Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Fountain Granite

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Occurrence number: 
174-00-144
Country: 
United States
Region: 
North Carolina
Location: 
Longitude: -77.65, Latitude: 35.68
Carbonatite: 
No

A metamorphosed, peralkaline granite is exposed in a quarry 0.8 km southeast of the town of Fountain. Dykes of amphibolite, metarhyolite and basalt cut the granite, which is foliated. It consists of quartz, albite, microcline, aegirine (5.4%), sodic amphibole (4.1%), magnetite, fluorite and calcite with traces of bafertisite. The amphiboles apparently vary from ferroeckermannite and ferrorichterite to arfvedsonite and riebeckite. Rock and mineral analyses are available.

Economic: 
Crushed stone is produced from the quarry.
Age: 
K-Ar age determinations on microcline and albite gave 257 ±5 and 292 ±6 Ma, whereas a five-point Rb-Sr 'scatterchron' gave 531 ±60 Ma (Mauger et al., 1983, Table 9 and Fig. 6).
References: 

MAUGER, R.L., SPRUILL, R.K., CHRISTOPHER, M.T. and SHAFIQULLAH, M. 1983. Petrology and geochronology of peralkalic metagranite and metarhyolite dikes, Fountain Quarry, Pitt County, North Carolina. Southeastern Geology, 24: 67-89

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith