Paleontology Notes

Relative Age is the “age” of a rock or strata compared to the ages of other rocks or strata.

Relative Age

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

The law states that layers of sediment were originally deposited horizontally under the action of gravity. Law of Horizontality

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.

Uniformitarianism claims the Earth is 4.6 billion years old.

Law of Fossil Succession Also known as the law of faunal succession, is based on the observation that sedimentary rock strata contain fossilized flora and fauna, and that these fossils succeed each other vertically in a specific, reliable order that can be identified over wide horizontal distances.

What does the Principle of Superposition say? 1.Sedimentary rocks form in rivers 2.Igneous rocks form faster than sedimentary 3.New rock layers form on top of older ones 4.There are billions of fossils on Earth

Which layer of rock is the oldest? They are all the same age

HOW OLD WOULD MOST GEOLOGISTS SAY THE EARTH IS? years 2.75,000 years 3.20 million years billion years

According to what theory, is the earth 4.6 billion years old? 1.Catastrophism 2.Uniformitarianism 3.Geologism 4.Agism

Flashback

Principles of Geology

Paleontology Notes

Crosscutting Relationships An igneous rock, fault, or other geologic feature must be younger than any rock across which it cuts..

Extrusions are igneous rocks layers that form on the surface when lava hardens.

Crosscutting Relationships Faults, Folds, Intrusions, Extrusions, Unconformities, Nonconformities, Disconformities

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

Intrusion Devil’s Tower, WY

In the image below identify as many intrusions and extrusions as you can!

Stop and Summarize

Journal #3 - 1 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 3 rd layer of sedimentary rock forms. 4.) An intrusion cuts through the all the rock layers, but not to the surface. 5.) A 4 th 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

Shoshone Fault, CA

Folds occur when rock layers are compressed together and bend or curve.

Folds Guadalajara, Spain

Folds Mojave Desert, CA

Stop and Summarize

Journal #3 - 2 Draw the following geologic cross-section: 1.) 2 layers of sedimentary rock form and a fold occurs causing the layers to bend and curve 3.) A 3 rd sedimentary layer forms. 4.) A fault cuts through all the layers 5.) A 4 th 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

Disconformities are gaps created when erosion occurs on an overlying rock layer.

Disconformity

Nonconformity are formed when sedimentary rock overlays igneous or metamorphic rocks.

Nonconformity

Egypt

Unconformities

Stop and Summarize

SOME Relative Dating Practice Write the correct order of events by numbering their occurrences. Include any and all cross-cut relationships.

Relative Dating Example

Relative Dating

Correlation is using rock and fossil evidence to match up dating at different locations.

Correlation

Index Fossils are used for dating the rock layers in which they are found.

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 Correlation using index fossils

Index Fossil Correlation using index fossils

What kind of cross- cut is shown to the right? 1.Intrusion 2.Extrusion 3.Folds 4.Unconformity

What kind of cross-cut is shown to the right? 1.Intrusion 2.Fault 3.Fold 4.Angular Unconformity

What kind of cross-cut is shown to the right? 1.Intrusion 2.Fault 3.Fold 4.Angular Unconformity

What is the name of the type of fossil is used to correlate rock layers at two or more different locations? 1.Mold 2.Petrified fossil 3.Index fossil 4.Trace fossil

Using correlation, Which two layers would you determine to be of the same age? 1.A & D 2.A & B 3.B & D 4.B & E

Paleontology Notes READY YOUR REMOTE FOR A QUICK REVIEW

What type of cross-cut appears at location e? 1.Fault 2.Fold 3.Nonconformity 4.Angular Unconformity

What type of cross- cut appears in the picture? 1.Fault 2.Disconformity 3.Nonconformity 4.Angular Unconformity

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.

Journal TURN TO YOUR JOURNAL PAGE

Journal #5 Draw a geologic cross-section with the following: 1.) At least 3 sedimentary rock layers 2.) At least 3 cross-cuts (faults, folds, intrusions, extrusions, or unconformities, angular unconformities, nonconformity, disconformity) Write a geologic history that explains the order of occurrence of each event.

Paleontology Notes READY YOUR REMOTE FOR A QUICK REVIEW

Which of the following is oldest? 1.Sandstone B 2.Sandstone A 3.Earthquake fault 4.Igneous Dike B

What type of cross-cut appears at location e? 1.Fault 2.Fold 3.Nonconformity 4.Angular Unconformity

What type of cross- cut appears in the picture? 1.Fault 2.Disconformity 3.Nonconformity 4.Angular Unconformity

- Albert Einstein “The important thing is to never stop questioning.”

How much do you know about Paleontology? Pre-Unit Questions (Post-Unit) Answer the following True/False Questions

How much do you know about Paleontology? Pre-Unit Questions (Post-Unit) Answer the following True/False Questions

Many scientists theorize that dinosaurs were wiped out many years ago by some great catastrophe. 1.True 2.False

How much do you know about Paleontology?  TRUE. Obviously dinosaurs don’t exist today and they seem to disappear suddenly from the fossil record.

Fossils take millions of years to form. 1.True 2.False

How much do you know about Paleontology? TRUE or FALSE?  FALSE. Fossils can form in less than a year depending on the conditions.

There are billions of fossils found all over the earth. 1.True 2.False

How much do you know about Paleontology?  TRUE. There are many fossils buried in the rock all over the planet. Over 99% of them are small marine plants and animals.

Dinosaurs are “giant lizards.” 1.True 2.False

How much do you know about Paleontology?  FALSE. Some were large, but many were not. The term dinosaur, coined in the 1800’s, does mean “terrible lizard,” but the average size of a dinosaur was that of a large dog.

JOURNAL # 6 Describe & discuss at least three new facts that you learned about paleontology while studying this unit.

RETURN YOUR REMOTE Classwork Assignments 1.) Journal # 6 2.) Relative Dating Geologic Cross- Sections WS 3.) Paleontology Test Review

Partner Assignment 1.) Draw a geologic Cross-Section on a blank piece of paper 2.) Include at least 5 sedimentary layers & 3 cross-cuts (intrusions, extrusions, faults, folds, or unconformities) 3.) Swap with a friend & have him/her number the events