| 词条 | Rae Craton |
| 释义 |
The Rae Craton is an Archean craton located in northern Canada north of the Superior Craton. Ungava PeninsulaThe Ungava Peninsula, situated on the northeast portion of the Canadian Shield, is where the Rae Province connects with the Superior Province. The area is composed of Archean rocks (ca. 2.7-2.9 Ga) from the Douglas Harbour Domain (see Superior craton). The Rae Craton Archean rocks are overlain by Paleoproterozoic supracrustal sequences (ca. 1.8-2.1 Ga) and intruded by Paleoproterozoic diabase dykes (ca.2.0-2.2 Ga). The supracrustal rocks comprise nappes that form part of the Ungava and Labrador troughs. In the zone east of the Labrador Trough axis, the Paleoproterozoic deformation reworked the Archean rocks of the Douglas Harbour Domain, as well as the Paleoproterozoic diabase dykes. The metamorphic conditions which parallel the deformation increase from west to east and from middle amphibolite to granulite facies. U-Pb isotope analyses of zircon yield secondary ages around 1790 Ma. These results are interpreted as the age of metamorphism and indicate a reactivation of the northeastern margin of the Superior Province during a Paleoproterozoic tectono-metamorphic event, resulting from probable continental collision. (Madore, 2001). See also
References
4 : Cratons|Historical geology|Geology of the Northwest Territories|Geology of North America |
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