Foundations of Modern Geology

Two schools of thought: Neptunists

Abraham Gottlob Werner Universal ocean

Plutonists James Hutton Endless cycle of formation

Foundations of Modern Geology Principle of Uniformitarianism

Charles Lyle

Actualism1. Geologic processes observed today

occurred in the past2. Some past geologic processes no longer

occur3. The rate and intensity of geologic

processes may vary through geologic time

Geologic Time

Birth of a Solar System

Solar nebula model

Birth of a Solar System

Planetesimal hypothesis

Birth of a Solar System

Condensation Sequence

Rocky Planets & Gas Planets Rocky

Mercury Venus Earth Mars

Gas Jupiter Saturn Neptune Uranus

Rocky & Gas Planets

Figure 2-8

Other Celestial Bodies

Dating the Solar System

Dating the Solar System

Chapter 3

14

Interior of the Earth – Seismology Meteorites

Composition & age Density

Seismic Waves

Chapter 3

15

Seismic Waves

Surface waves Travel slowly along Earth’s surface

Body waves Travel at higher speeds through Earth’s

interior

Body waves

Chapter 3

16

Seismic Waves

Body Waves P-waves (primary)

All three states: solid, liquid, & gas

S-waves (secondary) Only solids

Chapter 317

Chapter 318

Models of Earth’s Formation

Sources of Earth’s Water

Cosmic gases Comets Meteorites

Wet Magma Ocean Hypothesis