Nepheline syenite

From Biocrawler, the free encyclopedia.

Nepheline syenite is a coarse crystalline igneous rock composed primarily of orthoclase alkali-feldspars, nepheline and mafic minerals such as the sodium rich pyroxenes and amphiboles. Accessory minerals are other sodium-feldspathoids, zircon, apatite and sphene. Nepheline syenites occur in Canada, Norway, Greenland, Sweden, the Ural Mountains, the Pyrenees, Italy, Brazil, China, the Transvaal region, and Magnet Cove area of Arkansas.

References

• Nepheline in Arkansas (http://www.state.ar.us/agc/nephelin.htm)
• Canada fact sheet Nepheline syenite (http://mmsd1.mms.nrcan.gc.ca/mmsd/producers/factsheets/nepheline_syenite_e.asp)
• USGS (http://vulcan.wr.usgs.gov/LivingWith/VolcanicPast/Notes/syenite.html)

Wikipedia (http://en.wikipedia.org/wiki/Main_Page) Nepheline_syenite (http://en.wikipedia.org/wiki/Nepheline_syenite) version history (http://en.wikipedia.org/w/index.php?title=Nepheline_syenite&action=history) GNU Free Documentation Lizenz (http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License) CC-by-sa (http://creativecommons.org/licenses/by-sa/2.5/)

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