fossils
Relative
age of
rocks
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Radioactive Geological
dating
time scale
Early
Earth
Question 1 - 10
• are the preserved remains or
traces of living things.
Answer 1 – 10
•fossils
Question 1 - 20
• Fossils provide evidence of
Answer 1 – 20
•how life has changed
over time
Question 1 - 30
• a hollow area in sediment in the
shape of or part of an organism.
Answer 1 – 30
• mold
Question 1 - 40
• evidence of the history of life and
past environments on Earth is
called
Answer 1 – 40
• The fossil record
Question 1 - 50
• List the steps of how fossils are
most commonly formed
Answer 1 – 50
• Organism dies
• Organism is buried by sediment
• Sediment hardens and preserves fossil
Question 2 - 10
• The number of years since the
rock formed
Answer 2 – 10
• absolute age
Question 2 - 20
• In horizontal sedimentary rocks,
the oldest layer is at the bottom
and the newest layer is on the
top and determines the relative
ages of rocks
Answer 2 – 20
• The Law of Superposition
Question 2 - 30
• the surface where new rock
meets up with a much older
rock surface.
Answer 2 – 30
• Unconformity
Question 2 - 40
• What is an index fossil?
Answer 2 – 40
• A fossil that is widely
distributed and represents
a type of organism that
only existed briefly
Question 2 - 50
• Index fossils are useful because-
Answer 2 – 50
• tell the relative ages of
rock layers by how they
occur
Question 3 - 10
• As elements break down over
time they release particles and
energy in a process called
Answer 3 – 10
• radioactive decay
Question 3 - 20
• How fast or slow the radioactive
elements decay is always
constant (never changing) and
the rate of decay is called
Answer 3 – 20
• half-life
Question 3 - 30
• Very useful in dating rocks
because it has a long half-life
Answer 3 – 30
• Potassium-Argon Dating
Question 3 - 40
• When carbon-14 is left in an
organism, scientists measure this
amount that is left to find
absolute age. Is the carbon-14
the radioactive element or the
new element formed?
Answer 3 – 40
• radioactive
Question 3 - 50
•Why is Radioactive
dating is good for
igneous rocks but not
sedimentary rocks
Answer 3 – 50
• Scientists can date particles
but not layers in sedimentary
rocks.
• Scientists can only date solid
rocks.
Question 4 - 10
• a record of the life forms and
geologic events in Earth’s history
Answer 4 – 10
• geological time scale
Question 4 - 20
• After Precambrian Time, basic
units of the GTS are
Answer 4 – 20
• eras and periods
Question 4 - 30
• three long units of time from
Precambrian Time to the present,
Ex: The Paleozoic, Mesozoic, and
Cenozoic
Answer 4 – 30
• Eras
Question 4 - 40
• Later,
_________________________
determined absolute age of
divisions in the GTS
Answer 4 – 40
• radioactive dating
Question 4 - 50
• What happened during the
Precambrian time period?
Answer 4 – 50
• 1st oceans, atmospheres,
landforms, and single-celled
organisms.
Question 5 - 10
• Scientists hypothesize that the
Earth formed at the same time
as other planets and the sun at
what time?
Answer 5 – 10
• about 4.6 billion years ago
Question 5 - 20
• Earth started as a ball of
Answer 5 – 20
• dust, rock, and ice in space
Question 5 - 30
• As Earth cooled, water vapor condensed
forming rain, accumulating to form
Answer 5 – 30
• The oceans
Question 5 - 40
• Without earth’s earliest life
forms we would have no…
Answer 5 – 40
• Oxygen/ozone
Question 5 - 50
• How did the earth take shape?
Answer 5 – 50
• Gravity pulled the mass together and
thermal energy heated up the earth.