Age and deformation of Early Proterozoic quartzites in the southern Lake Superior region: Implications for extent of foreland deformation during final assembly of Laurentia

Research Article| October 01, 1998 Age and deformation of Early Proterozoic quartzites in the southern Lake Superior region: Implications for extent of foreland deformation during final assembly of Laurentia Daniel Holm; Daniel Holm 1Department of Geology, Kent State University, Kent, Ohio 44242 Search for other works by this author on: GSW Google Scholar David Schneider; David Schneider 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015 Search for other works by this author on: GSW Google Scholar Christopher D. Coath Christopher D. Coath 3Department of Earth and Space Sciences, University of California, Los Angeles, California 90095 Search for other works by this author on: GSW Google Scholar Author and Article Information Daniel Holm 1Department of Geology, Kent State University, Kent, Ohio 44242 David Schneider 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015 Christopher D. Coath 3Department of Earth and Space Sciences, University of California, Los Angeles, California 90095 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (10): 907–910. https://doi.org/10.1130/0091-7613(1998)026<0907:AADOEP>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Daniel Holm, David Schneider, Christopher D. Coath; Age and deformation of Early Proterozoic quartzites in the southern Lake Superior region: Implications for extent of foreland deformation during final assembly of Laurentia. Geology 1998;; 26 (10): 907–910. doi: https://doi.org/10.1130/0091-7613(1998)026<0907:AADOEP>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Bedrock mineral cooling dates in the southern Lake Superior region establish a sharp ca. 1630 Ma thermal front that separates basement having typical post-Penokean (1750–1700 Ma) cooling ages to the north from basement having thermally reset (≤ 1630 Ma) ages to the south. The thermal front coincides spatially with an apparent deformational front in overlying post-Penokean quartzites. Subhorizontal quartzite north (Barron, northwest Wisconsin) and west (Sioux, Minnesota) of the front and highly folded quartzite south of the front (Flambeau, northwest Wisconsin) all yield ion microprobe (single-grain, single-spot) 207Pb/206Pb detrital zircon ages as young as 1750 Ma (but none younger than 1714 Ma). The new detrital zircon dates and the thermal-deformational front together with other geologic information suggest that these quartzites were all deposited between 1750 Ma and 1630 Ma. This study provides the first good structural evidence that deformation accompanied the long-recognized but enigmatic 1630 Ma low-grade, thermal-metamorphic event in the southern Lake Superior region. We interpret the strong compressional deformation exhibited in the Early Proterozoic quartzite bodies throughout much of Wisconsin to reflect foreland deformation associated with the assembly of southern Laurentia during the ca. 1650 Ma Mazatzal orogeny. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.