Guided Notes
Geologic History
Relative Age
Sequence of Events
Correlation Techniques
Volcanic Ash Markers
Index Fossils
Geologic Time Scale
Evolution
Radioactive Dating
8. What are major events that have occurred on Earth?
▪ Earth formed about 4.6 billion years ago.
▪ Geologic time scale: geologists have
subdivided geologic time into units based on
fossil evidence.
o Fossil: any evidence of former life
▪ See ESRT pages 8-9 for specific geologic
history of New York State!
Units of Time: Largest
Time scale in
millions of years
Today
Split into 3 eras.
Note that each is
magnified to show
all of the things
that happened.
Formation of
Earth
to
Smallest
8. What are major events that have occurred on Earth?
Four Major Divisions of Time:
1. Precambrian Eon: represents the first 88%
of Earth history.
• No fossils because organisms were small and
soft & because most rocks were not
sedimentary.
Precambrian Eon
8. What are major events that have occurred on Earth?
2. Paleozoic Era: 7% of Earth’s history
• Invertebrates, fishes, amphibians, vertebrate,
land plants, and land animals all appear.
Paleozoic Era
8. What are major events that have occurred on Earth?
3. Mesozoic Era: 4% of Earth history.
• Evidence of dinosaurs, early birds, and early
mammals
Mesozoic Era
8. What are major events that have occurred on Earth?
4. Cenozoic Era: Most recent 1% of Earth
history.
• Fossils of modern plants and mammals
• Humans: Humanoids showed up late in the
Cenozoic era and have existed for about
0.04% of Earth’s history.
Cenozoic Era
8. What are major events that have occurred on Earth?
Summary:
1. Life has not existed for most of
Earth’s history.
2. Fossils provide evidence of
evolution.
3. Humans are very “new” to Earth.
8. What are major events that have occurred on Earth?
Cenozoic
ic
ozo ic
Mes
zo
leo
Pa
Complete
the pie
graph to
show the
amount of
Earth’s
history
each time
unit took.
Precambrian
Units of Time: Largest
Time scale in
millions of years
to
Smallest
Information about
species living at different
times.
If there is no line, there
is no rock record from
that time in New York.
Index fossils that
are found in New
York State
Mountain building (orogeny)
and rock forming events.
Bars have organism
group names. The
beginning of the bar
shows when the group
came into existence. The
end of the bar is when
the group went extinct.
The letters on the bars
represent the time of the
index fossils at the
bottom of the page.
How the continents
have moved
Use both pages together to determine when different events occurred.
✓ Checkpoint – Geologic History & the ESRT: Use your knowledge of Earth
Science and the Earth Science Reference Tables (pages 8/9, 2, and 3) to
answer the questions below.
Use your ESRT to fill in the table below for the three index fossils pictured.
!
Identification Letter
Fossil Name
Organism Group
Eon
Era
Period
Epoch
Important Geologic Event at
this Time
NYS Landscape Region
They May Be Found
!
!
Use both pages together to determine when different events occurred.
© K. Coder 2015
© K. Coder 2015
✓ Checkpoint – Geologic History & the ESRT: Use your knowledge of Earth
Science and the Earth Science Reference Tables (pages 8/9, 2, and 3) to
answer the questions below.
Use your ESRT to fill in the table below for the three index fossils pictured.
!
Identification Letter
L
Fossil Name
Coelphysis
Organism Group
Dinosaurs
Eon
Phanerozoic
Era
Mesozoic
Period
Triassic
Epoch
Late
Important Geologic Event at
this Time
Pangaea begins to
break up
NYS Landscape Region
They May Be Found
Newark Lowlands
!
!
✓ Checkpoint – Geologic History &
the ESRT
2) What are two characteristics of index fossils
that make it important in determining the age of
rocks?
✓ Checkpoint – Geologic History &
the ESRT
3) What was another method discussed (very
similar to index fossils) that helps geologists
determine the age of rocks?