| Autor: |
Xifan Zhang, P.J. Stonier, W. R. Van Schmus, J. Loofboro, R. H. Dott, Brad S. Singer, L. G. Medaris, Daniel Holm |
| Rok vydání: |
2007 |
| Předmět: |
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| Zdroj: |
Precambrian Research. 157:188-202 |
| ISSN: |
0301-9268 |
| DOI: |
10.1016/j.precamres.2007.02.016 |
| Popis: |
Statherian siliciclastic sedimentary rocks in the southern Lake Superior region are key to understanding the evolution and stabilization of Paleoproterozoic crust in the midcontinent. Deposited during an important period of significant crustal growth, controversy exists regarding the conditions of sandstone deposition and the relations between magmatism and sedimentation. In central Wisconsin, the Hamilton Mounds inlier, although restricted in areal extent, is significant in that it reveals the existence of two separate Statherian units: an 1800–1760 Ma immature meta-arkose and a post-1760 Ma Baraboo Interval supermature quartzite. The meta-arkose is crosscut by 1762 Ma granite and contains abundant Penokean age detrital monazite grains. The younger quartzite contains detrital monazite as young as 1750 Ma and was deposited unconformably upon these older units. All units experienced 1630 Ma low-grade recrystallization and isotopic disturbance associated with the Mazatzal Orogeny. In addition, the supermature quartzite experienced K-metasomatism and brecciation at 1470 Ma, ascribed to regional-scale hydrothermal alteration related to the influence of the nearby 1470 Ma Wolf River batholith. Collectively, these data suggest an early Statherian episode of arkosic deposition and magmatism during Yavapai orogenesis, followed by a longer interval of deposition of supermature quartz arenite associated with crustal stabilization. The existence of two separate Statherian units reconciles apparent conflicts in depositional models and provides a greater understanding of the Paleoproterozoic evolution of the midcontinent. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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