Wausau Syenite Complex (WSC)

Region Central, North Central
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Series of potassic, Fe-enriched plutons somewhat coeval with Wolf River Batholith, dated at ~1565 Ma. Stettin nepheline syenite pluton is a REE entry in USMIN. Fluorite, REE-bearing minerals, and pyrochlore found in pegmatites cutting the Nine-Mile pluton.
Identified resources Unknown.
Production Unknown.
Status Unknown.
Estimated resources No data.
Geologic maps Sims (1992), scale 1:500,000; LaBerge and Myers (1983), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures The Wausau Syenite Complex consists of 4 intrusion. From oldest to youngest these are Stettin complex, Wausau pluton, Rib Mountain pluton, and the Nine Mile pluton. The Stetten intrusion is the most alkaline, and pegmatites carrying fluorite REE-bearing minerals and pyrochlore cut nepheline syenite. Pegmatite dikes cutting the Nine-Mile pluton carry REE minerals, including monazite, xenotime, bastnasite, and pyrochlore-group minerals, as well as abundant fluorite.
Deposits Wausau area (MRDS dep_id: 10132832).
Evidence from mineral occurrences MRDS.
Geochemical evidence Hafnium, niobium, REE, tantalum, thorium, zirconium occurrences.
Geophysical evidence No data.
Evidence from other sources No data.
Cover thickness and description Partially exposed; glacial cover in some areas.
Authors Laurel G. Woodruff.
New data needs New geologic mapping, high resolution geophysics.
Geologic mapping and modeling needs Need new geologic mapping.
Geophysical survey and modeling needs High resolution aeromagnetic and aeroradiometric coverage needed and more ground gravity data for Marathon County.
Digital elevation data needs Lidar planned; currently inadequate.