68 



THE OLD SHIELDS 



180 160 



THE PRE-CAMBRIAN OLD SHIELDS 



AND NEWER PARTS OF THE CRUST OF 



^^^_^ THE EARTH 



{^;;;":;;';v The old shields, more then 600my old 



60 



;.•.•;';;.• Caledonian orogeny, about 400my old 

 ^^Jf j Hercynian orogeny about 250 my old 

 1^^ Alpine orogeny lOOmytoSOmy old 



^3300 Selected absolute dates in millions of 



years Imy) 

 1Jo7 Locolities mentioned in text 



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