Isobel K. Wolfson

Cassiterite and base metal sulphides have recently been discovered in Yarmouth County, southwestern Nova Scotia, in an area of folded and metamorphosed Cambro-Ordovician turbidites of the Meguma Group intruded by the monzogranitic Wedgeport pluton.

Several kinds of tin mineralization occur:

1. rare detrital cassiterite grains in a pelitic "microscour".
2. stratiform sulphide-cassiterite replacement bodies in calcareous layers.
3. sulphide-cassiterite veinlets in metasediments with restricted chlorite alteration.

Cassiterite occurs in several habits:

1. equant - in detrital, stratiform replacement bodies and veins.
2. prismatic - in stratiform replacement bodies.
3. acicular - in veins.
4. botryoidal - in stratiform replacement bodies (rare) and veins.

Geochemical analysis of drill core show that most background values in the metasediments and pluton are low compared to lithologies in the Cornish tin district and specialized ore-bearing granitoids. The sulphide-cassiterite veinlets exhibit a mineralogical and therefore geochemical variation with distance from the pluton: from Mo and W within 2 km of the pluton, to Sn about 3 to 4 km distant, to Pb and Zn about 4 to 7 km distant.

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Pages: 411
Supervisor: Marcos Zentilli