Alkaline Rocks and Carbonatites of the World

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Quenamari

stripes

Occurrence number: 
022-00-003
Country: 
Bolivia
Region: 
Cochabamba
Location: 
Longitude: -66.77, Latitude: -17.27

Ahlfeld (1966, Fig. 1_10) on his sketch map shows this occurrence to consist of two intrusions, the larger southern one being an easterly-dipping sheet extending north-south over 4 km. There is an extensive contact aureole, particularly on the eastern side, with veining and brecciation. Of four described samples one consists of 50% fresh nepheline, 20% brown amphibole, a little diopside and arfvedsonite and no feldspar. Another specimen is a 'foyaite' with 15% albite-oligoclase, 20% orthoclase, 10% nepheline, 5% sodalite, about 20% olivine, diopside and biotite. Another nepheline syenite is described as containing abundant melanocratic veins and 10% riebeckite. A boulder was found of diopsideite with about 10% chrome diopside.

Age: 
Post-Lower Palaeozoic.
References: 
AHLFELD, F. 1966. Geologische Untersuchungen in der Provinz Ayopaya (Bolivien). Neues Jahrbuch fur Mineralogie, 104, 147-71
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith