Contrasting types of bladed olivine in ultramafic rocks from the Archean of Labrador

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Collerson, Kenneth D., Jesseau, C. Wayne, Bridgwater, David
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1976
• Subjects: General Earth and Planetary Sciences; Nain; Hopedale
• Online Access: http://dx.doi.org/10.1139/e76-045; http://www.nrcresearchpress.com/doi/pdf/10.1139/e76-045

Exceptionally coarse grained, interlocking olivine crystals up to 1 m long occur in small lenticular ultramafic bodies within the Nain Province of Labrador. The ultramafic rocks occur in association with Archean gneisses that vary in metamorphic grade from amphibolile fades to granulite facies. Some of the interlocking textures (i.e. near Hopedale) are interpreted as relict cumulate or harrisitic growths, mimicked by olivine regrowlh during metamorphism and preserved in structurally isotropic enclaves in their host rocks. Others (e.g. near Saglek) are regarded as solely of metamorphic origin. None of the olivine growths resemble spinifex textures reported in Archean ultramafic rocks elsewhere.