I believe that the more you know about the past, the better you are prepared for the future. -Theodore roosevelt

3. I believe that the more you know about
the past, the better you are prepared for
the future.

6. The major assumption of Geology
Events of the past occurred the same way that they
are occurring today.

7. Used to determine whether an object or
event is older or younger than other
objects or events.
Tool: Sedimentary
rocks They are formed from the fragments of
other rock types.
New sedimentary rocks are flat.Fossils are deposited in these rocks

11. IDEA OF UNCONFORMITIES

12. Idea Of Unconformities

13. Used to measure the absolute age of an
object or event by analyzing isotopes of
radioactive elements.
Tool: Radioactive
IsotopesIsotopes-Atoms of the same element that
have similar # of p+ but different # of n⁰.
Unstable isotopes that break down stable
isotopes and/ or elements-Radioactive Decay

15. Time needed for half of a sample of a radioactive
substance to undergo radioactive decay.

16. PARENT ISOTOPE HALF- LIFE STABLE DAUGHTER
Uranium-235 704 million years Lead-207
Uranium-238 4.5 billion years Lead-206
Potassium-40 1.25 billion years Argon-40
Thorium-232 14.0 billion years Lead-208
Lutetium-176 35.9 billion years Hafnium-176
Rubidium-87 48.8 billion years Strontium-87
Samarium-147 106 billion years Neodymium-143

17. 1. An Ancient bone was
found and analyze. It
contain Potassium-40
that have decayed for
nearly 2 half- lives. How
old is the bone?
2. An igneous rock
contains ½ of its
original amount of
Potassium-40. how old
is the rock?
2.5 billion years 1.25 billion years
3. If Strontium-147
is cut into
pieces,what would
be the half- life of
each piece?

18. Indicates the life forms
present in different periods.
System used by scientists to relate stratigraphy
and time to any geologic events.

19. AGE-
EPOCH-
PERIOD-
ERA-
EON-

20. GEOLOGIC TIME SCALE (GTS) BOOK PAGE
64
EON ERA PERIOD EPOCH AGE
PHANEROIC
CENOZOIC
QUATERNARY
HOLOCENE 0.1
PLEISTOCENE 1.8
TERTIARY
PLIOCENE 5.3
MIOCENE 23.0
OLIGOCENE 33.9
EOCENE 55.8
PALEOCENE 65.5
MESOZOIC
CRETACEOUS 145
JURASSIC 200
TRIASSIC 251
PALEOZOIC
PERMIAN 299
PENNSYLVANIAN 318
MISSISSIPPIAN 359
DEVONIAN 416
SILURIAN 444
ORDOVICIAN 488
CAMBRIAN 542
PRECAMBRIAN
PROTEROZOIC BACTERIA & BLUE-GREEN ALGAE 2500
ARCHEAN OLDEST FOSSILS 3800

21. Precambrian is roughly 4.1 billion
years ago were 88% of the Earth’
history happened.
 The perceived harshness of the
primordial Earth happened during
Hadean(chaotic eon)-
bombardment of meteorites and
severe volcanic activities.
During this era, ocean and
atmosphere were formed. The
crust and core was also stabilized.

22. Archean was when the
Earth became warm but
the atmosphere contain
only methane with little to
no oxygen (orange
atmosphere).
 Most of Earth was still
covered with water.
Oceans were green due
to abundance of iron and
stromatolites.

23. Proterozoic era was when the
atmosphere began to have
oxygen, eukaryotes diversified,
multicellular animals spread and
continents began to drift away.
Paleozoic era was when fossils
of marine invertebrates(trilobites
and brachiopods) were formed in
sedimentary layers.

24. During the middle
Paleozoic era, marine life
forms developed shells.
During the Devonian
period, animals began to
breathe air as amphibians
came out of the sea and
land plants develop.
During the late Paleozoic
era, reptiles appear were
they lay eggs on the
ground.
Coal deposits

25. Mesozoic era marks the break up of major land masses.
Largest creatures were believed to appear in this era which are
descendants of reptiles in the Paleozoic era (dinosaurs)

26. Cenozoic era mountains were uplifted and new life forms
started to appear. Volcanic activities are wide spread, warm-
blooded animals like marsupials and mammals roamed on land.
Human left marks on land and stone tools were observed

27. OUTPUT: (by group)
Materials: illustration board,ruler, coloring
materials and design,GTS
Objective: create your own model of the
geologic time scale.