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Today:1) Quiz- Vocabulary Chapter 82) Lecture on Telling Time Geologically

Next Class:1) Go over Exam 2 2) Continue: Telling Time Geologically3) In Class Exercise: Radiometric dating

Introduction to the Grand Canyon

Monday, November 25, 13

James Hutton (1727-97)

“Father of Geology”

Charles Lyell

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James Hutton

Monday, November 25, 13

The Principle of Uniformitarianism

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Monday, November 25, 13

The Principle of Uniformitarianism

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Monday, November 25, 13

The Principle of Uniformitarianism

3Published in the Principles of Geology, by LyellMonday, November 25, 13

The Principle of Uniformitarianism

Physical processes we observe today also operated in the past, at roughly comparable rates.

3Published in the Principles of Geology, by LyellMonday, November 25, 13

The Principle of Uniformitarianism

Physical processes we observe today also operated in the past, at roughly comparable rates.

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“The Present is the key to the past”

Published in the Principles of Geology, by LyellMonday, November 25, 13

The Principle of Uniformitarianism

Physical processes we observe today also operated in the past, at roughly comparable rates.

4

“The Present is the key to the past”

Published in the Principles of Geology, by LyellMonday, November 25, 13

The Principle of Uniformitarianism

Physical processes we observe today also operated in the past, at roughly comparable rates.

4

“The Present is the key to the past”

Published in the Principles of Geology, by LyellMonday, November 25, 13

The Principle of Uniformitarianism

Physical processes we observe today also operated in the past, at roughly comparable rates.

4

“The Present is the key to the past”

Published in the Principles of Geology, by LyellMonday, November 25, 13

Relative Datingvs.

Absolute Dating

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Monday, November 25, 13

Relative Datingvs.

Absolute Dating

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Monday, November 25, 13

The Geologic Time Scale

7Hadean - Beneath the Earth (no Rocks)

Phanerozoic

- (E

vide

nt) V

isib

le L

ife

Monday, November 25, 13

The Geologic Time Scale

7Hadean - Beneath the Earth (no Rocks)

Archean-“Ancient” (Single-celled life)

Phanerozoic

- (E

vide

nt) V

isib

le L

ife

Monday, November 25, 13

The Geologic Time Scale

7Hadean - Beneath the Earth (no Rocks)

Archean-“Ancient” (Single-celled life)

Proterozoic-Early Life (multi-cellular life)

Phanerozoic

- (E

vide

nt) V

isib

le L

ife

Monday, November 25, 13

The Geologic Time Scale

7Hadean - Beneath the Earth (no Rocks)

Archean-“Ancient” (Single-celled life)

Proterozoic-Early Life (multi-cellular life)

Paleozoic- “Old Life” (complex life; coral fish, plants)

Phanerozoic

- (E

vide

nt) V

isib

le L

ife

Monday, November 25, 13

The Geologic Time Scale

7Hadean - Beneath the Earth (no Rocks)

Archean-“Ancient” (Single-celled life)

Proterozoic-Early Life (multi-cellular life)

Paleozoic- “Old Life” (complex life; coral fish, plants)

Mesozoic - “Middle Life” (time of the Dinosaurs)

Phanerozoic

- (E

vide

nt) V

isib

le L

ife

Monday, November 25, 13

The Geologic Time Scale

7Hadean - Beneath the Earth (no Rocks)

Archean-“Ancient” (Single-celled life)

Proterozoic-Early Life (multi-cellular life)

Paleozoic- “Old Life” (complex life; coral fish, plants)

Mesozoic - “Middle Life” (time of the Dinosaurs)

Cenozoic - “Recent Life”(time of the mammals)

Phanerozoic

- (E

vide

nt) V

isib

le L

ife

Monday, November 25, 13

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The Scale of Geologic Time

Archean PaleozoicHadean Proterozoic

CenozoicMesozoic

Monday, November 25, 13

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

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Monday, November 25, 13

Principle of Original Horizontality

Sediment on Earth settles out of a fluid in a gravitational field, and accumulates on horizontal surfaces, therefore when originally deposited they are horizontal

River

Lake

River

Beach

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Monday, November 25, 13

Principle of Original Horizontality

River

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BeddingCross-bedding

Monday, November 25, 13

Principle of Original Horizontality

River

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Monday, November 25, 13

In a sequence of sedimentary rock layers (beds), each layer must be younger than the bed below.

Principle applies to Sedimentary strata

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Principle of Superposition

Monday, November 25, 13

Principle of Superposition

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Monday, November 25, 13

Principle of Lateral/Original Continuity

Principle applies to Sedimentary strata

Layers of sedimentary rocks can be continuous over broad areas when first

deposited. Erosion may later remove part of a layer

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Monday, November 25, 13

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Principle of Lateral/Original Continuity

Monday, November 25, 13

The Vermillion Cliffs, Utah

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Monday, November 25, 13

Principle of Cross Cutting Relations

Principle applies to all rock types and Geologic structures

If one geologic feature cuts across another, the feature that has been

cut is older

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Monday, November 25, 13

Principle of Inclusions

Principle applies to all rock types

The rock containing the inclusion must be younger than the rock that is included

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Monday, November 25, 13

Principle of Baked Contacts

Principle applies to all rock types

shale

limestone

sandstone

An igneous intrusion “bakes” (metamorphoses) surrounding rocks. The rock that is baked must be older than the intrusion

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Monday, November 25, 13

Principle of Baked Contacts

Principle applies to all rock types

Tierra del Fuego, Chile

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Monday, November 25, 13

Principle of Baked Contacts

Principle applies to all rock typesBingham Copper mine, Salt Lake City

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Monday, November 25, 13

Principle of Faunal Succession

William Smith (ca. 1815)

Book: “The Map that Changed the World” by Simon Winchester

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Monday, November 25, 13

Principle applies to Sedimentary strata

Principle of Fossil Succession

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Monday, November 25, 13

Extinction Events and Geologic time

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Monday, November 25, 13

Distribution of sedimentary Rock Ages around the world: Correlation

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Monday, November 25, 13

Correlation

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Monday, November 25, 13

Correlation

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Monday, November 25, 13

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Monday, November 25, 13

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

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Monday, November 25, 13

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”

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Monday, November 25, 13

Geologic UnconformityAngular unconformity Separates sedimentary that have different degrees of angular bedding dips

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Monday, November 25, 13

Geologic UnconformityNonconformity Separates older non-layered igneous and metamorphic rocks from younger layered sedimentary rocks

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Monday, November 25, 13

Geologic Unconformity

Animation

DisconformitySeparates sedimentary strata that are parallel but have discontinuous ages

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Monday, November 25, 13