusion are always
younger than the layers they cut across.
 Folding and tilting are events that are
always younger than the rock layers
they affect.
Folding
Faulting
 Tilting
 Intrusion
 These
pictures all came from Google
images.