Today: 1) Quiz- Vocabulary Chapter 8 2) Lecture on Telling Time Geologically

Transcription

1 Today: 1) Quiz- Vocabulary Chapter 8 2) Lecture on Telling Time Geologically Next Class: 1) Go over Exam 2 2) Continue: Telling Time Geologically 3) In Class Exercise: Radiometric dating Introduction to the Grand Canyon 1

2 James Hutton ( ) Father of Geology James Hutton Charles Lyell 2

3 The Principle of Uniformitarianism 3

4 The Principle of Uniformitarianism 3

5 The Principle of Uniformitarianism Published in the Principles 3 of Geology, by Lyell

6 The Principle of Uniformitarianism Physical processes we observe today also operated in the past, at roughly comparable rates. Published in the Principles 3 of Geology, by Lyell

7 The Principle of Uniformitarianism Physical processes we observe today also operated in the past, at roughly comparable rates. The Present is the key to the past Published in the Principles 3 of Geology, by Lyell

8 The Principle of Uniformitarianism Physical processes we observe today also operated in the past, at roughly comparable rates. The Present is the key to the past Published in the Principles 4 of Geology, by Lyell

9 The Principle of Uniformitarianism Physical processes we observe today also operated in the past, at roughly comparable rates. The Present is the key to the past Published in the Principles 4 of Geology, by Lyell

10 The Principle of Uniformitarianism Physical processes we observe today also operated in the past, at roughly comparable rates. The Present is the key to the past Published in the Principles 4 of Geology, by Lyell

11 Relative Dating vs. Absolute Dating 5

12 Relative Dating vs. Absolute Dating 6

13 Phanerozoic - (Evident) Visible Life The Geologic Time Scale Hadean - Beneath the Earth (no Rocks) 7

14 Phanerozoic - (Evident) Visible Life The Geologic Time Scale Hadean - Beneath the Earth (no Rocks) 7 Archean- Ancient (Single-celled life)

15 Phanerozoic - (Evident) Visible Life The Geologic Time Scale Proterozoic-Early Life (multi-cellular life) Hadean - Beneath the Earth (no Rocks) 7 Archean- Ancient (Single-celled life)

16 Phanerozoic - (Evident) Visible Life The Geologic Time Scale Paleozoic- Old Life (complex life; coral fish, plants) Proterozoic-Early Life (multi-cellular life) Hadean - Beneath the Earth (no Rocks) 7 Archean- Ancient (Single-celled life)

17 Phanerozoic - (Evident) Visible Life The Geologic Time Scale Mesozoic - Middle Life (time of the Dinosaurs) Paleozoic- Old Life (complex life; coral fish, plants) Proterozoic-Early Life (multi-cellular life) Hadean - Beneath the Earth (no Rocks) 7 Archean- Ancient (Single-celled life)

18 Phanerozoic - (Evident) Visible Life The Geologic Time Scale Cenozoic - Recent Life (time of the mammals) Mesozoic - Middle Life (time of the Dinosaurs) Paleozoic- Old Life (complex life; coral fish, plants) Proterozoic-Early Life (multi-cellular life) Hadean - Beneath the Earth (no Rocks) 7 Archean- Ancient (Single-celled life)

19 The Scale of Geologic Time Hadean Archean Proterozoic Cenozoic Mesozoic Paleozoic 8

20 Geology: The science of the obvious (DeVecchio, 2012) 9

21 Principle of Original Horizontality River Beach Lake Sediment on Earth settles out of a fluid in a gravitational field, and accumulates on horizontal surfaces, therefore when originally deposited they are horizontal 10

22 Principle of Original Horizontality Cross-bedding Bedding 11

23 Principle of Original Horizontality 12

24 Principle of Superposition In a sequence of sedimentary rock layers (beds), each layer must be younger than the bed below. Principle applies to Sedimentary strata 13

25 Principle of Superposition 14

26 Principle of Lateral/Original Continuity Layers of sedimentary rocks can be continuous over broad areas when first deposited. Erosion may later remove part of a layer Principle applies to Sedimentary strata 15

27 Principle of Lateral/Original Continuity 16

28 The Vermillion Cliffs, Utah 17

29 Principle of Cross Cutting Relations If one geologic feature cuts across another, the feature that has been cut is older Principle applies to all rock types and Geologic structures 18

30 Principle of Inclusions The rock containing the inclusion must be younger than the rock that is included Principle applies to all rock types 19

31 Principle of Baked Contacts An igneous intrusion bakes (metamorphoses) sandstone surrounding rocks. The rock that is baked must be older than the limestone shale intrusion Principle applies to all rock types 20

32 Principle of Baked Contacts Tierra del Fuego, Chile Principle applies to all rock types 21

33 Principle of Baked Contacts Bingham Copper mine, Salt Lake City Principle applies to all rock types 22

34 Principle of Faunal Succession William Smith (ca. 1815) Book: The Map that Changed the World by Simon Winchester 23

35 Principle of Fossil Succession Principle applies to Sedimentary strata 24

36 Extinction Events and Geologic time 25

37 Distribution of sedimentary Rock Ages around the world: Correlation 26

38 Correlation 27

39 Correlation 28

40 29

41 Interpretation of Siccar Point Scotland, James Hutton (ca.1780) 30

42 Geologic Unconformity An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. A gap in the Geologic Time Record 31

43 Geologic Unconformity Angular unconformity Separates sedimentary that have different degrees of angular bedding dips 32

44 Geologic Unconformity Nonconformity Separates older non-layered igneous and metamorphic rocks from younger layered sedimentary rocks 33

45 Geologic Unconformity Disconformity Separates sedimentary strata that are parallel but have discontinuous ages Animation 34