The role of black shales as a source of sulfur and semimetals in magmatic nickel-copper deposits: Example from the Partridge River Intrusion, Duluth Complex, Minnesota, USA

摘要

The basal unit of the Duluth Complex (Minnesota, USA) contains Ni-Cu sulfide deposits. The S in these is thought to be derived from a sulfide-rich black shale unit known as the Bedded Pyrrhotite Unit, a stratigraphic unit within the Virginia Formation host rocks. However, the mechanism of S transfer has not been clearly established. In order to understand how this transfer occurs we have undertaken petrography and whole rock geochemistry of the rocks from the contact aureole and the basal unit.