| Abstract: | We have discovered a robust microcrystalline record of the early genesis of North American lithosphere preserved in the U-Pb age and oxygen isotope zoning of zircons from a lower crustal paragneiss in the Neoarchean Superior province. Detrital igneous zircon cores with ??18O values of 5.1???-7.1??? record creation of primitive to increasingly evolved crust from 2.85 ?? 0.02 Ga to 2.67 ?? 0.02 Ga. Sharp chemical unconformity between cores and higher ??18O (8.4???-10.4???) metamorphic overgrowths as old as 2.66 ?? 0.01 Ga dictates a rapid sequence of arc unroofing, burial of detrital zircons in hydrosphere-altered sediment, and transport to lower crust late in upper plate assembly. The period to 2.58 ?? 0.01 Ga included ???80 m.y. of high-temperature (???700-650 ??C), nearly continuous overgrowth events reflecting stages in maturation of the subjacent mantle root. Huronian continental rifting is recorded by the youngest zircon tip growth at 2512 ?? 8 Ma (??? 600 ??C) signaling magma intraplating and the onset of rigid plate behavior. This >150 m.y. microscopic isotope record in single crystals demonstrates the sluggish volume diffusion of U, Pb, and O in zircon throughout protracted regional metamorphism, and the consequent advances now possible in reconstructing planetary dynamics with zircon zoning. ?? 2008 The Geological Society of America. |
| Genre: | Article |
| ProdID: | 70031916 |
| Citation Author: | Moser, D. E.; Bowman, J. R.; Wooden, J.; Valley, J. W.; Mazdab, F.; Kita, N. |
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| Citation End Page: | 242 |
| Citation Issue: | 3 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geology |
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| Citation Number Of Pages: | 4 |
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| Citation Search Results Text: | Creation of a continent recorded in zircon zoning; 2008; Article; Journal; Geology; Moser, D. E.; Bowman, J. R.; Wooden, J.; Valley, J. W.; Mazdab, F.; Kita, N. |
| Citation Start Page: | 239 |
| Citation Volume: | 36 |
| Citation Year: | 2008 |
| Type: | citation/reference |
| Text: | Creation of a continent recorded in zircon zoning; 2008; Article; Journal; Geology; Moser, D. E.; Bowman, J. R.; Wooden, J.; Valley, J. W.; Mazdab, F.; Kita, N. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1130/G24416A.1 |
| Date Other: | Tue, 1 Jan 2008 00:00 -0600 |
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