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Terence P. MacMichael

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B. Sc. Honours Thesis

The Origin of the Lead-Zinc-Silver Ores and Alteration of the Surrounding Granite at the Dunbrack Mine, Musquodoboit Harbour, Nova Scotia

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A small hydrothermal lead-zinc-silver deposit occurs in the Devonian adamellite of the Musquodoboit batholith, Musquodoboit Harbour, Nova Scotia. The mineralization occurs in a quartz fissure vein immediately adjacent to a fine-grained dike. Petrographic studies were undertaken on the ore minerals and surrounding granite. Microprobe analyses were done on the ore minerals, and 40Ar/39Ar dating was used to determine the age of the granite and mineralization.

Periods of movement have opened the fissure adjacent to the dike and brecciated the fissure vein. Periods of silicification have occurred throughout mineral precipitation, brecciation and supergene enrichment. The alteration surrounding the deposit is typical of hydrothermal deposits. However, a difference of 70 million years in the dates of granite emplacement and mineralization suggests that there is no genetic link between the hydrothermal fluids and the magma which formed the batholith.

Keywords:
Pages: 59
Supervisor: D. B. Clarke