Alkaline Rocks and Carbonatites of the World

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

Wentworth Pluton


Occurrence number: 
Nova Scotia
Longitude: -63.536, Latitude: 45.577

The Wentworth Pluton is a granitic intrusion located in the eastern Cobequid Highlands, Nova Scotia. It is the largest in the suite of gabbro and A-type granite intrusions in the region, emplaced into an active shear zone in the late Palaeozoic. The pluton is believed to be formed through a complex interaction between two granitic melts (sodic and calcic) and a gabbroic melt. Granites are described as syenogranites and monzogranites ranging from metaluminous to peralkaline, with both pre-, syn-, and post-gabbroic varieties present. Amphiboles include primary arfvedsonite and secondary riebeckite in sodic granites, and primary edenite and secondary actinolite in calcic granites. A number of rare REE-Y-Nb phases are found within these rocks across all stages including allanite-(Ce) and chevkinite-(Ce) in the early magmatic stages; hingganite-(Y) in the late magmatic stages; samarskite-(Y), fersmite, aesynchynite-(Y); and probable hydroxybastnäsite-(Ce) and thorite in post magmatic/hydrothermal stages. Geochemical data for accessory minerals can be found in Papoutsa & Pe-Piper (2013) and for amphiboles and whole rock data in Papoutsa & Pe-Piper (2014).

REE-Y-Nb mineralization but unknown if economic (Papoutsa & Pe-Piper, 2013)
362 ± 2 Ma U-Pb zircon (Doig et al., 1996)

DOIG, R., MURPHY, J.B. & PE-PIPER, G., PIPER, D.J.W., 1996. U-Pb geochronology of the late Paleozoic plutons, Cobequid Highlands, Nova Scotia, Canada: Evidence for late Devonian emplacement adjacent to the Meguma-Avalon terrane boundary in the Canadian Appalachians. Geological Journal 31 pp 179-188 PAPOUTSA, A.D. & PE-PIPER, G., 2013. The relationship between REE-Y-Nb-Th minerals and the evolution of an A-type granite, Wentworth Pluton, Nova Scotia. American Mineralogist 98 pp 444-462 PAPOUTSA, A.D. & PE-PIPER, G., 2014. Geochemical variation of amphiboles in A-type granites as an indicator of complex magmatic systems: Wentworth pluton, Nova Scotia, Canada. Chemical Geology 384 pp 120-134

Fig 1. Map of Wentworth Pluton (Papoutsa and Pe-Piper, 2013, Fig 1.a.)
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith