Overview - Timescale, Physical Landscapes

Assembly and breakup of super continents are major constitutes to this eon.

• 2.5 bn -541 ma
  
• Division of Precambrian Superon
  
• Significant evidence of major ores present
  

Proterozoic

• Paleo-proterozoic
  
  • Siderian - 2500 - 2300 Mya
    
  • Rhyacian - 2300 - 2050 Mya
    
  • Orosirian - 2050 - 1800 Mya
    
  • Statherian - 1800 - 1600 Mya
    
  
  
  

• Meso-proterozoic
  
  • Calymmian - 1600 - 1400 Mya
    
  • Ectasian - 1400 - 1200 Mya
    
  • Stenian - 1200 - 1000 Mya
    
  
  
  

• Neo-proterozoic
  
  • Tonian - 1000 - 720 Mya
    
  • Cryogenian - 720 – 635 Mya
    
  • Ediacaran - 635 - 539 Mya
    
  
  
  

Landscape Development
2.5 billion years ago, island arcs and small cratons merged into a supercontinent.

• Between 2.4 and 2.2 billion years ago, this landmass was ripped apart by the penetration of numerous dolerite dikes across the continent.
  
• These dykes were formed when mantle plumes struck the base of the continental crust. This was the underlying cause of the first supercontinent breakup.
  
• Between 2.1 billion and 1.8 billion years ago, these fragments were rejoined by collision tectonics into a new supercontinent, Columbia. Modern plate tectonic processes were functioning at least 2.1 billion to 2 billion years ago, as indicated by two of the world's oldest well-preserved ophiolites.
  
•  The breakup of Colombia gave rise to many smaller continents and eventually, by about a billion years ago, to another supercontinent, a collection of several larger continents in close proximity to each other. This aggregation is called Rodinia.
  

During the Proterozoic, especially 2.1-1.8 billion years ago, 1.3-1.0 billion years ago, and 0.8-500 million years ago, many mountain belts were formed following the breakup of supercontinents and the collision of their debris.

New ocean basins were created by continental breakup and then destroyed by subduction zones

• The closure of these oceans caused continental blocks to collide, creating major mountain belts such as the Grenville Belt in eastern North America.