Relative-Age Dating

1. Relative-Age Dating 8th Grade Earth and Space Science Class Notes

2. Door Projector Screen Oscar Rzadkiewicz Ethan Hilston Allison Radocaj Joshua Duch Madelynn Tomera Olivia Kim Brittney Reder Joshua Thomas David Davis Caitlin McDonough Ryan Marczak Brooke Anderson Sierra Strickland Samuel Meinert Mrs. Metcalfe Michael Kochmar Madison Pavlick Back of Room Teacher Desk Nicholas Fleisner Christopher Lofink Mrs. O’Lare Christian Parreaguirre Yasmine White Jonathan DeChicchis Lindsay Marczak Mrs. Picard Steven Dietz Christy McDermott Kaitlyn Daly Logan Glace Room 129 Seating Chart Period 1

3. Door Projector Screen Craig Semego Madison Bittner Tina Li Kenny Luong Christos Pappas Michael Fulcher Christina Del Nano Lavaughan Hawkins Savannah Clem Julianna Mitchell Alec Whipkey Anthony McGaw Stephana Lim Caleb Yip Back of Room Teacher Desk Lucas Lloyd Marlee Krakosky Jenna Izydore Brian Ammon Ashani Shah Kennedy Urban Jillian Sabatos Grace Brennan Amina Malik Timothy Harper Ryan Podlogar Rachel Shaheen Room 129 Seating Chart Period 2

4. Door Projector Screen Stephen Macioce Gabriela Hundley Charlene Acham John Martin Lindsay Boyle Hannah Dobies Cody Woods Jared Buckholt Back of Room Teacher Desk Trey Norman Alaina Strickler Jacob Pritchard Caitie Conway Natalie Disante Lisa MacCaglia Caitlin Brannon Derek Parker Room 129 Seating Chart Period 3

5. Door Projector Screen Cassandra Lewis Scott Nettrour Joseph Ohler Michael Kutzmas Seth Russell Eben Krigger Raphael Dymek Gretchen Schurman Tyler Baran Thomas Kim Noah Ingram Dustin Grossman Back of Room Teacher Desk Joshua Lugg Dillan Nudi David Barancyk Charles Groom Kyrsten Carr Caroline Bondi Sana Chaudhri Brian Kress Theodore Caye Caroline Huang Sawyer Smith Joshua Morgan Lucas Sterling Room 129 Seating Chart Period 6/7

6. Door Projector Screen Peyton Ferraro Krista Scibetta Benjamin Bernarding Sean Braithwaite Lauren Rogus Nathan Ziegler KC Anton Chase Fetsko Carly Martin Eric Staab Aaryan Jain Back of Room Teacher Desk Karli Strutz Mikayla Hensel Gina Foreman Blake Pillage Nicholas Carmassi Sonakski Sharma Anna Li Olivia Pagone Graham King Maxwell Gonzalez Room 129 Seating Chart Period 9

7. Tuesday, 1/22 Warm – Up • How can rocks be used to put events into chronological order? • Write down the HW. Learning Goal – Describe the Law of Superposition. Agenda • Find New Seats Using the Seating Chart • Warm-Up Question/Review HW • Update Table of Contents • Class Notes/Discussion of Relative-Age Dating • Work on Geologic Time Project/Section 21.2 Vocabulary Homework – Section 21.2 Vocabulary due on Wednesday, 1/23 Geologic Timelines due on Friday, 1/25

8. James Hutton • One of the 1st scientists to believe the Earth was very old • Attempted to explain that the earth changed over a very long period of time by the same processes

9. Uniformitarianism • States that geological processes occurring today have been occurring since the Earth first formed

10. Relative-Age Dating • Because of uniformitarianism, scientists can learn about the past by studying the present and the future • Relative-age dating does not allow scientists to determine exact age, but it gives a better understanding of the geologic events in the Earth’s history

11. An Example Use relative age dating to place the following events in U.S. History in the correct order: • Civil War • World War I • Revolutionary War • Vietnam War

12. Principles of Relative Dating • Used to determine relative ages • Original horizontality • Superposition • Cross-cutting relationships • Inclusions • Let’s look at each separately!

13. Original Horizontality • Principle that sedimentary rocks are deposited in horizontal (or nearly horizontal) layers

14. Superposition • States that in an undisturbed rock sequence, the oldest rocks are at the bottom and each consecutive layer is younger than the layer beneath it

15. Cross-cutting Relationships • States that intrusions are younger than the rock it cuts across • This also applies to faults

16. Inclusions • States that fragments (inclusions) in a rock layer must be older than the rock layer that contains them

17. Exceptions - Unconformities • Buried surfaces of erosion • Leaves a “gap” in the rock record • Three main types: • Disconformity • Nonconformity • Angular unconformity • Let’s examine these!

18. Disconformity • When a horizontal layer of sedimentary rock overlies another horizontal layer of sedimentary rock after a period of erosion

19. Nonconformity • When a layer of sedimentary rock overlies a layer of igneous or metamorphic rock

20. Angular Unconformity • When a horizontal layer of sedimentary rock is later laid down on top of the tilted, eroded layers • Usually occurs during mountain building • 21.10%20Angular%20Unconformity.swf

21. Correlation • Matching of unique rock outcrops or fossils exposed in one geographic region to similar outcrops exposed in other geographic regions • Example – The Grand Staircase

22. The Grand Staircase

23. Key Beds • A rock or sediment layer that serves as a time marker in the rock record and results from volcanic ash or meteorite-impact debris that spread out and covered large areas of Earth

24. Fossil Correlation • Correlating fossils from rock layers in one location to rock layers in another location shows that the layers were deposited during roughly the same time period, even though the layers are of different material

25. Example of Fossil Correlation