How much do you know about Paleontology? JOURNAL # 1 What is a fossil? (YOUR DEFINITION)

Geology: Paleontology & Geologic Time Created 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 #2 List 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 Sue Sue 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 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 Younger Layers of Rock Older Layers of Rock The Grand Canyon

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 #3 Draw 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

Draw the following geologic cross-section: 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

Draw a geologic cross-section with the following: 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-lives ISOTOPE HALF-LIFE PARENT DAUGHTER URANIUM 238 LEAD 206 4.5 BILLION YEARS POTASSIUM 40 ARGON 40 1.3 BILLION YEARS THORIUM 232 LEAD 208 14.0 BILLION YEARS CARBON 14 NITROGEN 14 5,730 YEARS

Sample Half-lives Iodine-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)

(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.