Lecture 3

Geologic Time & Earth Systems  

Today's objectives -

• To understand the earth system and its five major reservoirs.
• To learn the time scales of earth-system processes.
• To learn how we use relative age dating to order rocks in chronologic sequence.
• To learn how we use radioactive decay to determine the absolute age of rocks.

 Vocabulary -

Rock cycle – 
Reservoir – 
Lithosphere – 
Hydrosphere –  
Atmosphere – 
Biosphere – 
Extraterrestrial –  
Relative time – 
Geologic Time Scale –  
Absolute dating – 
Radioactive decay –  
Half-life – 
Parent isotope –  
Daughter isotope –  
Effective dating range –  
Carbon-14 –  

Lecture Outline -

Rocks & the rock cycle
The Earth system and reservoirs: lithosphere, hydrosphere, atmosphere, biosphere, extraterrestrial
Geologic time
Relative age dating
Principles: horizontality & cross-cutting relationships
Absolute age dating & radioactive decay
Concept of half-lives
Isotopic systems
When can we use them
The age of the Earth