Alkaline Rocks and Carbonatites of the World

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

Tibbit Hill


Occurrence number: 
Longitude: -72.42225, Latitude: 45.4076

The Tibbit Hill Formation is a group of metamorphosed volcanic rocks located in the Waterloo area of Quebec, Canada. The formation is predominantly metabasaltic, with these rocks enclosing a band of metafelsites 15 x 2.5 km. Protolith volcanics relate to the opening of the Iapetus Ocean, later metamorphosed to greenschist facies during the formation of the Appalachian foldbelt in which they reside. As a result, the primary igneous mineralogy has been wholly replaced, converting metafelsites to muscovite-quartz-albite schists. The mineralogy is consistent with rhyolitic compositions, with HFSE and REE chemistry suggesting the protoliths were peralkaline and comenditic. Agpaitic indices are <1, however this is explained by the loss of alkalis during metamorphism. Detailed major and trace element analysis can be found in Kumarapeli et al. (1989).

554 + 4/-2 Ma U-Pb zircon for “age of formation of the rock” (Kumarapeli et al., 1989)

KUMARAPELI, P.S., DUNNING, G.R., PINTSON, H. & SHAVER, J., 1989. Geochemistry and U-Pb zircon age of comenditic metafelsites of the Tibbit Hill Formation, Quebec Appalachains. Canadian Journal of Earth Sciences 26 pp 1374-1383

Fig 1. Map of the ibbit Hill Formation (Kumarapeli at al., 1989, Fig 1.)
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith