简介:Dikeswarmsaregenerallyascribedtointrusionofmantle-sourcemagmaresultfromextension.BasicdikeswarmsaroundtheShanxi-Hebei-InnerMogoliabordersinthenorthernperipheralareaoftheNorthChinaCratoncanbedividedintofiveagegroupsaccordingtoisotopicdating:1800-1700Ma,800-700Ma,230Ma,140-120Ma,and50-40Ma.Geological,petrologicalandisotopegeochemicalfeaturesofthefivegroupsisinvestigatedinordertoexplorethevariationofthemantlematerialcompositionintheconcernedareawithtime.AndthevariousextensionalactivitiesreflectedbythefivegroupsofdikeswarmsarecomparedwithsomeimportanttectoniceventswithintheNorthChinaCratonaswellasaroundtheworldduringthesameperiod.