If Rocks Could Only Talk, If Rocks Could Only Talk, What Would They Tell Us?What Would They Tell Us?
How Old is the Earth?How Old is the Earth?• 1 million years old?1 million years old?• 1 billion years old?1 billion years old?• No!No!• 4.6 billion years ago the earth had a 4.6 billion years ago the earth had a
violent beginningviolent beginning• Sit back as the story unfolds.Sit back as the story unfolds.
Once Upon a Once Upon a TimeTime……
PRECAMBRIAN ERAPRECAMBRIAN ERA
PALEOZOIC ERAPALEOZOIC ERA
MESOZOIC ERA ALSO KNOWN MESOZOIC ERA ALSO KNOWN AS “AGE OF THE REPTILES”AS “AGE OF THE REPTILES”
CENOZOIC ERA ALSO KNOWN CENOZOIC ERA ALSO KNOWN AS “AGE OF THE MAMMALS”AS “AGE OF THE MAMMALS”
How do we Know all This?How do we Know all This?
What is Igneous Rock?What is Igneous Rock?
• Formed from cooling Lava (outside Formed from cooling Lava (outside volcano) or Magma (inside volcano)volcano) or Magma (inside volcano)
• ExtrusiveExtrusive: cools outside the Earth’s Crust: cools outside the Earth’s Crust• IntrusiveIntrusive: Cools inside the Earth: Cools inside the Earth
Extrusive: Obsidian Intrusive: Granite
What is Sedimentary Rock?What is Sedimentary Rock?• Formed from Formed from
Weathering and Weathering and ErosionErosion
• TypesTypes::– Clastic: Clastic: pieces pieces
compacted and compacted and cemented togethercemented together
– Chemical: Chemical: formed by formed by evaporation and evaporation and precicpitationprecicpitation
– Organic:Organic: coming coming from living organismfrom living organism
What is Metamorphic Rock?What is Metamorphic Rock?• Formed by heat and pressureFormed by heat and pressure• FoliatedFoliated: Has bands: Has bands• NonfoliatedNonfoliated: Has no bands: Has no bands
How Can We Date Rocks?How Can We Date Rocks?
Half-life: The time it takes for half the element to decay
