URBAN GEOLOGY OF THE HALIFAX REGIONAL MUNICIPALITY, NOVA SCOTIA, CANADA

With the ongoing pressures of growth and development in the Halifax Regional Municipality (HRM), many construction companies and environmental consulting groups have contacted the Nova Scotia Department of Natural Resources (NSDNR) in regards to outlining areas in the city where acid rock drainage (ARD) may be an issue in current infrastructure construction projects. However, it was soon realized that to ensure effective land use planning, a greater need existed for other geoscience information, such as an inventory of natural resources and geological hazards. To address these concerns, the NSDNR initiated a detailed (1:10 000-scale) bedrock mapping project using a GPS-enabled pocket PC to digitally capture field data. The resulting new map can be used to establish linkages between human exposure and the geographic distribution of hazardous geological materials and provides the geological framework for predicting areas of natural resources. The Goldenville and Halifax groups have been divided into several formations (Taylors Head, Beaverbank, Cunard, and Bluestone). Traditionally in the HRM, local quarries in the Taylors Head Formation have been the source for aggregate; however, as they become depleted new areas of suitable material need to be identified, and the new map provides this information. Our mapping has shown that the Cunard Formation and parts of the Beaverbank Formation contain significant amounts of sulphide-bearing minerals and as a result contribute to the ARD issues in HRM. The new map can also assist in delineating areas of elevated arsenic and mercury concentrations associated with many of the old gold mine sites in the Taylors Head Formation. In addition, the former gold districts have physical hazards including abandoned mine shafts, pits, trenches, and tailings. The ca. 380–373 Ma South Mountain Batholith in the HRM area was not systematically remapped in this project, but new exposures near the northeastern margin of the batholith resulted in adjustments to the locations of intrusive contacts. Radon occurs in areas underlain by the South Mountain Batholith where high uranium and thorium values exist, and detailed mapping has outlined areas of radon potential. In general, the new geological map is essential in land-use planning throughout HRM and provides enhanced documentation of both natural resources and geological hazards.