| Abstract: | Major transcurrent faults in the Superior province developed in the Late Archean at the close of the Kenoran orogeny. Reactivation of some of these faults late in the Early Proterozoic is indicated by Rb-Sr analyses of pseudotachylite from the Rainy Lake-Seine River and Quetico faults in the Rainy Lake region of Minnesota and Ontario. Fault veins of pseudotachylite and immediately adjacent country rock at two localities yielded subparallel isochrons that are pooled for an age of 1947??23 Ma. K-Ar and Rb-Sr biotite ages register earlier regional cooling of the terrane at about 2500 Ma with no evidence of younger thermal overprinting at temperatures exceeding 300??C. Accordingly, the 1947??23 Ma age is interpreted as dating the formation of the pseudotachylite. Reactivation of existing faults at this time was caused by stresses transmitted from margins of the Superior province where compressional tectonic events were occurring. -Authors |
| Genre: | Article |
| ProdID: | 70015426 |
| Citation Author: | Peterman, Z. E.; Day, W. |
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| Citation End Page: | 1092 |
| Citation Issue: | 12 |
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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: | Early Proterozoic activity on Archean faults in the western Superior province - evidence from pseudotachylite; 1989; Article; Journal; Geology; Peterman, Z. E.; Day, W. |
| Citation Start Page: | 1089 |
| Citation Volume: | 17 |
| Citation Year: | 1989 |
| Type: | citation/reference |
| Text: | Early Proterozoic activity on Archean faults in the western Superior province - evidence from pseudotachylite; 1989; Article; Journal; Geology; Peterman, Z. E.; Day, W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1989 00:00 -0600 |
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