| dc.description.abstract | The Pemberton Hills study site is situated in northern Vancouver Island, British Columbia,
and forms part of a northwest trending belt of porphyry deposits and prospects within the
Wrangellia Terrane. The study site is underlain by late Triassic to middle Jurassic Bonanza Group
volcanic rocks, with porphyry-related alteration and mineralization thought to be related to the
emplacement of the Jurassic Island Plutonic Suite (181 – 141 Ma).
Whole-rock geochemistry, high precision geochronology combined with trace element
and Hf isotope analysis of zircons from various intrusive units has led to an improved
understanding of the magmatic evolution of plutonic rocks at Pemberton Hills. The oldest unit is
a granodiorite dated at 172.34 ± 0.11 Ma. Following this is a quartz diorite with an age of 172.01
± 0.17 Ma, which overlaps with a tonalite dyke sample dated at 171.77 ± 0.13 Ma. A second
quartz diorite sample yielded the youngest reported age at 171.44 ± 0.25 Ma. These results imply
that felsic and intermediate plutonism were broadly synchronous at Pemberton Hills. [...] | en_US |
