absolute and relative dating.pptx

Describe how layers of rocks (stratified rocks) are formed,
Describe the different methods (relative and absolute dating) to determine the age of stratified rocks, and
Explain how relative and absolute dating were used to determine the subdivisions of geologic time.
The relative age of a rock is its age when compared with the ages of other rocks�The absolute age of a rock is a calculation of the number of years that have passed since the rock formed.

1. Rock Formation II: Relative and Absolute Dating mirjam nilsson

2. A) Describe how layers of rocks (stratified rocks) are formed, B) Describe the different methods (relative and absolute dating) to determine the age of stratified rocks, and C) Explain how relative and absolute dating were used to determine the subdivisions of geologic time. Objectives

3. 20XX presentation title 3 The relative age of a rock is its age when compared with the ages of other rocks The absolute age of a rock is a calculation of the number of years that have passed since the rock formed.

4. How Layers of Rocks Are Formed

5. 20XX presentation title 5

6. . 20XX presentation title 6 How Sediments are formed and sediments are turned into layers of new rocks. Existing rocks can be broken down into small pieces called ________. 3 Main types of Weathering: 1.___________ - caused by temperature changing. __________ - when acid rain reacts with substances in rocks. __________ - plants or animals can break up rocks.

7. Sediments can be move away by: _______, ______, ______, ______. The combined process of weathering and transport is called ________. When sediments settle in warm place and some may sink at the bottom of the sea and this called _______. _______ when these layers the weight of the layers above compressed the ones below and are formed into sedimentary rocks. _________when substance sips between the sediments and hardened and glued together. 20XX presentation title 7

8. Methods to Determine the Age of Stratified Rocks Relative dating is a method of arranging geological events based on the rock sequence. Determining which fossils or events came first, second, third… etc … 20XX presentation title 8

9. Absolute Dating – determining the actual age of rock using radioactive decay 20XX presentation title 12

10. ABSOLUTE DATING the process of determining an age on a specified chronology in archaeology and geology (RADIOACTIVE DECAY) RELATIVE DATING the process of determining if one rock or geologic event is older or younger than another, without knowing their specific ages (GEOLOGIC SEQUENCING) 20XX presentation title 13

11. PRINCIPLES OF RELATIVE DATING Law of Superposition States that each layer of sediment is piled on top of another layer making the one on top of the strata the youngest one, while the layer at the bottom of the strata is the oldest.

12. The Law of Cross-Cutting Relationship States that igneous intrusion is always younger than the rock it cuts across Extrusion – a lava that is cooled and hardened in a surface. Intrusion – a magma that is cooled and hardened beneath the surface (hardened magma)

13. 20XX presentation title 17

14. 20XX presentation title 18

15. The Law of Inclusion The rocks that are mixed up in the formation of sediments are called INCLUSION These rocks are always older than the layer of sediments it is embedded. 20XX presentation title 19

16. Law of Horizontality Layers of sediments are originally deposited horizontally under the influence of gravity. Those strata's that are not found not in horizontal order may have been deformed by the movement of the earth’s crust. 20XX presentation title 20

17. Absolute Age of Rocks RADIOMETRIC DATING – radioactive isotopes found in fossils or rocks are used. 20XX presentation title 21

18. 20XX presentation title 22

19. Radioactive decay – the process by which an atomic nucleus of an unstable atom loses energy. Alpha, Beta and Gamma The original unstable isotope is called the parent isotope, and the more stable form is called the daughter isotope. Isotopes decay at an exponential rate that that can be described in terms of half-life. Half – life - it takes time for substance undergoing decay to decrease by half. 20XX presentation title 23

20. 20XX presentation title 25

21. 20XX presentation title 26