The Paleoproterozoic Penokean Orogen in Northern Wisconsin is known to host multiple volcanogenic massive sulfide (VMS) deposits which are important sources of Cu, Zn, Pb, Ag, and Au. Despite known large and potentially economic VMS deposits, limited outcrop exposure has hindered detailed reconstructions of the VMS-hosting environment to guide future exploration. Zircon petrochronology can help us give a more complete understanding of the magmatic environment in which they formed. This study sampled felsic igneous rocks to determine the timing and tectonic settings of VMS deposits in the western Penokean Orogen. Samples were pulverized and heavy mineral separates were obtained by various magnetic and density separation techniques. The zircon mineral grains were imaged by cathodoluminescence and backscattered electron microscopy at Laurentian University, Canada. Zircon isotopic (U/Pb, Lu-Hf) and trace element data were analyzed via laser ablation inductively coupled plasma–mass spectrometer (LA-ICPMS). U/Pb isotopic data constrains timing of magmatism. Trace elements and Lu-Hf data constrain the tectonic setting and crustal architecture. Preliminary results have indicated two distinct VMS-forming magmatic events during the Penokean Orogeny that have similar tectonic and magmatic styles.
