UNIVERSITY OF SOUTH ALABAMA
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GY 112: Earth History
Lecture 13: Fossil
Preservation
Average: 82.1%
Highest grade: 99%
UNIVERSITY OF SOUTH ALABAMA
Last Time (before the exam)
1) Linne (the Linnaean System)
2) Taxonomy ordering
3) Some examples (important beasties you will see in
GY 112: Earth History
GY 112L)
Lecture 13: Fossil
Preservation
(Web Lecture 12)
Taxonomy
Taxonomy
Linne realized that there had to be some
structure in naming beasties. He proposed one.
The Linnaean System: a binomial classification
scheme based on Latin names.
Kingdom
Phylum
Largest Grouping
Class
Order
Family
Genus
Species
Smallest Grouping
Linne proposed a 7-fold division.
PEI Green Mussels = Perna viridis
Genus
Species
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Taxonomy
Phylum
Class
Order
Family
Genus
Species
Chordata
Mammalia
Carnivora
Felidae
Felis
domesticus
Taxonomy
leo
onca
concolor
Panthera
Canidae
pardus
(leopard)
Acinonyx
jubatus
(cheetah)
Canis
familiaris
(dog)
Domain
Kingdom
Phylum
Class
Order
Family
Largest Grouping
Genus
Species
Smallest Grouping
lupis (wolf)
adjustus
(jackal)
latrans
(coyote)
Urocyon
Primates
Rodentia
Monkeys
Humans, etc
Squirrels
Mices
Rats etc.
Aves (birds)
All are members of the Phylum
Chordata
(Animals with back bones)
Reptilia
Taxonomy Responsibilities
Sub-Phylum
Class/subclass
But over the years,
we identified more
and more beasties
requiring constant
revisions, including
an even larger
division… the
Domain
Domain
Eukarya
Kingdom
Animalia (animals)
Plantae (plants)
Fungi
Protista (single-celled)
Bacteria
Protobacteria,
Cyanobacteria
Archaea
Euryarchaeota,
Crenarchaeota
Today’s Agenda
Order
1) The fossil record
2) Types of fossil preservation
3) Trace fossils
Phylum
Porifera
Cnidaria
cinereoargent
eus
(Grey Fox)
Class: Anthozoa
Subclass: Zoantharia
Subclass: Tabulata
Subclass: Rugosa
Bryozoa
Brachiopoda
Arthropoda
Subphylum: Trilobita
Mollusca
Class: Gastropoda
Class: Bivalvia
Class: Cephalopoda
Echinodermata
(Web Lecture 13)
Order: Nautiloidea
Order: Ammonoidea
Order: Belemnoidea
Class: Echinoidea
Class: Crinoidea
Hemichordata
Chordata
Subphylum: Vertebrata
Class: Reptilia
Class: Mammalia
The Fossil Record
The Fossil Record
Fact: Only a (small?)
proportion of all of the
beasties that ever lived
(or will live) on the
Earth will ever be
preserved in the rock
record.
What Proportion?
Source: Heck's Iconographic Encyclopedia (1851)
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The Fossil Record
Fact: Only a (small?)
proportion of all of the
beasties that ever lived
(or will live) on the
Earth will ever be
preserved in the rock
record.
Fossil Preservation
How does something
get fossilized?
What Proportion?
Probably less than 5%
Fossil Preservation
How does something
get fossilized?
•Possess hard body parts
Fossil Preservation
How does something
get fossilized?
•Possess hard body parts
•Die “peacefully”
•Get buried quickly
Fossil Preservation
How does something
get fossilized?
•Possess hard body parts
•Die “peacefully”
Fossil Preservation
How does something
get fossilized?
•Possess hard body parts
•Die “peacefully”
•Get buried quickly
•Stay buried
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Fossil Preservation
How does something
get fossilized?
Fossil Preservation
•Possess hard body parts
•Die “peacefully”
•Get buried quickly
•Stay buried
•Avoid oxygen
(anaerobic environment)
Modes of Fossil Preservation
How does something
get fossilized?
•Possess hard body parts
•Die “peacefully”
•Get buried quickly
•Stay buried
•Avoid oxygen
(anaerobic environment)
•Get “fossilized”
Modes of Fossil Preservation
Most fossils in the rock record
were deposited in marine
environments.
Most fossils in the rock record
were deposited in marine
environments.
Most are composed of CaCO3
Modes of Fossil Preservation
Modes of Fossil Preservation
Aragonite
Calcite
Most fossils in the rock record
were deposited in marine
environments.
Most are composed of CaCO3
Two major mineral forms:
Calcite
and
Aragonite
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Modes of Fossil Preservation
Aragonite
Calcite
More soluble
Less Soluble
Modes of Fossil Preservation
Unaltered (Pristine) Aragonite
Chalky Aragonite
Modes of Fossil Preservation
Unaltered (Pristine) Aragonite
Modes of Fossil Preservation
Unaltered (Pristine) Aragonite
Completely dissolved
Partially dissolved
Modes of Fossil Preservation
a “hole” or mold
Modes of Fossil Preservation
Molds and Casts
Molds and Casts
External Mold: Impression of
the outside of a shell.
External Mold: Impression of
the outside of a shell.
Internal Mold: Impression of
the inside of a shell.
Source: www.humboldt.edu/.../MakingFossils.html
Source: www.humboldt.edu/.../MakingFossils.html
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Modes of Fossil Preservation
Modes of Fossil Preservation
Molds and Casts
Molds and Casts
External and Internal Molds:
Impression of the inside and
outside of a shell.
Cast: an filled-in external mold
Modes of Fossil Preservation
Modes of Fossil Preservation
Mineral Replacement
Molds and Casts
Cast: a filled-in external mold
Original shell/skeleton material (calcite/aragonite) replaced by other minerals:
Dolomite, chert, pyrite, phosphate, hematite, calcite etc.
source: http://paleo.cc/casts/yuep3.jpg
Source: http://gpc.edu/~pgore/myphotos/fossils/cast&mold.jpg
Modes of Fossil Preservation
Mineral Replacement
Petrifaction
Original shell/skeleton material (calcite/aragonite) replaced by other minerals:
Dolomite, chert, pyrite, phosphate, hematite, calcite etc.
Originally porous materials (wood or bone) are replaced by silica, and
the original pore space is filled by silica (perimineralization)
Source: http://www.lapidaryjournal.com
http://www.panoramio.com/photo/13153670
Modes of Fossil Preservation
Source: http://gpc.edu/~pgore/myphotos/fossils/cast&mold.jpg
Petrified Bone
Petrified Wood
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Modes of Fossil Preservation
Concretions
Carbonization
Fossils are encased in nodules that protect them from compaction (leaves, shells).
When split open, you get an impression of both sides of the beastie
Soft organic materials (leaves, graptolites, worms) are preserved as a thin (black
to brown) carbon film in sedimentary rocks. Requires anaerobic conditions
Source: www.humboldt.edu/.../MakingFossils.html
Modes of Fossil Preservation
Source: www.humboldt.edu/.../MakingFossils.html
Modes of Fossil Preservation
Types of Fossils
Body Fossils: Actually physical remains of a
beastie (shell, skeleton, tests, bones, eggs,
feathers, scales, wood etc.)
“Entombment”
Soft organic remains (insects) are
preserved in amber (fossil tree sap)
175 million year old “bird”
Archiopteryx sp.
Types of Fossils
Trace Fossils (Ichnofossils)
Ichnology: The study of trace fossils
Body Fossils: Actually physical remains of a
beastie (shell, skeleton, tests, bones, eggs,
feathers, scales, wood etc.)
Trace Fossils: Evidence that a beasties once
lived in a particular environment.
50 million year old bird footprints
Source: www.humboldt.edu/.../MakingFossils.html
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Trace Fossils (Ichnofossils)
Trace Fossils (Ichnofossils)
Ichnology: The study of trace fossils
Ichnology: The study of trace fossils
• Burrows: mostly vertical passages
made in soft sediment.
• Feeding Traces: mostly horizontal
paths made on top of sediment
• Borings: mostly vertical passages
made in solid material (wood, rock)
• Encrustation: attachment of fossils on
top of hard materials (e.g. worm tubes)
• Coprilite: fossil turds
• Burrows: mostly vertical passages
made in soft sediment.
• Feeding Traces: mostly horizontal
paths made on top of sediment
• Borings: mostly vertical passages
made in solid material (wood, rock)
• Encrustation: attachment of fossils on
top of hard materials (e.g. worm tubes)
• Coprilite: fossil turds
Trace Fossils (Ichnofossils)
Trace Fossils (Ichnofossils)
Ichnology: The study of trace fossils
Ichnology: The study of trace fossils
• Burrows: mostly vertical passages
made in soft sediment.
• Feeding Traces: mostly horizontal
paths made on top of sediment
• Borings: mostly vertical passages
made in solid material (wood, rock)
• Encrustation: attachment of fossils on
top of hard materials (e.g. worm tubes)
• Coprilite: fossil turds
• Burrows: mostly vertical passages
made in soft sediment.
• Feeding Traces: mostly horizontal
paths made on top of sediment
• Borings: mostly vertical passages
made in solid material (wood, rock)
• Encrustation: attachment of fossils on
top of hard materials (e.g. worm tubes)
• Coprilite: fossil turds
Trace Fossils (Ichnofossils)
Trace Fossils (Ichnofossils)
Ichnology: The study of trace fossils
• Burrows: mostly vertical passages
made in soft sediment.
• Feeding Traces: mostly horizontal
paths made on top of sediment
• Borings: mostly vertical passages
made in solid material (wood, rock)
• Encrustation: attachment of fossils on
top of hard materials (e.g. worm tubes)
• Coprilite: fossil turds
http://www.la
pidaryjournal
.com/feature/
apr05/rocks1.
jpg
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Today’s Homework
GY 112: Earth History
1) Sleep tonight (tomorrow is Mardi Gras)
2) Quiz Friday (multiple choice)
Lecture 13: Fossils Preservation
Instructor: Dr. Doug Haywick
dhaywick@jaguar1.usouthal.edu
Next Time
Lecture: Evolution Part 1
Lab 5: Fossil Preservation
This is a free open access lecture, but not for commercial purposed.
For personal use only.
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