ELS-Week-6-Day-2-Geologic-Timelinehagah.pdf

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1. GEOLOGIC

TIME & DATING
Earth and Life Science- WEEK 6 (Day 2)

2. Most Essential Learning
Competencies (MELCs)
1.Differentiate relative and absolute
dating through pictures presented.
2.Describe how relative and absolute
dating provides evidence of
geologic history.
3.Determine the guide fossils that are
used to define and identify
subdivisions of the geologic time
scale.

3. ACTIVITY
“Timeline Discovery”
Brainstorm what the images might represent and
how they relate to determining the age of Earth’s
features. Then, sort the pictures into two
categories: relative dating and absolute dating.

4. 1
2
3
4
5
6
7

6. Used to arrange
geological events and
the rock layers they
produce in a sequential
order
Qualitative method of
dating
Used stratigraphy method
(oldest found at the
bottom and youngest at
the top)
Relative Dating

7. Used absolute dating
methods, sometimes
called numerical dating,
to give rocks an actual
date, or date range, in
number of years
Quantitative method of
dating
Used radiometric method
by radioactive decay:
concept of isotopes and
concepts of half- life
Absolute Dating

8. Radioactivity remains unaffected by geological processes and is
easily measured in the lab. As rocks age, daughter isotopes
accumulate. Radioactive dating determines the absolute age of
rocks and minerals by measuring the ratio of parent to daughter
isotopes.

9. Stratigraphy is the science that
deals with characteristics of
layered rocks and how these
rocks are used to trace the history
of the earth.
Stratification is also known as
bedding, which is the layering
that happens in sedimentary and
igneous rocks formed at the
surface of the Earth that comes
from lava flows or other volcanic
activity.

10. Nicholas Steno
A Danish scientist who
studied the relative position
of sedimentary rocks as
early as mid 1600’s.
Sedimentary rocks are
formed particle by particle,
bed by bed, and the layers
are piled one on top of the
other.

11. Stratigraphic Laws
•are basic principles that all
geologists use in decoding or
deciphering the spatial and
temporal relationships of rock layers
•These includes the following:
1.Law of Superposition
2.Law of Inclusions
3.Law of Cross Cutting Relationship
4.Law of Original Horizontality
5.Law of Unconformities
6.Law of Faunal Succession

12. Law of Superposition
The largest and
heaviest rock
layer that
settled first at
the bottom is
the oldest rock
layer.

13. Law of Inclusions
It states that if a rock body (Rock B) contained
fragments of another rock (Rock A), it must be
younger than the fragments of rocks it contained.
The intruding rock (Rock A) must have been there
first to provide the fragments.
(ROCK A)
(ROCK B)

14. Law of Cross Cutting Relationship
When a fault or
dike- a slab rock
(magma) cuts or
intrude through
another rock,
that fault or
magma is
younger than the
rock.

16. Law of Original Horizontality
Layers (strata) are
deposited in nearly
horizontal layers.
Each new layers is
parallel to the Earth’s
surface is laid on top
of the older one.
Strata that are
folded have been
disturbed by an
earth event.
Any “sloping” of layers must
have occurred AFTER the
layers formed.

17. Law of Unconformities
describes a layer of
rock that have been
deformed or eroded
before another layer
is deposited, resulting
in rock layer
mismatching
Can be
disconformity;
angular
unconformity; and
non-conformity

18. Law of Unconformities
Disconformity: Exists between parallel layers of
sedimentary rocks where some layers have been
removed by erosion.
Angular Unconformity: Found where tilted or folded
sedimentary rocks are overlain by younger, more
horizontal layers.
Nonconformity: Occurs where sedimentary rocks lie on
top of an eroded surface of non-layered igneous or
metamorphic rocks.

19. Law of Faunal Succession
first recognized by William Smith
different strata contain particular assemblage of
fossils by which rocks may be identified and
correlated over long distances

20. Kinds of Fossils
Petrified: Minerals replace
the remains, turning them
into rock.
Mold: A hollow form left
after the contents dissolve
but the shell remains.
Cast: When a mold is filled
with minerals, creating a
replica of the original
organism

21. Have you experienced playing or
fitting cut out patterns or puzzle?

22. How do geologists
correlate rock layers?
Correlation is the process of
showing that rocks or
geologic events occurring
at different locations are of
the same age.
Geologists have developed
a system for correlating
rocks by looking for
similarities in composition
and rock layer sequences at
different locations.

23. Types of Correlation
1.Physical Correlation involves
identifying and classifying rock
layers based on criteria such as
color, texture, and mineral
content.
2.Fossil Correlation uses the unique
characteristics of fossils, like a
short geological lifespan and
distinct features, to estimate the
age of rock layers by matching
them with similar fossil-bearing
strata in other areas.

24. Methods in
Correlating Rock
Layers
1.Rock types and
its characteristics
2.Bed rock
3.Index fossil

25. Rock types and its
characteristics
color, texture, hardness,
composition or its mineral
content
the harder and more densely
packed the particles are, the
older the rock and the deeper
the layer it came from

26. Bed Rock
a deposit of solid rock
that is typically buried
beneath soil and other
broken or
unconsolidated
material (regolith)
serve as a reference
point, allowing
geologists to match
and compare layers
across different
locations, aiding in
understanding the
geological history

27. Index fossils
is also known as guide
fossils or indicator fossils
provide a time-specific
marker
fossils from species that
were widespread but
only existed for a short
period
use to identify and
match the age of rock
layers in different
locations, helping to
establish a timeline and
correlation between
those layers

28. Common Index Fossils
Ammonites
245 to 65 mya
Brachiopods
550 mya
Graptolites
540 to 505 mya
Trilobites
540 to 245 mya

29. How to match correlated rock layers?
Matching of rock layers may be determined by merely
looking at its features.
These three columns represent rock layers from three separate locations
or outcrops. Some columns may be missing layers due to erosion. No
single column represents a complete record.

30. How to match correlated rock layers?
Find one or more layers present in all columns that can
be matched like a puzzle.

31. After matching correlated rock layers, determine the relative age of
each layer according to the law of superposition.

32. After matching correlated rock layers, determine the relative age of
each layer according to the law of superposition.
Oldest Rock
Youngest Rock
Same Age
Same Age
Same Age
Same Age
Those rock layers having the
same composition, textures,
and fossil content were
considered as rock layers with
the same age.
1
2
3
4
5
6
7
8

33. Geologic Timeline
a system used by Earth scientists to
describe the timing and relationships of
events in Earth's history
Correlate rock units and divide them
into time units according to the
significant events in the history of Earth
such as the mass extinction of a large
population of fauna and flora
displayed in a chart with the oldest at
the bottom and the youngest at the
top

34. Geologic Time Scale Unit
Eons: The largest divisions, spanning billions of
years, marking major Earth changes like the
origin of life.
Eras: Lasting hundreds of millions of years,
defined by major events like mass extinctions.
Periods: Tens of millions of years, characterized
by significant developments in climate,
geography, and life forms.
Epochs: Lasting several million years, capturing
specific shifts like changes in climate and
species.
Ages: The smallest units, lasting millions of years
or less, representing detailed changes within
epochs.

38. Explain how relative and absolute
dating provides evidence for
understanding Earth's geologic
history.

39. Analyzing Rock Outcrops
Direction: The rock columns represent four widely separated
locations, W, X, Y, and Z. Number 1, 2, 3, and 4 represent fossils.
The rock layers have not been overturned.

40. Analyzing Rock Outcrops
Guide Questions:
1.Based on the correlation of fossils and rock
layers, determine the relative age of the
rock layers from oldest to youngest.
2.Which fossil indicates the oldest rock layer?
3.Which fossil indicates the youngest rock
layer?
4.Which numbered fossil best represents an
index fossil?

41. 1. Oldest to youngest
2.
3.
4.

42. Application Question:
Imagine you're a paleontologist
exploring rock layers in a national
park. You find different fossils in each
layer. How do these fossils help you
determine which rock layers are
oldest and which are youngest?
What do these findings reveal about
the area's geological history and the
types of organisms that lived there?

43. Home- Based Activity:
Igneous Rocks
Briefly answer the following questions in 2-4 sentences
only.
1.How does the cooling rate of magma influence
the formation of different types and textures of
igneous rocks?
2.What are the differences between intrusive and
extrusive igneous rocks, and how does their
formation environment affect their
characteristics?