Overview - Timescale, Physical Landscapes

• 2,588,000 - Present
  
• Division of Cenozoic era
  
  The Quaternary has been marked by several glacial periods during which vast expanses of the continents' temperate regions were covered by ice sheets that were many kilometers thick. Worldwide environments have been altered as a result of the rapid changes in climate and sea level that have occurred during and between these glacial periods. As a result, both flora and fauna as well as other life forms have undergone rapid changes. They were in charge of the emergence of modern humans starting around 200,000 years ago.
  
  Phanerozoic eon
  
  • Quaternary Period
    
    
    • Pleistocene
      
      • Gelasian
        
      • Calabrian
        
      • Chibanian
        
      • Stage 4
        
      
      
      
    
    
    • Holocene
      
      • Greenlandian
        
      • Northgrippian
        
      • Meghalayan
        
      
      
      
    
    
    
  
  
  
  

The ice's advances into temperate latitudes of the Northern Hemisphere were the most noticeable changes during the Quaternary. With the exception of the highest peaks in the interior, the glacial landscapes were dominated by several kilometers thick layers of ice. The Barents, Kara, and Laptev seas, much of the Canadian coast, and the Gulf of Maine all had grounded ice that extended onto the continental shelf. The Norwegian Sea and the Gulf of Maine are two locations where it is hypothesized that ice shelves similar to those seen today in the Ross and Weddell seas of Antarctica existed. They were also probably present in many other places. Polar jet streams were diverted southward to the glacial margins and beyond by high ice and domes of cold, high-pressure air. In addition, the ice sheets' sinking cold air generated powerful katabatic winds that dried the land nearby. Permafrost and tundra were present in areas of the land that were close to the glaciers and exposed to the chilly temperatures. Large, arid, and chilly grasslands developed farther away.