The Geologic Time Scale powerpoint presentation.pptx

GEOLOGICAL
TIME SCALE
Home Contact Festival
EARTH SCIENCE

TABLE OF CONTENTS
EARTH SCIENCE
Measuring Geologic Time
Divisions of Geologic Time
Geologic Eras

LEARNING OBJECTIVES
AFTER COMPLETING THIS CHAPTER,
85% OF THE STUDENTS WILL ABLE TO:
EARTH SCIENCE
a. describe the methods that
the scientists used to date
the age of rocks
b. name the four geologic
eras
c. identify the major life
forms and geologic events
that occurred in each of the
geologic eras

EARTH SCIENCE Home Contact Festival

EARTH SCIENCE
MEASURING
GEOLOGIC TIME

GEOLOGIC TIME
THE VERY LONG
PERIOD OF TIME
DURING WHICH
THE EARTH HAS
EXISTED.
EARTH SCIENCE

SCIENTISTS USE
THE RELATIVE AGE
AND ABSOLUTE
AGE OF ROCKS AND
FOSSILS TO
MEASURE
GEOLOGIC TIME.
EARTH SCIENCE

THE METHODS USED
TO FIND THE
RELATIVE AGES OF
ROCKS AND FOSSILS
ARE NOT VERY
USEFUL FOR
FINDING ABSOLUTE
AGE.
EARTH SCIENCE

1. LAW OF
SUPERPOSITION
STATES THAT OLDER
ROCKS ARE
GENERALLY FOUND
UNDER YOUNGER
ROCKS.
EARTH SCIENCE

RATE OF EROSION
EARTH SCIENCE
Scientists tried to figure out
the rate of erosion to help
determine the length of
geologic time.
Erosion is the gradual wearing
away or movement of soil,
rock, or other materials by
natural forces like water, wind,
or ice.
EROSION

EARTH SCIENCE
Scientists determined that erosion
occurs at an average rate of about one-
third of a meter every 5,000 years.
or ice.
EROSION

EARTH SCIENCE
Using the rate of erosion method,
scientists estimated that the Grand
Canyon was about 30 million years old.
or ice.
EROSION

EARTH SCIENCE
Unfortunately, the rate of erosion is not
always the same, so the scientists'
estimates were not accurate.
or ice.
EROSION

EARTH SCIENCE
RATE OF SEDIMENTATION
Another method
scientists used to
determine the length of
geologic time was to
measure the amount of
sediment deposited.

EARTH SCIENCE
Many factors affect
the rate of sediment
deposition.
-size of the river
-speed of the river

EARTH SCIENCE
Another problem with the
sedimentation method is
that the thickness of a
sediment deposit is not
always an accurate
measure of the amount of
sediment in each layer.

EARTH SCIENCE
The lower layers of
a sediment deposit
are packed down as
other sediments are
deposited on top.

RADIOACTIVE DECAY
EARTH SCIENCE
In 1896, Antoine
Henri Becquerel
discovered
radioactivity in
uranium.

RADIOACTIVE DECAY
EARTH SCIENCE
Becquerel found that
when he exposed
photographic paper to
uranium an image
appeared on the
paper.

RADIOACTIVE DECAY
EARTH SCIENCE
He concluded that a
form of energy from
the uranium caused
the image to appear.

MARIE CURIE

PIERRE CURIE

RADIOACTIVE DECAY
EARTH SCIENCE
In their studies of
uranium, the Curies
discovered that the
nuclei of some
radioactive elements
decay, or break apart.

RADIOACTIVE DECAY
EARTH SCIENCE
A decay element is
the stable element
into which a
radioactive element
breaks down.

RADIOACTIVE DECAY
EARTH SCIENCE
During radioactive
decay, the small
particles that make
up the nucleus of an
atom break apart.

RADIOACTIVE DECAY
EARTH SCIENCE
When the nucleus
of an atom breaks
apart, energy is
released in the form
of gamma rays.

RADIOACTIVE DECAY
EARTH SCIENCE
Half-life is the
rate at which
radioactive
material decays is
constant.

RADIOACTIVE DECAY
EARTH SCIENCE
For example, if you began
with a kilogram of
radioactive material, half
of the kilogram would
decay after one half-life.
Half of the remaining
material would decay in
another half-life.

RADIOACTIVE DATING
EARTH SCIENCE
Using radioactive
elements in rocks
or fossils, scientists
can find the
absolute age of the
rocks or fossils.

RADIOACTIVE DECAY
EARTH SCIENCE
For example, suppose a
radioactive element had a
half-life of one million years.
If you found a rock that
contained equal amounts of
the radioactive element and
the decay element, the rock
would be about one million
years old.

RADIOACTIVE DECAY
EARTH SCIENCE
Many different
radioactive
elements are
used to date
rocks and fossils.

RADIOACTIVE DECAY
EARTH SCIENCE
Another
radioactive
element used for
dating is uranium
238.

RADIOACTIVE DECAY
EARTH SCIENCE
The Age of the Earth
Scientists have used
radioactive dating to
help them determine
the ages of rocks.

RADIOACTIVE DECAY
EARTH SCIENCE
Scientists have
found some rocks
in South Africa that
are more than 4
billion years old.

RADIOACTIVE DECAY
EARTH SCIENCE
Rocks found in
Greenland have
been found to be
3.95 billion years
old.

RADIOACTIVE DECAY
EARTH SCIENCE
Rocks ranging in
age from 3.0 to 3.6
billion years have
been found in the
state of Minnesota
and in parts of
Russia.

RADIOACTIVE DECAY
EARTH SCIENCE
Radioactive dating of
moon rocks brought
back by the Apollo
missions show them
to be 4.0 to 4.6 billion
years old.

RADIOACTIVE DECAY
EARTH SCIENCE
The oldest rocks
brought back from
the moon are more
than one-half billion
years older than the
oldest earth rocks.

EARTH SCIENCE
DIVISIONS OF
GEOLOGIC TIME

FOUR
GEOLOGIC ERAS
EARTH SCIENCE

PRECAMBRIAN
ERA
EARTH SCIENCE

PALEOZOIC
ERA
EARTH SCIENCE

PRECAMBRIAN
ERA
PALEOZOIC ERA
MESOZOIC ERA
CENOZOIC ERA
EARTH SCIENCE

PRECAMBRIAN ERA
EARTH SCIENCE
The earliest
time period.

PRECAMBRIAN ERA
EARTH SCIENCE
However, some
scientists think that
the Precambrian
Era should be
divided into
different eras.

PRECAMBRIAN ERA
EARTH SCIENCE
Many scientists
disagree about
the events that
occurred during
this time.

PALEOZOIC ERA
EARTH SCIENCE
It began approximately
600 million years ago.
MESOZOIC ERA
It began about 230 million
years ago.

EARTH SCIENCE
CENOSOZOIC ERA
It began about 230
million years ago.
Scientists do not
know when the
Cenozoic Era will
end and a new era
will begin.

PRECAMBRIAN ERA
EARTH SCIENCE
is divided into smaller
divisions called periods.
CENOZOIC ERA
is further divided into
divisions called
epochs.

EARTH SCIENCE
THE DIVISION OF
GEOLOGIC TIME
INTO ERAS, PERIODS,
AND EPOCHS IS
BASED ON CHANGES
THAT OCCURRED ON
THE EARTH.

EARTH SCIENCE
THE EXTINCTION OF TRILOBITES IS
ONE CHANGE THAT SEPARATES THE
PALEOZOIC ERA FROM THE
MESOZOIC ERA.
ORGANIC CHANGES

EARTH SCIENCE
THE MELTING OF A WORLDWIDE ICE CAP IS
ONE CHANGE THAT SEPARATES
PRECAMBRIAN TIME FROM THE PALEOZOIC
ERA.
INORGANIC CHANGES

EARTH SCIENCE
PERIODS OF MOUNTAIN
BUILDING ALSO SEPARATE TIME
PERIODS.
INORGANIC CHANGES

EARTH SCIENCE
GEOLOGIC
ERAS

EARTH SCIENCE
GEOLOGIC ERAS
The earth's four geologic eras
were of different lengths.
PRECAMBRIAN
ERA
MESOZOIC
ERA
PALEOZOIC
ERA
87% 8%
3.5% 1.5%
CENOZOIC
ERA

EARTH SCIENCE
PRECAMBRIAN ERA
 Precambrian Time was the
longest geologic era.
PRECAMBRIAN
ERA
87%
ANOMALOCARIS
(UNUSUAL SHRIMP)
PIKAIA
DIVIDED INTO THREE EONS:
 Hadean Eon
 Archean Eon
 Proterozoic Eon

EARTH SCIENCE
PRECAMBRIAN ERA
PRECAMBRIAN
ERA
87%
EARTH
MOON
 HADEAN EON (occurred 4.6 to
4 billion years ago)
 It is named for the
mythological Hades, an allusion
to the probable conditions of this
time.

EARTH SCIENCE
PRECAMBRIAN ERA
PRECAMBRIAN
ERA
87%
EARTH
MOON
 During the Hadean time,
solar system was forming
within a cloud of dust and gas
known as the solar nebula,
which eventually spawned
asteroids, comets, moons and
planets.

EARTH SCIENCE
PRECAMBRIAN ERA
PRECAMBRIAN
ERA
87%
PRECAMBRIAN SHIELD
SHIELD
 ARCHEAN EON (between about 4.0
and 2.5 billion years ago)
 continental shield rock began to
form and approximately 70% of
continental landmass was formed
during this time.

EARTH SCIENCE
PRECAMBRIAN ERA
PRECAMBRIAN
ERA
87%
PRECAMBRIAN SHIELD
SHIELD
 Continent is a large landmass
and shield are areas of
Precambrian rocks.
 By the end of the Archean eon,
the ocean floor was covered in a
living mat of bacterial.

EARTH SCIENCE
PRECAMBRIAN ERA
PRECAMBRIAN
ERA
87%
FOSSIL OF A JELLYFISH
FOSSILS OF
BACTERIA
 PROTEROZOIC EON
(about 2.5- 541 billion years ago)
enough shield rock had formed to
start a recognizable geologic
processes such as plate tectonics.

EARTH SCIENCE
PRECAMBRIAN ERA
PRECAMBRIAN
ERA
87%
FOSSILS OF
BACTERIA
 During this time, geology was
about to be joined by biology to
continue Earth’s progress from a
molten hell to a living planet.

EARTH SCIENCE
PRECAMBRIAN ERA
 It is generally accepted that
different types of prokaryotic
organisms formed symbiotic
relationships.
PRECAMBRIAN
ERA
87%
FOSSILS OF
BACTERIA
Scientists have found very few
fossils from Precambrian Time.
However, they have found some
fossils of simple marine, or ocean
organisms.

EARTH SCIENCE
PRECAMBRIAN ERA
These fossils include mostly
small, soft-tissued organisms
such as jellyfish and primitive
worms. Fossils of bacteria,
algae, and fungi have also
been found.
PRECAMBRIAN
ERA
87%
FOSSILS OF
BACTERIA

EARTH SCIENCE
PRECAMBRIAN ERA
 CAMBRIAN EXPLOSION was the
event that ended the
Precambrian Era.
PRECAMBRIAN
ERA
87%
FOSSILS OF
BACTERIA
 This event appears in the fossil
record around 542 million years
ago and lasts approximately 40
million years.

EARTH SCIENCE
PALEOZOIC ERA
 Paleozoic Era, many changes took
place on the earth's surface.
PALEOZOIC ERA
8%
TRILOBITES
BRACHIOPOD
Fossils of many different kinds of
plants and animals have been
found. The most common life
forms early in this era were
invertebrates (in-VER-to-brāts).

EARTH SCIENCE
PALEOZOIC ERA
 Invertebrates are animals without
backbones. Marine invertebrates
called trilobites were very numerous
early in the Paleozoic era.
PALEOZOIC ERA
8%
TRILOBITES
BRACHIOPOD

EARTH SCIENCE
PALEOZOIC ERA
 The era has been divided into six
periods:
PALEOZOIC ERA
8%
TRILOBITES
BRACHIOPOD
1. Cambrian Period
2. Ordovician Period
3. Devonian Period
4. Silurian Period
5. Carboniferous Period
6. Permian Period

EARTH SCIENCE
PALEOZOIC ERA
CAMBRIAN PERIOD (544- 505 MYA)
PALEOZOIC ERA
8%
TRILOBITES
FOSSILS OF
SPONGES
Following the Precambrian mass
extinction, there was an explosion
of new kinds of organisms in the
Cambrian.

EARTH SCIENCE
PALEOZOIC ERA
 many types of primitive animal
called sponges evolved.
PALEOZOIC ERA
8%
TRILOBITES
FOSSILS OF
SPONGES
 Small ocean invertebrates
(animal without backbone) called
trilobites, were very abundant.

EARTH SCIENCE
PALEOZOIC ERA
ORDOVICIAN PERIOD (505- 440 MYA)
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND
 The oceans were filled with
invertebrates on many types.
 first fish evolved

EARTH SCIENCE
PALEOZOIC ERA
 plants colonized the land for
the first time, but animals still
remained in the water.
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND

EARTH SCIENCE
PALEOZOIC ERA
SILURIAN PERIOD(440- 410 MYA)
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND
 In the oceans, corals appeared
and fish continued to evolved.

EARTH SCIENCE
PALEOZOIC ERA
 On land, vascular plants appeared
with special tissues to circulate water
and other materials, they could grow
larger than earlier, non vascular
plants.
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND

EARTH SCIENCE
PALEOZOIC ERA
 DEVONIAN PERIOD (410- 360 MYA)
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND
 The first seed plants evolved. Seeds
had a protective coat and stored food
to help them survive.

EARTH SCIENCE
PALEOZOIC ERA
 Seed plants eventually became
the most common type of land
plants.
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND

EARTH SCIENCE
PALEOZOIC ERA
PALEOZOIC ERA
8%
FIRST FISH
PLANTS ON LAND
 Fish with lobe fins evolved. They
could breathe air when they
raised their heads above water.
Breathing would be necessary for
animals to colonized the land.

EARTH SCIENCE
PALEOZOIC ERA
 CARBONIFEROUS PERIOD (360-290 MYA
PALEOZOIC ERA
8%
ICHTHYOSTEGA
HYLONOMUS
 widespread forest of huge plants
left massive deposits of carbon
that eventually turned to coal.

EARTH SCIENCE
PALEOZOIC ERA
 The first amphibian evolved to
colonize land, but hey had to return
to the water to reproduce.
PALEOZOIC ERA
8%
ICHTHYOSTEGA
HYLONOMUS
 Soon after amphibians arose, the
first reptiles evolved. They were
the first animals that could
reproduce on dry land.

EARTH SCIENCE
PALEOZOIC ERA
PERMIAN PERIOD (290-245 MYA)
PALEOZOIC ERA
8%
 All the major land masses
collided form a supercontinent
called pangaea.

EARTH SCIENCE
PALEOZOIC ERA
 Temperatures were extreme and
climate was dry.
PALEOZOIC ERA
8%
 Plants and animals evolved
adaptations to dryness, such as
waxy leaves or leathery skin to
prevent water loss.

EARTH SCIENCE
PALEOZOIC ERA
 THE END PERMIAN MASS EXTINCTION
EVENT ( THE GREAT DYING) marks the end
of the Paleozoic era. This extinction event
was so severe that it resulted in the loss
of about 90% of all the species on the
earth at the time
PALEOZOIC ERA
8%
 The Permian ended with a mass
extinction.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 During the Mesozoic Era, Pangaea
began to break apart.
MESOZOIC ERA
3.5%
Scientists believe that the expansion
of the sea floor along mid-ocean
ridges gradually spread the
continents apart.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 The Mesozoic Era is further
divided into three periods:
MESOZOIC ERA
3.5%
 TRIASSIC PERIOD
 JURASSIC PERIOD
 CRETACEOUS PERIOD

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 TRIASSIC PERIOD (251.9 to 201. 3 MYA)
MESOZOIC ERA
3.5%
 By the start, all the landmasses had
coalesced to form Pangaea (a
supercontinent shaped like a giant C
straddled the Equator and extended
toward the Poles.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 During the Triassic period, first
dinosaurs walked on the land, the
first pterosaurs sailed through the sky
and the first ichthyosaurs and
plesiosaurs swam in the oceans.
MESOZOIC ERA
3.5%

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 MASSIVE VOLCANIC ERUPTION from a
large region known as the Central
Atlantic Magmatic Province (CAMP)
spewed forth huge amounts of lava
and gas, including carbon dioxide,
sulfur and methane.
MESOZOIC ERA
3.5%

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 JURASSIC PERIOD (208 to 200 MYA)
MESOZOIC ERA
3.5%
 At the beginning the continent, PANGAEA,
split into two continents: LAURASIA AND
GONDWANA. This division opened up what
would eventually become the Gulf f Mexico
and the Atlantic Ocean.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 Dinosaurs continued as the
dominant species and evolved
gigantic.
MESOZOIC ERA
3.5%
 Near the end of the Jurassic period
several species died out giving rise to
the Cretaceous Period.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 CRETACIOUS PERIOD (145 to 66 MYA)
MESOZOIC ERA
3.5%
 During this period, oceans formed as
land shifted and broke out of one big
supercontinent into smaller ones.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 the first flowering plants (Angiosperm
appeared and rapidly diversified.
MESOZOIC ERA
3.5%
 Also, the Rocky Mountains began to
rise from the Cretaceous interior
Seaway.

EARTH SCIENCE
MESOZOIC ERA
(AGE OF REPTILES)
 The leading theory of what caused
Mesozoic era to end was that huge
asteroid or comet slammed into
Earth 65 million years ago, blocking
sunlight, changing the climate and
setting off global wildfires.
MESOZOIC ERA
3.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 The last and most recent of the
geologic periods. Its names means
“new life” coming fro the Greek root
kainos, meaning “new”, and zoic “life”.
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Invertebrates, fish, reptiles etc. were
essentially of modern types, but
mammals, birds, protozoa and
flowering pants still evolved and
developed during this period.
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 The Cenozoic Era is generally
divided into three periods:
CENOZOIC ERA
1.5%
 Paleogene
 Neogene
 Quaternary

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 TERTIARY PERIOD (65- 1.8 MYA)
CENOZOIC ERA
1.5%
 Earth’s climate was generally warm and
humid.
 Mammals evolved to fill virtually all
niches vacated by dinosaurs. Many
mammals increased in size.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Mammals called primates evolved,
including human ancestors
CENOZOIC ERA
1.5%
 flowering plants and insects were
numerous and widespread.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 TERTIARY PERIOD (65- 1.8 MYA)
CENOZOIC ERA
1.5%
 Tertiary period (also referred to as
the Paleogene and Neogene Period)
represent the first geological period
in the Cenozoic era.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 The tertiary period is generally
divided into 5 epochs namely:
 Paleocene
Eocene
Oligocene
 Miocene
 Pliocene
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Paleocene Epoch (65- 55.8 MYA)
CENOZOIC ERA
1.5%
 The Paleocene Epoch opens and
closes with major events in Earth’s
history and was a great time for
evolution and diversification.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Most striking features of this epoch
was the complete absence of
dinosaur and other reptilian groups
that were dominant during the
preceding Cretaceous period.
CENOZOIC ERA
1.5%
 rapid proliferation and evolution of
mammals.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Eocene Epoch (66- 33.9 MYA)
CENOZOIC ERA
1.5%
 marks the first appearance in the fossil record
of the two completely marine mammal groups,
the cetaceans (whales, porpoises, and
dolphins) and the sirenians (the modern
manatees and dugongs).

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 they also provides the first
elephant- like animals and the
early bats
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 one of the major events of this epoch
is the separation of Antarctica and
Australia created a deep water
passage that changed oceanic
circulation patterns and global heat
transport, resulting in a global cooling
event.
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
Oligocene Epoch 34-23 MYA)
CENOZOIC ERA
1.5%
 Major changes during this epoch
includes a global expansion of
grasslands, and a regression of
tropical broad leaf forests to
equatorial belt.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Climates appear to have been
temperate, and many regions
enjoyed subtropical climatic
conditions.
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
Miocene Epoch (23-5. 3 MYA)
CENOZOIC ERA
1.5%
 The Miocene saw a change in
global circulation patterns due to
slight position changes of the
continents and globally warmer
climates.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Kelp forest appeared for the first time
the , as did sea otters and critters
unique to those environment.
CENOZOIC ERA
1.5%
 Ocean- going mammals
Desmostylia went extinct

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Pliocene Epoch (5. 3-2.6 MYA)
CENOZOIC ERA
1.5%
 The Pliocene Epoch saw general
climatic cooling, with subtropical
regions retreating equatorially.
 Hominid Evolution
 Rise of Isthmus of Panama
 Rise of Himalayas

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Quaternary Period (1.8 MYA – to
Present)
CENOZOIC ERA
1.5%
 climates cooled, leading to a series
of ice ages. This created land bridges
between continents, allowing land
animals to move to new areas.

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Some mammals like wooly
mammoths shown here, adapted to
the cold by evolving very large size
and thick fur.
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
• Quaternary Period is divided into
2 epochs:
 Pleistocene
 Holocene
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Pleistocene
CENOZOIC ERA
1.5%
 known as the “Ice Age”
 climate cooled and ice sheets
began covering Earth’s
landmasses

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 among the better known animals
of the Pleistocene are
mammoths , giant ground sloth,
and saber tooth.
CENOZOIC ERA
1.5%

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 Holocene
CENOZOIC ERA
1.5%
 the most recent span of geologic
time

EARTH SCIENCE
CENOZOIC ERA
(AGE OF MAMMALS)
 marked climatic warming and the
disappearance of the continental
glaciers
CENOZOIC ERA
1.5%
 the disappearance of mammoths,
giant ground sloth and saber
tooth

THANK YOU
EARTH SCIENCE
For listening and
hope you learn
from us
End Of Slide

The Geologic Time Scale powerpoint presentation.pptx

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The Geologic Time Scale powerpoint presentation.pptx