Chemistry of peralkaline phonolite dykes from the Grønnedal-Íka area, South Greenland
✍ Scribed by R. C. O. Gill
- Book ID
- 104746848
- Publisher
- Springer
- Year
- 1972
- Tongue
- English
- Weight
- 894 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0010-7999
No coin nor oath required. For personal study only.
✦ Synopsis
The chemical variation observed in a suite of fifteen, aphyrie peralkaline phonolite dykes of mid-Gardar age from the vicinity of the Gronnedal-Ika alkaline complex in southwest Greenland is discussed. From relationships in the system 5Ta20-K~O-A120a-SiO 2 it is argued that the members of the series are related by the fraetionation of feldspar approximating to Aba5Ord0An 5 in composition, along with augite and lesser amounts of other ferromagnesian minerals. The bearing of these rocks on phase equilibria in the analogous natural system is discussed, and consideration is given to the possible origins of the initial peralkaline phonolite magma.