Bell Work 10-19-15
If you were to put the following events in to a
time sequence of first to last, how would you do
it? What else would you add?
Go to school
Wake up
Eat lunch
Put clothes on
WHAT’S IN THE ROCKS!
State Performance Indicators
 SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their
relative age
 Essential Learning: How do I compare fossils found in rock to determine their relative
age?
Objectives
Describe the process of relative dating to determine the age of
rocks
Compare and Contrast different types of fossils in sedimentary
rock to determine their relative age
TOC: Geologic History Notes
Sedimentary Rock
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
Sedimentary rocks cover 75% of the
Earth’s land area.
Layer after layer of eroded earth is
deposited on top of each. These layers
are pressed down more and more
through time, until the bottom layers
slowly turn into rock.
Relative Dating
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
Scientists use different methods to
determine the age of objects in
sedimentary rocks.
One method, Relative dating, examines
a fossil’s position within rock layers to
estimate its age.
 The bottom layers of rock are usually the
oldest, and the top layers are usually the
youngest.
 Scientists can use the order of rock layers to
determine the relative age of objects within the
layers.
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
Discuss with elbow partner
which layer is the oldest in
this rock column and which is
the youngest.
Identify the type of rock in the
oldest and youngest layers.
Which is the biggest fossil in the
rock column? Is the fossil
young or old relative to the
other fossils in the rock
column?
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
The Geologic Column
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
To make relative dating easier, geologists combine data from all
of the known rock sequences around the world.
From this information, geologists created the geologic column
— an ideal sequence of rock layers that contains all of the
known fossils and rock formations on Earth, arranging layers
from oldest to youngest.
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
Palaeontology
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
Palaeontology is the science involved with the study of
past life.
Scientists who study past life are called palaeontologists.
Palaeontologists collect data by studying fossils.
The remains or
physical evidence
of an organism
preserved by
geologic processes
is called a Fossil.
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
SPI 0807.5.5 Compare fossils found
sedimentary rock to determine their
relative age
 Fossils in rocks happen when organisms
die, the fleshy parts decompose and are
buried quickly in sedimentary rocks.
 The hard parts are left to become fossils.
Fossils in
Amber occurs
when insects
get stuck in
tree sap that
hardens
quickly.
SPI 0807.5.5 Compare fossils
found in sedimentary rock to
determine their relative age
 Petrification is the process in
which minerals replace an
organisms tissues.
 One form of petrification is
called permineralization,
which is the process in which
minerals fill in pore spaces of
an organism’s tissues.
SPI 0807.5.5 Compare fossils found in sedimentary ro
to determine their relative age
SPI 0807.5.5 Compare fossils found
sedimentary rock to determine their
relative age
 Frozen fossils occur
when animals are
frozen in ice and die.
We find them 1000s of
years later when it
thaws.
 Fossils in Asphalt
occurs when animals
are preserved in
thick, sticky pools of
asphalt.
Trace fossils are any naturally preserved evidence
of an animal’s activity.
Three types:
1.Track- footprint
2.Burrows- shelters made by animals
3.Coprolites- preserved animal dung
 elbow partner
Burrow
discuss and analyze
why tracks and
coprolites are
considered trace
fossils?
Coprolite
 Some fossils do not contain any
original material of the original
organism. Molds form when sediments
cover the organism, such as shell, and
the hard part is alter removed by
weathering or erosion.
A cast is an object that is created when
sediment fills a mold and becomes rock.
History of Changing Organisms
Scientists study the relationships between fossils to
interpret how life has changed over time.
Since the fossil record is incomplete, palaeontologists look
for similarities between fossils over time to try to track
change.
Using Fossils to Date Rocks
Scientists have found that particular
types of fossils appear only in
certain layers of rock.
By dating rock layers above and below these fossils,
scientists can determine the time span in which the
organism lived.
If the organism lived for a relatively short period of
time, its fossils would show up in limited layers.
Index fossils are
fossils of organisms
that lived for a
relatively short, well
defined geologic
timespan.
Trilobites
SPI 0807.5.5 Compare fossils found in
sedimentary rock to determine their
relative age
SPI 0807.5.5 (Fossils)
The diagram below shows three substrate layers with fossils.
1. Which statement is best supported by the diagram?
a
.A. The fossils in Layers 1 and 3 are from closely related organisms.
b
.B. The fossils in Layers 2 and 3 are from closely related organisms.
c
.C. The fossil in Layer 3 is older than the fossil in Layer 2.
d
.D. The fossil in Layer 1 is older than the fossil in Layer 2.
SPI 0807.5.5 (Fossils)
Two geologic columns are shown below. The columns are from areas about 1 kilometer
apart
2. Which layers were most likely deposited at the same time?
a. Layers 3 and 4
b.Layers 2 and 6
c. Layers 2 and 3
d.Layers 1 and 4
SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative age
SPI 0807.5.5 Compare fossils found in sedimentary rock to determine their relative
SPI 0807.5.5 (Fossils)
3. Scientists use a fossil’s position within rock layers to determine whether
the fossil is older or younger than other fossils in a process called
a. the geologic column. c. half-life.
b. relative dating.
d. absolute dating.
SPI 0807.5.5 (Fossils)
4. A scientist was digging for fossils along a rocky cliff. The scientist
discovered trilobite fossils in rocks at two different depths in the cliff.
What can be determined about the fossils based on their locations?
a. the diet of the trilobites
c. the relative age of the trilobite fossils
b. the size of trilobite population d. the number of trilobite predators
5. A cross section of rock layers is shown below.
Which fossil is found in the oldest layer?
a.dinosaur
b.shell
c.leaf
d.fish
Bell Work 10-20-15
 Compare the fossil layers shown below.
 Which organisms are most likely to be the same approximate age?
 a. 2 and 4
 b. 5 and 6
 c. 1 and 3
 d. 3 and 5
Using Fossils to Interpret the Past
Fossils can reveal changes in the environment.
Scientists have found marine fossils on mountaintops
(e.g. Yoho National Park)
The presence of these fossils means that rocks were
once below the surface of an ocean.
Middle TN, specifically Murfreesboro, was once covered
by a shallow sea.
Marine fossils found in the limestone tell scientists that.

FINDASAURUS
ACTIVITY
Scenario: A paleontologist from Tennessee went on vacation to Montana where he
discovered dinosaur bones in a particular layer of rock. He wondered if the same layer
existed in Tennessee so he could find bones closer to home. If that particular rock appears
on Earth’s surface, continuously, all the way from Montana to Tennessee he would be able
to walk along the layer to follow it. That would be easy, but unfortunately, the easy way
never seems to work. Erosion would make it impossible to follow the layer all the way
from Montana to Tennessee. One of the most reliable ways to locate fossils is with other
fossils. Index fossils can be used to track a layer from Montana to Tennessee, or from
Montana to France. Relative dating places events in sequence within the rock layers while
the process of determining if layers in different places are the same is called correlation.
 1.There are two stacks of rock layers, one in Montana and one in France. Your job is to
determine: Which layers in Montana correlate with layers in France by matching the
letters. Which layer in France contains the same dinosaur fossil as layer “d” in Montana.
 2.Draw the fossils in the layers shown on the chart. For example, index fossil #2 should be
drawn only in layers c and i. Make your best effort at reproducing the drawing.
 3.Using colored pencils connect the borders of the rock layers in Montana with those in
France.
 2-minute journal reflection using accountable talk ( I hypothesize that ...) on which layer is
correct and what you learned today.
Exit Ticket