Trace Fossil Replication by Kathleen Clough (Cloughk@grps.k12.mi.us)
I.
Knowledge needed, useful web links
Trace fossils occur in sedimentary layers, and are more common in low level
environments of deposition. Trace fossils are geological records of biological activity.
Trace fossils may be impressions made on the substrate by an organism: for example,
burrows, borings (bioerosion), urolites (erosion caused by evacuation of liquid wastes),
footprints and feeding marks, and root cavities. The term in its broadest sense also
includes the remains of other organic material produced by an organism — for example
coprolites (fossilized droppings) or chemical markers — or sedimentological structures
produced by biological means - for example, stromatolites. Trace fossils contrast with
body fossils, which are the fossilized remains of parts of organisms' bodies, usually
altered by later chemical activity or mineralization.
paleo.cortland.edu/tutorial/Trace%20Fossils/tracefossils.htm
www.peripatus.gen.nz/paleontology/trafos.html
en.wikipedia.org/wiki/Trace_fossil
museum.gov.ns.ca/mnh/nature/tracefossils/.../whatare.html
II.
Vocabulary
Cast
A sedimentary structure representing the infilling of an original
mark or depression made on top of a soft bed and preserved as a solid form on the
underside of the overlying bed
Fossil/trace fossil
Any remains, trace, or imprint of a plant or animal that has been
preserved in the earth’s crust since some past geologic or prehistoric time; loosely any
evidence of past life
Grain size
A mineral or rock particle with a diameter of less than a few
millimeters, such as a sand grain; also, a general term for particles of all sizes, as in the
expressions “fine-grained” and “course-grained”
Hardness
The resistance of a mineral to scratching; it is a property by which
minerals may be described
Mold
An impression made in the surrounding earth or rock material by
the exterior or interior of a fossil shell or other organic structure
Regression
Retreat of the sea from land areas; also, any change that converts
offshore, deep-water conditions to nearshore, shallow-water conditions, or that moves the
boundary between marine and nonmarine deposition toward the center of a marine basin
Sediment
liquid
Solid material that has settled down from a state of suspension in a
Transgression
The spread of sea over land areas
Viscosity
internal friction
The property of a substance to offer internal resistance to flow; its
III.
Goal of Lesson
The goal of the lesson is for students to create trace fossils, infer the environment of
deposition, and to estimate energy level needed to preserve fossil records.
IV.
Curriculum Connections
E.SE.06.11 Explain how physical and chemical weathering lead to erosion and the
formation of soils and sediments. (Pictured Rocks dunes)
E.ST.06.31 Explain how rocks and fossils are used to understand the age and
geological history of the Earth (timelines and relative dating, rock layers). (Mosquito
River, Hurricane River, Chapel, Miners)
SRSM.1
Reflecting on knowledge is the application of scientific knowledge to new
and different situations. Reflecting on how knowledge requires careful analysis of
evidence that guides decision-making and the application of science throughout history
and within society. (Grand Sable Dunes, Hurricane River, Mosquito River)
SIPM.1
Inquiry involves generating questions, conducting investigations, and
developing solutions to problems through reasoning and observation. (Fossil replication,
soil profiles, conservation, particle movement or sieving)
E.ES.07.13 Describe how the warming of the Earth by the sun produces winds and
ocean currents. (Energy to move particles, wind and waves)
E.ES.07.41 Explain how human activities (surface mining, deforestation, over
population, construction and urban development, farming, dams, landfills, and restoring
natural area) change the surface of the Earth and affect the survival of organisms.
(Ghost forest, National Parks, soil profiles, erosion)
E1.1h
Design and conduct a systematic investigation that tests a hypothesis.
Draw conclusions from data presented in charts or tables. (Fossil replication, soil
profiles, particle movement)
E3.1A
Discriminate between igneous, metamorphic, and sedimentary rocks and
describe the process that change one kind of rock into another. (Soil profiles, rock
identification, erosion rates)
E3.3C
Describe the motion of geologic features using equations relating rate,
time, and distance. (Dune migration, water movement, particulate movement)
E2.1B
Analyze the interactions between the major systems (geosphere,
atmosphere, hydrosphere, biosphere) that make up the Earth. (Interaction with water,
wind, and soil and rock)
E2.4B
Explain how the impact of human activities on the environment (e.g.
deforestation, air pollution, coral reef destruction) can be understood through the analysis
of interaction between the four Earth systems. (Conservation, erosion, decay)
E5.4B
Explain natural mechanisms that could result in significant changes in
climate (e.g. major volcanic eruptions, changes in sunlight received by Earth, and
meteoric impacts). (Rock identification, energy)
E5.3D
Describe how index fossils can be used to determine time sequence.
(Mosquito River, Grand Sable Dunes, Hurricane River)
V.
Materials and Technologies
Tupperware containers or paper plates
Sand
Plaster of Paris powder
Fossil imprint (e.g. shell, ripple marks, leaf imprint, foot or hand print)
Shredded paper or leaf litter
Small paint brush
Mixing bowl and spoon
IV.
Procedures/ Instructions
Initial conversation about what a fossil is, using accountable talk. Possibly show a
variety of pictures and have the students categorize them, (foot prints, ripple marks, trees,
shells, fish, worms, dinosaur bones). Include time in the discussion, (e.g. how long does
it take to make a fossil? What type of environment might it happen in?)
Distribute materials separated into group tubs, one tub to about four students.
Have students create a data chart with space enough for sketches. Include drying time,
depth and width of impression, fill method, viscosity or amount of water.
Students should decide what type of imprint they will use, and sketch it into data chart.
Fill the basin with sand about an inch thick, and create the desired impression. Measure
the width, and depth of the impression and record.
Determine viscosity desired for two different samples, mix plaster of paris for first trial,
and record the amount of water used.
Determine method of fill for impression, pouring, dumping, or dry with water added
later.
Optional (cover impression with leaf litter or shredded paper).
Fill impression with plaster, allow plaster to dry, and harden.
While waiting for first sample to dry, prepare second tray with the same impression, and
prepare second plaster of paris mixture.
Using the same method of fill complete second impression sample, and allow sample to
dry.
While waiting for plaster to dry, discuss what possible differences that could be found in
the samples.
Once plaster is dry remove the sample from the basin. Using small paint brush students
should remove remaining sand or leaf litter from plaster cast.
Examine casts and note any differences. Examine one other group’s samples that used a
different fill method, and discuss methods used to create them. Compare plaster mixtures
and record findings.
If time and materials allow, students can try alternate fill methods and different
viscosities.
If time and materials allow, students can alter composition of fill material by adding
debris, (e.g. pebbles, leaves, rocks).
Answer questions and complete data chart.
VII.
Hands-on Connections
Sketch of
impression
Width of
impression
Depth of
impression
Viscosity of fill
Method of fill
Depth of
impression
Viscosity of fill
Method of fill
Second group’s findings
Sketch of
impression
Width of
impression
How did the viscosity of plaster influence quality of impression?
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How did the method of filling impression influence quality of impression?
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How did the type of impression influence preserved sample?
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Do different fill rates influence quality of impression preservation?
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What energy level of filling would produce the best trace fossils?
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What viscosity of fill material would produce the best casts of trace fossils?
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VIII.
Assessment Rubric
Data
Inferences
Implications
EX
Organized, clear
record of data in
table
Well thought
through and clearly
explained
Impact of fill on
trace fossil clearly
explained
Good
Poor
OK record of testing Minimal data, not
done in table
clear, scattered
Thought out, and
explained
Impact of fill on
trace fossils OK
explanation
Minimal
connections, little
thought
No explanation of
impact fill has on
trace fossil
production