Peak-ring rim collapse accommodated by impact melt-filled transfer faults,Sudbury impact structure, Canada

Quartz diorite dikes In the footwall of the 1.85 Ga Sudbury impact structur e were emplaced within fractures formed during hypervelocity impact. The an isotropy of magnetic susceptibility of the radial Copper Cliff dike reveals a steeply dipping foliation that is counterclockwise oblique along both th e eastern and western sides of the dike, and a steeply northwest plunging l ineation. The data suggest that the Copper Cliff dike acted as a melt-fille d dextral transfer fault during collapse of the inner rim of the central pe ak ring of the impact crater to accommodate ultrahigh-strain-rate displacem ents. Peak-ring rim collapse may have caused sulfide-rich melts to be injec ted into the Copper Cliff dike, leading to the formation of large Cu-Ni-pla tinum group element deposits.