Characterizing Felsic Volcanic Rocks of the Lynne Zn-Cu-Pb Deposit, Oneida Co. Wisconsin

Abstract

The primary objective of this research was to describe the petrographic and geochemical characteristics of least-altered felsic volcaniclastic and coherent volcanic rocks that host Zn-Pb-Cu massive sulfides in the Lynne Deposit of Oneida County, Wisconsin. The Lynne deposit was first discovered in 1990 by Noranda Exploration, the current owner and leaser of property where the Lynne Deposit is located. The Lynne Deposit is one of many Volcanogenic Massive Sulfide (VMS) deposits in Northeastern and Northcentral Wisconsin. VMS deposits are created in submarine environments when high temperature hydrothermal fluids precipitate sulfide minerals. These deposits formed 1.8 to 1.9 Ga when the Pembine-Wausau Terrane collided and accreted onto the Superior Craton in the Penokean Orogeny. The felsic volcanic stratigraphy of the Lynne Deposit was described and analyzed from drillholes that intersect representative felsic units throughout the deposit stratigraphy above and below the ore horizon. Samples of these felsic volcanic strata have been petrographically and geochemically analyzed to determine the concentration of major and trace elements. These analyses will help interpret the volcanic and tectonic setting of the deposit and allow for a regional comparison between the Lynne deposit and other sulfide occurrences in the Penokean.