An occurrence of ultrapotassic dikes in the
A brief description is presented here of a group of highly potassic, highly magnesian dikes, originally called kersantites but better-named as lamproites. These rocks may contain phenocrysts of forsteritic olivine, diopside, phlogopite, amphibole (a unique potassic magnesioarfvedsonite) and pseudole...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.2438 http://2dgf.dk/xpdf/bull27-01-02-1-8.pdf |
| Summary: | A brief description is presented here of a group of highly potassic, highly magnesian dikes, originally called kersantites but better-named as lamproites. These rocks may contain phenocrysts of forsteritic olivine, diopside, phlogopite, amphibole (a unique potassic magnesioarfvedsonite) and pseudoleucite set in a groundmass rich in phlogopite, amphibole and carbonate. A K-Ar date on phlogopite indicates an age of ca. 1200 m.y. which is similar to that of a number of other alkaline rocks in the North Atlantic region. |
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