A paleomagnetic study of the Sudbury breccia around the northern margin of the Sudbury Igneous Complex

A paleomagnetic study of the Sudbury breccia around the northern half of the Sudbury basin shows that the Sudbury Igneous Complex (SIC) has been folded, probably during the Penokean orogeny, although some subsidence of the basin following granophyre intrusion cannot be ruled out. The paleomagnetic data suggest that the SIC was not horizontal at the time of its formation (1.85 Ga ago), and that it and the surrounding basement were deformed as a single unit by means of noncylindrical folding. The breccia carries a remanence which is thought to be due to baking by the norite unit of the SIC.