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Unit 2 Lesson 2 Relative Dating Copyright © Houghton Mifflin Harcourt Publishing Company
Whos First? Copyright © Houghton Mifflin Harcourt Publishing Company What is relative dating? Scientists try to find out the order in which events happened during Earths history. They use rocks and fossils for relative dating, determining whether an object or event is older or younger than other objects or events. Scientists use different pieces of information about rocks to determine the relative age of each rock layer. Unit 2 Lesson 2 Relative Dating
How are undisturbed rock layers dated? Sedimentary rocks form when new sediments are deposited in horizontal layers on top of older rock. Over time, the layers pile up, with younger layers piling on top of older ones. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
How are undisturbed rock layers dated? Scientists use the order of rock layers to date the rock in each layer. The law of superposition is the principle that states that younger rocks lie above older rocks if the layers have not been disturbed. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
How Disturbing! Copyright © Houghton Mifflin Harcourt Publishing Company How are sedimentary rock layers disturbed? Forces in Earth can disturb rock layers in various ways. Tilting happens when Earths forces move rock layers up or down unevenly. The layers become slanted. Folding is the bending of rocks that can happen when rock layers are squeezed together. Older layers may end up on top of younger layers. Unit 2 Lesson 2 Relative Dating
How are sedimentary rock layers disturbed? Features such as faults and intrusions can cut across existing layers of rock. A fault is a break or crack in Earths crust where rocks can move. An intrusion is igneous rock that forms when magma is injected into rock and then cools and becomes hard. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
How are sedimentary rock layers disturbed? Finding the relative ages of rock layers can be even more complicated when an entire layer of rock is missing. A missing layer of rock is called an unconformity. It forms a gap in the geologic record. An unconformity is formed when rock layers are eroded or when sediment is not deposited for a long time. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
Im Cutting In! Copyright © Houghton Mifflin Harcourt Publishing Company How are rock layers ordered? The law of crosscutting relationships states that a fault or a body of rock, such as an intrusion, must be younger than any feature or layer of rock that the fault or rock body cuts through. The law of superposition and the law of crosscutting relationships help scientists figure out how rock layers formed. Unit 2 Lesson 2 Relative Dating
How are rock layers ordered? Using the laws of superposition and crosscutting relationships, determine the relative ages of rock layers and features in the image below. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
Dating Mars Copyright © Houghton Mifflin Harcourt Publishing Company The laws of superposition and crosscutting relationships are used to find the relative ages of features on Mars. A crater that cuts into another crater is the newer crater. A crater that is cut by another feature, such as a fracture, is older than the other feature.
So Far Away Copyright © Houghton Mifflin Harcourt Publishing Company How are fossils used to determine relative ages of rocks? Fossils are the traces or remains of an organism that lived long ago. Scientists can classify fossils based on changes over time, and they can use that classification to find the relative ages of rocks. Rocks containing fossils of organisms similar to those alive today are most likely younger than rocks containing fossils of more primitive organisms. Unit 2 Lesson 2 Relative Dating
How are geologic columns used to compare relative ages of rocks? Relative dating can also be done by comparing the relative ages of rock layers in different areas. A geologic column is an ordered arrangement of rock layers based on the relative ages of the rocks, with the oldest rocks at the bottom. Scientists develop geologic columns to piece together the geologic record of a large area. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
How are geologic columns used to compare relative ages of rocks? Scientists can compare the rock layers of different places with similar layers in the geologic column. Two layers that match probably formed around the same time. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 2 Relative Dating
Unit 2 Lesson 2 Relative Dating Copyright © Houghton Mifflin Harcourt Publishing Company.
Unit 7 Lesson 2 Relative Dating Copyright © Houghton Mifflin Harcourt Publishing Company.
Whos First? Copyright © Houghton Mifflin Harcourt Publishing Company What is relative dating? Scientists try to find out the order in which events happened.
Relative and Absolute Dating By: Mr. Meringolo. Before We Begin… Write down the following questions, answer them throughout the powerpoint What is relative.
Earth Systems Chapter Explain how relative dating is used in geology. 2. Explain the principle of superposition. 3. Describe how the geologic column.
RELATIVE DATING: WHICH CAME FIRST? Brainstorm Questions 1.Why do think the Grand Canyon looks the way it does? 2. Which layers of rock are the oldest?
The Law of Superposition Any method of determining whether an event or object is older or younger than another event. Comparing rock layers or fossils.
2 Types. Relative Dating Absolute Dating 1. Law of superposition – youngest layer on top; oldest layer on bottom.
Sci. 3-2 Relative Dating: Which Came First? Pages
7.4.c Students know that the rock cycle includes the formation of new sediment and rocks and that rocks are often found in layers, with the oldest generally.
Age and Movement of Rocks. How old is old? Relative Dating a method of determining if an object is older or younger than another object.
Beginning with a History of Geology. 1. Catastrophism 1. Earth was shaped by dramatic events called catastrophes 2. Like MASSIVE earthquakes, floods,
Relative Dating: Which Came First? Chapter 3 Section 2 p Vocabulary: 1. relative dating 2. superposition 3. geologic column 4. unconformity Rank.
The Rock and Fossil Record II. Relative Dating: Which Came First?
Chapter 8 Section 1 Pages #’s 1-4 Determining Relative Age.
Unit 5: Age of the Earth Objective: E5.3D Describe how index fossils can be used to determine time sequence. E5.3g Identify a sequence of geologic events.
Unit 3 Review Please see pages in your book for more information *This study guide is just to get you started studying– please look at your notes.
R ELATIVE D ATING : W HICH C AME F IRST ? Chapter 6 Section 2.
The Relative Age of Rocks Place in order from youngest to oldest A B C D EF.
Finding the Relative age of Rocks Essential Questions: How do geologists determine the relative age of rocks? How are index fossils useful to geologists?
RELATIVE TIME: When the age of rock is compared to the ages of other rocks or events in geological time. Can determine which layers are older than others.
Ch. 13 Section 2 Relative Ages of Rocks. Principle of Superposition The principle of superposition states that in undisturbed layers of rock, the oldest.
Relative Dating Earth Science What is it? Relative dating is the process of identifying the relative ages of the layers of the Earth. The goal of.
Geologists have developed a set of principles to compare the age of rock layers.
6.2 Relative Dating: Which Came First? Pgs
Dating Rock Layers. Relative vs. Absolute Age Relative Age? What is Relative Age? – The age of an object or event in comparison to another object or event.
Interpreting Earth’s Rocks to Determine Its Past History.
Stratigraphy Stratigraphy is the branch of geology that deals with the arrangement of rocks in layers.
The Relative Age Of Rocks Chapter 8 Section 2. Absolute Age Absolute Age of a rock is the number of years since that rock formed, its EXACT age. Ex. The.
Relative Dating (No, not your cousin) Finding the Relative Age of Rocks.
Fossils and Dating 8-2 notes. What you will learn: The rock cycle includes the formation of new sediment and rocks and that rocks are often found in layers,
The Rock Record Section 1 Key Ideas State the principle of uniformitarianism. Explain how the law of superposition can be used to determine the relative.
WELCOME TO CLASS. Agenda TODAY Sequencing Time Rock Record Notes Relative Age activity Hand back tests NEXT TIME Absolute age lab Geologic Time QUIZ.
Relative Dating of Rocks. Relative Dating and the Law of Superposition Relative dating is determining the age of a rock or geologic event when comparing.
Earth’s History How do we know about it?. What is Uniformitarianism? Uniformitarianism: –Is a theory developed by the Scottish geologist, James Hutton,
Relative Dating Superposition Original Horizontality Faulting Tilting/Folding Intrusions Unconformities Geologic Columns Rock Puzzles.
Jump to first page Geologic Time Chapter 34. Jump to first page Dating rocks n Relative dating F Compare events and put them in order based on their sequence.
DO NOW (Period 2 & 7 only) Use answer key to make correction to p. 2 in binder DO NOW QUESTION What kind of unconformity is shown below? Explain. Choices:
Dating Rocks Ways to tell the age of a rock. What are relative and absolute Locations?
RELATIVE AGE OF ROCKS Lesson Absolute or Relative? Anthony is the youngest. Melony is 4 years old. Michael is older then Sasha. Sasha is 16 years.
Relative Age dating Basic Principles. Principle of superposition In a sequence of undeformed sedimentary rocks, the oldest beds are on the bottom and.
Bell Ringer How do fossils form? Where are they found and describe each?
Erosion, & Types of Weathering Chapter 10. Erosion A process where water, wind, or gravity transports soil (sediment) from its source A process where.
Geologist interpret Earth’s history by studying sedimentary rocks Relative Dating.
The Rock Record Section 1 Section 1: Determining Relative Age Preview Objectives Uniformitarianism Relative Age Law of Superposition Principle of Original.
A Little Bit of History … The history of geologic time begins with the human interest in mining. Interests in rock units began to flourish with commercial.
Chapter 8 Section 1 Page 190 #’s 1-6 Determining Relative Age.
Aim Aim: How do we know the age of the Earth? I. Earth’s History Uniformitarianism A. Uniformitarianism – the principle that most of the geologic events.
Rocks and the Fossil Record. In 1788 a man named James Hutton wrote Theory of the Earth. In it he hypothesized that all the processes that we observe.
The relative age of rocks How old is the stuff around us?
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