section_path: Definition/Time periods
section_name: Time periods
paragraph_text: Time periods
  
  In dividing up human prehistory in Eurasia, historians typically use the three-age system, whereas scholars of pre-human time periods typically use the well-defined geologic record and its internationally defined stratum base within the geologic time scale. The three-age system is the periodization of human prehistory into three consecutive time periods, named for their predominant tool-making technologies: Stone Age, Bronze Age and Iron Age. In some areas, there is also a transition period between Stone Age and Bronze Age, the Chalcolithic or Copper Age.
  
  For the prehistory of the Americas see Pre-Columbian era.