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Depositional Model for Thor Volcanic Group

Red ball iconTHE MIDCONTINENT RIFT SYSTEM IN IOWA

 

 

Depositional Model for
Thor Volcanic Group

by R.R. Anderson

Mafic volcanic rocks (green) erupted from fissures and flowed into the subsiding central graben. In Iowa these volcanic rocks were almost exclusively confined to the central graben area.
     
  return to Stratigraphy of Thor Volcanic Group