GEY1112_L08_Fossilization_JElyWasinger
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School
Front Range Community College *
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Course
1112
Subject
Geology
Date
Dec 6, 2023
Type
docx
Pages
7
Uploaded by CountAlligator3653
GEY1112
Name: Jay Ely-Wasinger
Date: October 17, 2023
Class/section:
GEY1112-C11
Instructor: Kristin Quadracci
Lab Partner(s): Doggos
(Read, there totally is dog hair in my casts
and probably the molds too, it’s everywhere!)
Lab 8 - Fossilization
Original, completed Lab Notebook pages for the following are included in this
Lab submission:
I. Pre-lab questions
II. Experiment 1
Includes:
Legible photos or scans (with name card) of step 10 (one each pressing
shell
into sand and soil, for a total of two photos)
Legible photos or scans (with name card) per step 19
Fossilization
Please note: for any questions that require additional research, consider using Google
Scholar instead of Google. Also, any information taken/used from a source should be
properly cited.
PRE-LAB QUESTIONS
1.
Describe three methods of soft tissue preservation.
Soft tissues can be preserved by carbonization-- organisms are trapped in a sudden
event and fossilized, cryo-fossilization, where an organism is exposed to deep freezing
temperatures to preserve the soft tissues, or entrapment, where an organism becomes
fossilized in a substance like tree sap.
2.
What is the difference between a trace fossil and a mold?
Trace fossils are essentially evidence of organisms that are tapped in time, such as fossil
burrows, while a mold is a fossilized impression such as the footsteps buried in sediment at
Dinosaur Ridge.
3.
In what types of environments are body fossils most likely to occur? Why is this?
Body fossils are most likely to occur in places like river beds and marine environments
because these types of environments allow for rapid burial to preserve the fossil.
Fossilization
EXPERIMENT 1: METHODS AND ENVIRONMENTS OF
FOSSILIZATION
Data Sheet
Table 1. Shell Measurements
Measurement
Original Shell
(cm)
Plaster Shell in
Sand
(cm)
Plaster Shell in
Soil
(cm)
Plaster Shell in
Play-doh
®
(cm)
Length
3.6 cm
3.8 cm
3.9 cm
3.5 cm
Width
2.7 cm
3.5 cm
3.1 cm
2,7 cm
Depth
1.1 cm
1.5 cm
1.4 cm
1.0 cm
Table 2. Plaster Shell Observations
Sand
Potting soil
Play-doh
®
Observations
No real shape, kind of just
a lump where the shell
imprinted in the sand, but it
caved in on itself quickly
Better than the sand, but the
shape itself is very lumpy due
to the texture of the soil. Still
able to see some ridging from
the shell, but very muted.
Perfect little shell impression
just a tiny bit smaller than
the shell, 10/10 good job for
this guy.
Fossilization
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Pictures of shell molds:
Fossilization
Pictures of plaster shells:
Fossilization
Post-Lab Questions
1.
Identify which objects are the molds and which are the casts in your experiment.
In this experiment, the sand, soil, and Play-Doh were molds, and the plaster of Paris
acted as a cast.
4.
Compare and contrast the shell to the cast for each material.
Soil- The cast in the soil is very rigid from the pieces of wood and perlite pieces that are
present in the soil. Due to the excess material within the dirt, much of the detail was lost,
but the shape of the shell is much more prominent than the cast from the sand.
Sand-
Relatively like the caved shape of the shell, but there’s no definition of the shell
itself, the cast is just a cast of a hole.
Playdoh- The cast of the shell from the Play-Doh was a perfect replica of the shell itself.
All the details were preserved and it’s the exact size and shape of the shell itself.
5.
How was the formation of your mold and cast different from mold formation in nature?
In nature, the molds are sometimes weathered and altered before deposition has the
chance to preserve the mold. In this formation, however, it was an immediate cast after
the mold was formed, so there wasn’t a chance for it to be altered before being cast.
6.
Which cast provided more information about the once living object? Why?
The Play-Doh cast provided the most information about the object cast because it’s a
stable enough medium to allow the details of the object to remain set in place after it’s
removed.
Fossilization
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7.
Describe how each of the following factors influence the process of soft tissue
preservation.
a.
Rate of deposition- The higher the deposition rate, the better picture we get of
the organisms from the past. If the specimen is not quickly preserved, it will be
scavenged and quickly decay.
b.
The presence of water and oxygen- The more water and oxygen present, the
less likely it is to see good preservation of the soft tissue. Good areas that allow
for soft tissue preservation have little water and oxygen present.
8.
What type of environment would you expect to best preserve hard fossils? Use evidence
from this experiment to support your answer. Discuss the preservation of hard parts and
soft tissues.
Based on this experiment, clay-heavy environments would best preserve hard fossils,
due to their smooth texture allowing for full, clear impressions, and clays hold their
shape the best of the three mediums we used in this experiment.
Historical Geology. (2020, May 27). Wikibooks, The Free Textbook Project.
Retrieved
(12:47 PM, 10/19/2023)
from https://en.wikibooks.org/w/index.php?
title=Historical_Geology&oldid=3693288
Fossilization