Kersantite
Kersantite is a sub-volcanic rock from the group of Shoshonite lamprophyres with biotite , hornblende and augite , in which the proportion of plagioclase in the base mass is significantly higher than the proportion of orthoclase . The green or brown horn blends usually form coarser Einsprenglinge in a fine base. In addition to the minerals already mentioned, this base material can also contain quartz , apatite and iron oxides. The biotite is very often converted into chlorite secondarily .
The name of the rock goes back to an occurrence near the place Kersanton (near Brest in Brittany ), where Kersantit veins cut through the Devonian basement. The rock name was introduced into the specialist literature in 1851 by Achille Delesse .
Chemical composition
| Oxide wt.% |
Kersantit Murgtal |
|---|---|
| SiO 2 | 55.88 |
| TiO 2 | 0.99 |
| Al 2 O 3 | 13.50 |
| Fe 2 O 3 | 1.25 |
| FeO | 4.54 |
| MnO | 0.10 |
| MgO | 9.15 |
| CaO | 3.55 |
| Na 2 O | 1.63 |
| K 2 O | 4.87 |
| P 2 O 5 | 0.77 |
| CO 2 | 0.36 |
| H 2 O + | 2.42 |
literature
- NMS Rock: Nature and origin of calc-alkaline lamprophyres: minettes, vogesites, kersantites and spessartites . Transactions of the Royal Society of Edinburgh: Earth Sciences, 74 (4), 193-227. doi: 10.1017 / S0263593300013663
- Wolfhard Wimmenauer : Petrography of igneous and metamorphic rocks. Enke, Stuttgart 1985, p. 147. ISBN 3-432-94671-6
Individual evidence
- ↑ Gustav Adolf Kenngott : Overview of the results of mineralogical research in the years 1850 and 1851. Enclosure z. Jb. Of the Imperial Geological Institute, III (4), pp. 168–169, Vienna 1853
- ↑ Wolfhard Wimmenauer: Petrography of igneous and metamorphic rocks. Enke, Stuttgart 1985, p. 148