Alkaline Rocks and Carbonatites of the World

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

Notre Dame Bay Area


Occurrence number: 
Longitude: -55.25, Latitude: 49.5

Numerous monchiquitic dykes occur along the coast and on islands in the southern part of Notre Dame Bay (Strong and Harris, 1974, Fig. 1). Titanaugite, biotite and olivine form phenocrysts and analcime is present in the groundmass and, with calcite, in ocelli. In the east of the area, particularly on Twillingate and New World Islands, the dykes contain ocelli, which may form as much as 50% of the rock, of calcite, analcime and nepheline. The more westerly dykes appear to be radial to the 5x3 km Budgells Harbour stock (op. cit., Fig. 2) which consists of gabbros including varieties with analcime and biotite. Numerous rock analyses are available.

K-Ar dating of rocks from the Budgells Harbour stock gave 139±9 and 135±8 Ma (Helwig et al., 1974) and of biotite from a lamprophyre dyke 144±12 Ma (Wanless et al., 1965).
HELWIG, J., ARONSON, J. and DAY, D.S. 1974. A late Jurassic mafic pluton in Newfoundland. Canadian Journal of Earth Sciences, 11: 1314-9. STRONG, D.F. and HARRIS, A. 1974. The petrology of Mesozoic alkaline intrusives of central Newfoundland. Canadian Journal of Earth Sciences, 11: 1208-19. WANLESS, R.K., STEVENS, R.D., LACHANCE, G.R. and RIMSAITE, R.Y.H., 1965. Age determinations and geological studies. Paper, Geological Survey of Canada, 64-17(Part 1): 1-126.
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