how much do you know about paleontology? journal # 1 what is a fossil? (your definition)
TRANSCRIPT
How much do you know about Paleontology?
JOURNAL # 1
What is a fossil?
(YOUR DEFINITION)
Geology:Paleontolog
y & Geologic
TimeCreated in 2008 by Tim F. Rowbotham
Geology is the study of
the origin, history, and structure of the earth.
Paleontology
is the study of prehistoric life, particularly through fossil remains.
Fossils are the remains,
imprints, or traces of prehistoric organisms.
Fossil Formation Requires shelter
from scavengers, decay, and physical destruction.
Fossil Formation• Most commonly occurs
through quick burial by sediment.
• Is more likely to occur with hard parts such as bone, shells, and teeth.
Types of Fossils
Types of Fossils• Permineralized
remains• Carbon films• Molds & Casts• Original Remains• Trace Fossils
Permineralized Remains
occur when parts of the original remains are replaced by minerals flowing through ground water.
This process is called petrification.
Permineralized Remains
Fossil turtle shell
Permineralized Remains
Fossil dimetrodon
Permineralized Remains
Petrified wood
Permineralized Remains
Baby protoceratops
Permineralized Remains
Whale fossil
Permineralized Remains
Fossil tyrannosaurus
Carbon Films occur when
pressure from layers of sediment leaves only a thin carbon residue.
Carbon Films
Beech leaf
Carbon Films
Ancient salamander
Carbon Films
Fossil fish
Molds & Casts
Formation of fossil shell molds
Molds are hollow areas
left in sediment that show the shape of the original organism.
Molds & Casts
External mold of shell
Molds & Casts
Internal mold of shell
Casts are copies of the
shape of original organism that form from minerals deposited into the mold.
Molds & Casts
Cast of trilobite
Molds & Casts
Formation of fossil shell molds
Original Remains including the soft
parts of the organism are sometimes found in hardened tree resin, frozen ground, or tar pits.
Original Remains
Bee encased in amber
Original Remains
Scorpion in amber
Original Remains
Mammoth hair
Trace Fossils provide evidence
of an organism’s activity. They include footprints, trails, burrows, and excrement.
Trace Fossils
Dinosaur tracks
Trace Fossils
Fossil trails of climactichnites
Trace Fossils
Fossil burrows
Journal #2List 3 types of fossils and give a
brief description of each.
READY YOUR REMOTES
How fossils form VIDEOS
• How Fossils are Formed 2• How Fossils are Formed 1
Fun Facts about SueSue Wiki
Relative Age is the age of a
rock or fossil compared to the ages of other rocks or fossils.
Catastrophism is the belief that the
earth’s geological features were formed rapidly as a result of large catastrophes.
Catastrophes that could cause
rapid geologic change include landslides, volcanic eruptions, floods, and earthquakes.
Uniformitarianism is the idea that the
processes occurring on earth today are similar to those that occurred in the past.
Uniformitarianism basically says
“The present is the key to the past.”
Uniformitarianism is the idea that
geological features formed slowly over long periods of time.
Catastrophism vs. Uniformitarianism
Uniformitarianism
Catastrophism
Geologic Features
Form slowly over time
Form rapidly due to major
forces & events
Age of the earth Billions of years Thousands of
years
Catastrophism & a Young Earth
Where would dinosaurs fit in?
DRAGONS or DINOSAURS VIDEO
(FULL VIDEO 1:24)
3:09 – ?
Principle of Superposition
as sedimentary rocks form, they are deposited on older rock layers.
Principle of Superposition
in undisturbed layers, the oldest is on the bottom and higher layers are younger.
Principle of Superposition
Oldest layer is on bottom (1)
Principle of Superposition
The Grand Canyon
Principle of Superposition
The Grand Canyon
Principle of Superposition
The Grand Canyon
Younger Layers of Rock
Older Layers of Rock
Extrusions are igneous
rocks layers that form on the surface when lava hardens.
Extrusions
are always younger than the layers over which they form.
Extrusion
Kubu Rock – Botswana, Africa
Intrusions are igneous
rocks that form when magma pushes up into rock layers.
Intrusions are always
younger than the rock layers they invade.
Intrusion
Devil’s Tower, WY
Intrusions & Extrusions
Journal #3Draw the following geologic cross-section:
1.) 2 layers of sedimentary rock form.
2.) An extrusion forms on top of the two layers.
3.) A 3rd layer of sedimentary rock forms.
4.) An intrusion cuts through the all the rock layers, but not to the surface.
5.) A 4th layer of sedimentary rock forms.
Faults are breaks in the
earth’s crust. A fault is always younger than the rock it cuts through.
Faults
Faults
Shoshone Fault, CA
Folds occur when
rock layers are compressed together and bend or curve.
Folds
Guadalajara, Spain
Folds
Mojave Desert, CA
Folds
• South Wales, Australia
Journal #4
Draw the following geologic cross-section:
1.) 2 layers of sedimentary rock form.
2.) The 2 layers of rock are folded.
3.) A 3rd sedimentary layer forms.
4.) A fault cuts through all the layers, shifting some rock up.
5.) A 4th sedimentary layer forms.
6.) An intrusion cuts all the way to the surface forming an extrusion.
Unconformities are gaps in the
rock sequence (caused by the erosion of rock layers).
Angular Unconformity occur when rock
layers are tilted or uplifted, and then worn down by erosion and weathering.
Sediments are then deposited on top of these eroded layers.
Angular Unconformity
Angular Unconformity
Angular Unconformity
Angular Unconformity
Grand Canyon
Angular Unconformity
Siccar Point, Scotland
Angular Unconformity
Combs Quarry, Yorkshire, England
Disconformities are gaps created
when erosion occurs on an overlying rock layer.
Disconformity
Disconformity
Disconformity
Nonconformity are formed when
sedimentary rock overlays igneous or metamorphic rocks.
Nonconformity
Nonconformity
Nonconformity
Grand Canyon
Nonconformity
Egypt
Unconformities
SOME Relative Dating Practice
Write the correct order of events by numbering their occurances.
Include any and all cross-cut relationships.
Relative Dating Example
Relative Dating
Relative Dating
Relative Dating
Correlation is using rock and
fossil evidence to match up dating at different locations.
Correlation
Correlation
Correlation
Index Fossils are used for
dating the rock layers in which they are found.
(p. 4 Notes)
Index Fossils are species that
were abundant all over the earth, but existed for shorter periods of time.
Index Fossil
trilobite
Index Fossil
ammonite
Index Fossil
reptaculite
Index Fossil
Correlation using index fossils
Index Fossil
Correlation using index fossils
Index Fossil
Correlation
Journal #5
Draw a geologic cross-section with the following:
1.) At least 5 sedimentary rock layers
2.) At least 3 cross-cuts
Write a geologic history that explains the order of occurrence of each event.
Paleontology Notes
RETURN YOUR REMOTE
Finding Clues to Rock Layers
HW: (Pal Pack) p.18 “The Grandest
Canyon of All” p.19 “Relative Order of
Geologic Events” p. 20 “Geologic Puzzles”
Absolute Age is the age in years
of a rock or other object (as determined by radiometric dating.
Radiometric Dating
entails finding the amount of certain radioactive elements left in a rock or object.
Radioactive Decay is the release of
particles and energy from the nuclei of unstable atoms.
Radioactive Elements are elements
whose nuclei are unable to hold together, and eject particles and energy.
The Parent Element is the element
whose nucleus radioactively decays into another element.
The Daughter Element
is the new element that is produced after the decay of the parent element.
Half-Life is the time it
takes for half of the atoms in a sample to decay.
Half-Life is always the
same. It does not depend on the amount of atoms.
Half-Life is unaffected by
almost all other outside factors. Decay occurs at a steady rate.
Sample Half-livesISOTOPE
HALF-LIFEPARENT DAUGHTER
URANIUM 238
LEAD 2064.5 BILLION
YEARSPOTASSIUM
40ARGON 40
1.3 BILLION YEARS
THORIUM 232
LEAD 20814.0 BILLION
YEARS
CARBON 14NITROGEN
145,730 YEARS
Sample Half-livesIodine-129 16,000,000 years
Carbon-14 5730 years
Strontium-90 28 years
Sodium-24 15 hours
Technetium-99 6 hours
Fluorine-18 110 minutes
Oxygen-15 124 seconds
Radiometric Dating
As time passes, the amount of a parent isotope in a rock decreases as it decays.
It has decayed into the daughter element.
Radiometric Dating
basically involves measuring how much of the daughter element has formed.
Age Determination
can then be made by using the known half-life to determine how much time has passed.
Age Determination
typically, the dating can be estimated only up to a MAX of 10 half-lives.
Common Types of Radiometric Dating
Potassium-argon dating
Uranium-lead dating
Rubidium-strontium dating
Radiocarbon dating
Potassium- Argon Dating
Potassium-40 decays to Argon-40.
Potassium-40 has a half-life of 1,300,000,000 years.
(used on igneous & metamorphic rock)
Uranium-Lead Dating
Uranium-235 decays to Lead-207
Half-life: 700,000,000 years
Uranium-238 decays to Lead-204 Half-life: 4,500,000,000 years
(used on igneous & metamorphic rock)
Rubidium-Strontium Dating
Rubidium-87 decays to Strontium-87
Rubidium has a half-life of 50,000,000,000 years.
(used on igneous & metamorphic rock)
Radiocarbon Dating
Carbon-14 decays to Nitrogen-14.
Carbon dating is used to measure how long an organism has been dead.