Rock & Fossil Record
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Transcript of Rock & Fossil Record
ROCK & FOSSIL RECORD
What are igneous, sedimentary, and metamorphic rocks and which picture is a representation of that rock type.
A
B
C
TYPES OF ROCK Igneous -
think of the word “ignites” Formed from solidified molten rocks
Metamorphic – Think of the word “magma” Formed when other rocks are changed by heat, pressure, and
chemical reactions
Sedimentary - Formed when combinations of rock fragments, seashells, and
chemicals are composed in layers and hardens
THE EARTH’S STORY
Uniformitarianism
Theory: Geologic change is gradual
Scientist: Hutton
To help me remember:
think of uniform
Catasrophism
Theory: Geologic change is sudden
Scientist: Lyell
To help me remember:
Think of catastrophe (disaster)
CURRENT THEORY Modern geology (current theory):
Gradual geologic change is interrupted by catastrophes
To study geologic change involves studying past life. Using fossils to study past life is called paleontology.
RELATIVE DATING Relative Dating: what scientist use to
determine whether an event or object is older or younger than another event or object
____________ the order of events. There is no __________ information
What type of rock do you think contains relative age about events and objects in the Earth’s history? _____________________________
LAW OF SUPERPOSITION The Law of Superposition states:
Younger rock lies above older rock in an undisturbed sequence.
GEOLOGIC COLUMN Geologic column is an arrangement of
rock layers in which the older rocks are at the bottom
Geologic columns help scientist find the relative age of the Earth.
HOW GEOLOGIC COLUMNS ARE FORMED?
Stratigraphic sections are pieced together to from short columns Stratigraphic – layered rock
Short columns are pieced together to from longer columns
All columns are pieced together to form the entire Earth’s geologic column
CROSS CUTTING LAW Any feature that cuts across a body of
sediment or rock is younger than the body of sediment or rock that it cuts
SO WHAT ABOUT DISTURBED ROCK? Features:
Faults – break in the Earth’s crust, where blocks of crust shift past one another
FEATURES Intrusion – Igneous rock (molted rock)
from the Earth’s interior that squeezes into existing rock and cools (younger then sedimentary layers)
EVENTS Folding – Occurs when rock layers bend
and buckle from Earth’s internal forces
EVENTS Tilting -occurs when Earth’s forces
move rock layers until they become slanted.