UPLIFT STRUCTURE OF THE SOUTHERN KAPUSKASING ZONE FROM 2.45 GA DIKE SWARM DISPLACEMENT

The ca. 2 Ga Kapuskasing zone, a 500-km-long belt of uplifted crust, c uts across the regional structural trend of the Archean Superior Provi nce in Canada and disrupts the continuity of 2.45 Ga Matachewan dikes that form a major swarm in its vicinity. As expressed by positive grav ity and magnetic anomalies, it appears to end about 100 km east of Lak e Superior, Until now the nature of this termination has remained obsc ure, Regional variations in paleomagnetic polarity and in the intensit y of feldspar clouding caused by magnetite exsolution are two physical properties of the dike swarm that depend upon postemplacement erosion level, They show that the Kapuskasing zone, as a narrow, fault-bounde d crustal uplift, continues, after sinistral offset, for a further 60 km to the southwest before terminating in a major cross fault, Dual ma gnetic polarity and variable levels of feldspar clouding are features found in many other Proterozoic dike smarms worldwide, and therefore, in principle, may be used to document other examples of craton respons e to tectonism.