USGS - science for a changing world

Mineral Resources On-Line Spatial Data

Mineral Resources > Online Spatial Data > Geology > by state > Wisconsin

Powder Mill Group; Siemens Creek Volcanics

Powder Mill Group; Siemens Creek Volcanics- Dark-gray basalt and minor porphyritic andesite. Generally strongly magnetic with reversed remanent magnetism. Underlain by a thin unit of quartzose sandstone (Bessemer Quartzite).
StateWisconsin
NamePowder Mill Group; Siemens Creek Volcanics
Geologic ageMiddle Proterozoic
Original map labelYs
CommentsThis unit is labeled "Ysb" on the paper map of Sims (1992) and "Ys" in Cannon and others (1997). Unit description is from the unit labeled "Ysb" from Sims (1992).
Primary rock typebasalt
Secondary rock typeandesite
Other rock types
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Incidental
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)
Map 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
Unit references
Cannon, W.F., Kress, T.H., Sutphin, D.M., Morey, G.B., Meints, Joyce, and Barber-Delach, Robert, 1997, Digital Geologic Map and mineral deposits of the Lake Superior Region, Minnesota, Wisconsin, Michigan: USGS Open-File Report 97-455 (version 3, Nov. 1999), on-line only
Davis, D.W., and Green, J.C., 1997, Geochronology of the North American Midcontinent rift in western Lake Superior and implications for its geodynamic evolution: Canadian Journal of Earth Sciences, v. 34, pp. 476-488
Geographic coverageAshland - Iron

Show this information as [XML]

AccessibilityFOIAPrivacyPolicies and Notices

Take Pride in America logoUSA.gov logoU.S. Department of the Interior | U.S. Geological Survey
URL: http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=WIYs;0
Page Contact Information: Peter Schweitzer