LE3 .A278 2010

2010

Stanley, Cliff

Acadia University

Bachelor of Science

Honours

Geology

Earth & Environmental Sciences

This study investigates the association between a Proterozoic granitoid intrusion and anomalous Zn concentrations in soil in the West Barneys River area, Antigonish Highlands, Nova Scotia. Samples from this intrusion exhibit Zn concentrations up to 352 ppm, far exceeding the average granitoid Zn concentration of 60 ppm. Two geological surveys were undertaken to determine the source of the anomalous Zn. First, a ground magnetometer survey was undertaken to constrain the distribution of the four variably magnetic units comprising the intrusion: ( i) fine- grained alkali feldspar granite, ( ii) coarse- grained granophyric perthitic orthoclase granite, ( iii) coarse- grained quartz- alkali feldspar syenite, and ( iv) medium- grained gabbro. The magnetometer survey identified locations of highly magnetic units, and the boundaries of the intrusion. Second, because of sparse outcrop, a soil ( instead of rock) geochemical survey was carried out to determine the locations of anomalous Zn concentrations. The geochemical survey involved 320 samples sieved to - 177 μm and analyzed by aqua regia/ ICP- MS. Soil Zn concentrations exhibit a mean of 189 ppm, but range up to 1,094 ppm, and thus far exceed the global average concentration of Zn in soils ( 50 ppm). A comparison of the results of these two surveys provides insight into the spatial relationship of Zn concentrations and intrusive rocks. Anomalous soil Zn concentrations most commonly occur in or adjacent to West Barneys River in the western part of study area, an area underlain by the coarse- grained quartz- alkali feldspar syenite and fine- grained alkali feldspar granite phases. This constrains where additional research into the cause of the anomalous Zn concentrations should be undertaken.

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https://scholar.acadiau.ca/islandora/object/theses:688