EEPS (Planetary Formation and Earths History)

Unconformities

• Deposition

• Deformation

• Erosion

• Renewed deposition

Planetary Accretion

1. Giant spinning ball of gas and dust 

2. Flattens into a disk shape 

3. Material sticks together or collides to form clumps. 

4. Clumps become plants. 

Primitive atmosphere

The atmosphere began to form by degassing of the planet’s interior.

Primitive ocean

The atmosphere cooled.

• rain-filled basins forming primitive oceans—the “primordial soup”

Oldest rock

Jack Hills Zircons 4.4 Ga

Archean (4.0 - 2.5 Ga)

Life (Prokaryotes)

Very little oxygen in atmosphere

Proterozoic (2.5 - .5 Ga) 

First known “pollution crisis” 

• rise of atmospheric oxygen

Selective pressure drives the evolution of oxidative respiration. 

Snowball Earth (weathering of rocks)

Phanerozioc: Paleozoic

Rapid increase in biodiversity: Invertebrates like trilobites and cephalopods ruled the sea.

End Permian extinction

Sever extinction ever recorded

• Massive volcanism

• Rise in atmospheric CO₂

Mesozoic—Age of Dinosaurs

Pangea starts breaking up. Dinosaurs through the Triassic.

Cenozoic - Age of mammals 

Rise of grasslands - mammalian diversification 

Continents keep spreading apart. 

Paleocene-Eocene thermal maximum

Very rapid increase in temperature

Major increase in atmospheric CO₂.