4. Earth and Life Science
• Module 6: The geologic time
scale
• Instructress: Ms. Rizza L.
Baluyut
5.
6.
7.
8. • In todays discussion it makes you imagine and look back at
the history of the Earth from the beginning to the present.
As if you are watching a movie that shows pictures on how
Earth looked like billion years ago. Fast-forwarding, you see
so many extraordinary changes. In the beginning, there was
no life on Earth. As many years went by, living things existed,
grew, flourished, and even contributed to more changes in
our planet.
9.
10.
11.
12.
13. • At present, the Geologic Time Scale is divided into
big portions of time known as EONS. Eons are
further divided into ERAS. Eras are divided into
PERIODS. The Precambrian Eon is the point of time
in which our planet started to form.
• During this time, there was no formation of any
organism. What are evident are the abiotic features
of the earth
14. •It represents more than 80
percent of the total records
of geologic time and
supported with pieces of
evidence found in rocks.
During the Phanerozoic Eon,
living organisms like plants
and animals existed.
19. PRECAMBRIAN EON
•Oldest and longest time period
•From beginning of earth (4.5 billion
years ago) to 540 million years ago
•Oldest rocks are the deepest rocks
•ORES are deposited
(iron,silver,gold)
71. Geological hazard
•It is a geological and environmental process. It
includes earthquakes, landslides, floods, volcanic
eruptions. It is responsible for the deaths of
many people, damage to properties, and
destruction to our environment. In the past
years, millions of people died because of this
phenomenon.
72. RA 10121
• Also known as Philippine Disaster Risk Reduction and
Management Act, hazard is a dangerous natural
phenomenon, substance, human activity or condition that
may cause loss of life, injury or other impacts, property
damage, loss of livelihoods and services, social and
economic disruptions or environmental damage.
Infrastructures, public or private facilities, households,
transportation, and humans are the elements exposed to
these hazards.
73.
74. Pyroclastic Flow and Surges
•A mixture of ash, rock fragments
and gas materials that leave
devastating effects on the area
in which they flow.
78. Lahar
•It is a mudflow from a mixture
of volcanic water and rock
fragments. It moves down the
slopes of the volcano into the
surrounding area and
destroying everything on its
way.
79.
80. Volcanic Gases
•Gases present in toxic amount
trapped in cavities in volcanic rocks
dissolved in magma or lava or
through groundwater and is heated
by volcanic activity.
81.
82. Ash Falls
•These are ashes produced during a volcanic
eruption. It can destroy vegetation,
malfunctions engine; collapse roofs, and
endanger health of people. Ash fall
continues even after the explosion and can
affect the neighboring areas.
83.
84. Tsunamis
•These are substantial sea waves that occur
when an underwater volcano erupts. Its
wave height could be higher than 5 meters.
It can cause the death of humans, animals,
and destruction of infrastructures or
properties when it hits offshore.
85.
86. Liquefaction
•The strength and hardness of the
soil are reduced. It happens when
the groundwater mixed with ground
soil that makes the soil less stable.
87.
88. Ground subsidence
• Grounds sink due to earthquake
•
• Landslide is a geological hazard that includes movement of any
debris, masses of rock, or soil down a slope. It can occur in the
offshore and coastal environment but composed of a weak
strength of soil resting on a steep slope. Landslides hazards are
falling debris from a steep slope, pieces of rocks fall, and
mudflow. Human activities like mining, deforestation, quarrying,
digging, and conversion of land to residential or industrial areas
contribute to this natural phenomenon.
