Unconformities, Geologic Time Scale, and Uniformitarianism. Ms. P Science 2016

Transcription

1 Unconformities, Geologic Time Scale, and Uniformitarianism Ms. P Science 2016

2 Do Now due tomorrow! 1. Compare and contrast relative dating to absolute dating. 2. The Law of Superposition states that younger rocks lie above older rocks in an undisturbed sequence. What does the word undisturbed mean? 3. How do you think rock layers become disturbed?

3 The Law of Superposition Oldest rocks are at the bottom, newest rocks are at the top! In horizontal layers (original horizontality) of sedimentary rock, each layer is older than the layer above it and younger than the layer below it.

4 Gaps in the record Sometimes rock layers are missing all together creating a gap in the geologic record.

5 Unconformities: the missing evidence Missing rock layers create breaks in the rock layer sequence called unconformities. Another way of thinking about an unconformity is that it is a surface that represents a missing part of the geologic column.

6

7 Causes of Unconformities Non-deposition- when there is NO sediment deposited because the supply of sediment has been cut off. Erosion movement of sediments from one place to another.

8 C.F.U. 1. What is superposition? 2. Explain what an unconformity is. 3. What causes unconformities? 4. How do unconformities affect superposition?

9 What is paleontology? Paleontology: The scientific study of earth s past, particularly fossils. Paleontologists are scientist who study the earth s fossils. What is it called when an animal species is wiped out from the earth s surface.

10 Geologic Column Not all rock sequences have been undisturbed. Some rock forces are disturbed (moved) by forces within the earth. This makes it hard for geologist to determine the relative age of a rock. To determine the relative age of a rock scientist use a geologic column A geologic column is an arrangement of all the different rock layers from around the world in which the oldest rocks are at the bottom.

11 How was the earth formed? Geologic Uniformitarianism History The same process that have changed the earth in the past continue to change the earth today over a long period of time. Basically, the things that changed the earth in the past are changing the earth today.

12 Evidence supporting uniformitarianism Uniformitarianism Weathering, erosion, and deposition have shaped the earth s surface in the past and are continually shaping the earth s surface today Rocks that were formed in the past look similar to rocks today

13 Geologic Time Scale The geologic column represents the thousands of years that have passed since the first rocks formed on Earth. Altogether, geologist study years, and years, and YEARS of Earth s history. To make things easier, scientists have developed the geologic time scale which is a scale that divides the earth s history into distinct time intervals.

14

15

16 CFU 1. What does Uniformitarianism mean? How would we apply this term to the earth today? 2. What is the geologic time scale? 3. According to the geologic time scale organisms started out and became more over time. 4. How did organisms really start out though?

17 Do Now- day 2 QUIZ tomorrow! 1. What is an unconformity? 2. What are the causes of unconformities? 3. What does Uniformitarianism mean? How would we apply this term to the earth today? 4. What is the geologic time scale? 5. According to the geologic time scale organisms started out Simple and became more Complex over time. 6. How did organisms really start out though???

18 Paleontology Quiz tomorrow! Packets you need to study Fossils Law of Superposition Unconformities, the Geologic time scale, and Uniformitarianism

19 Geologic Column Activity Read the directions on you lab sheet silently as I read them aloud. Do NOT write on your directions sheet. One you are finished coloring, please raise you hand to ask for scissors. Glue sticks are in your basket

20 Geologic Column Activity Shapes = fossils Background = sediment Wavy lines = deposition was not continuous (maybe an unconformity!) Straight lines = deposition was continuous Color each layer a different color. Layers that are the same should be the same color. Match up the different outcrops according to the fossils (shapes) and sediment (background)

21 Catalyst 1. According to the geologic time scale organisms started out and became more over time. 2. What is the law of Superposition? 3. What is the geologic scale? 4. What is an index fossil? 5. How can fossils tell us about Earth s past?