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Rhyolite

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Ash-flow tuffs and interbedded volcaniclastic sedimentary rocks and cogenetic granite (unit Xga) exposed as inliers in southern Wisconsin. In central Wisconsin pink, flow-banded rhyolite and chert-cemented breccia inferred to be 1760 Ma.
State Wisconsin
Name Rhyolite
Geologic age Early Proterozoic
Lithologic constituents
Major
Sedimentary > Clastic > Mixed-clastic (Tuffaceous)Ash-flow tuffs and interbedded volcaniclastic sedimentary rocks and cogenetic granite (unit Xga) exposed as inliers in southern Wisconsin. In central Wisconsin pink, flow-banded rhyolite and chert-cemented breccia inferred to be 1760 Ma.
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic-ash flow)Ash-flow tuffs and interbedded volcaniclastic sedimentary rocks and cogenetic granite (unit Xga) exposed as inliers in southern Wisconsin. In central Wisconsin pink, flow-banded rhyolite and chert-cemented breccia inferred to be 1760 Ma.
Minor
Igneous > Plutonic > Granitic > Granite (Stock or pipe)Ash-flow tuffs and interbedded volcaniclastic sedimentary rocks and cogenetic granite (unit Xga) exposed as inliers in southern Wisconsin. In central Wisconsin pink, flow-banded rhyolite and chert-cemented breccia inferred to be 1760 Ma.
Comments Marshfield terrane
References

Sims, P.K., 1992, Geologic map of Precambrian rocks, southern Lake Superior region, Wisconsin and northern Michigan: U.S. Geological Survey Miscellaneous Investigations Map I-2185, scale 1:500,000.

https://pubs.er.usgs.gov/publication/i2185
NGMDB product
Counties Columbia - Green Lake - Marquette - Portage - Sauk - Waupaca - Waushara