Kimberlites from the Wawa area, Ontario
| Autor: | Sergei M. Sablukov, Felix V. Kaminsky, Dante Canil, Vladimir S Shchukin, Ludmila I. Sablukova |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Canadian Journal of Earth Sciences. 39:1819-1838 |
| ISSN: | 1480-3313 0008-4077 |
| DOI: | 10.1139/e02-089 |
| Popis: | Two newly discovered kimberlites from the Wawa area, Ontario, are Group-1 kimberlites in their petrographic, mineralogical, geochemical, and isotopic features. They contain mantle minerals and xenoliths of the FeTi-association (magnesian ilmenite, iron-rich olivine, orange Ti-pyrope garnet, augite, and ferroan enstatite) and of the Cr-association (chromian spinel, forsteritic olivine, purple Cr-pyrope garnets, chromian diopside, and enstatite); minerals of FeTi-association are much more abundant. Minerals of eclogitic association are absent. Both G-10 pyrope garnets and high Cr spinels typically associated with diamond are represented in the Cr-association. The average age of the kimberlites is 1097 ± 7 Ma; i.e., contemporaneous with other alkaline igneous rocks in the Wawa area. Equilibration pressures and temperatures of mantle xenoliths plot close to a 4045 mW m2 geotherm. On the basis of the Ni-in-garnet geothermometer, garnets from the Wawa kimberlites equilibrated at 8001350°C, and at least in part within the diamond stability field. It is likely that kimberlitic magma was derived from light rare earth-element-enriched asthenospheric mantle. |
| Databáze: | OpenAIRE |
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