Remote predictive mapping of aggregate deposits using lidar

Abstract

Remote predictive mapping techniques have been used in the Annapolis Valley, Nova Scotia, to map surficial aggregate deposits. High-resolution digital elevation models (DEMs) have been derived from light detection and ranging (lidar) data for two study sites. The lidar surveys were conducted in the spring of 2003 and 2004, ensuring that a significant number of the pulses make it to the ground or near the ground. The glacial landforms were interpreted for each site, and sediment-depth maps were calculated. The sediment depth for the Annapolis Valley site was constrained by drill hole information and pit locations. Several potential target sites have been identified using the DEM data. The North Mountain site represents a network of eskers that rest on the North Mountain Basalt, which dips 6° toward the Bay of Fundy. Sediment depth and volume were calculated for this deposit by constructing a plane representing the bedrock surface and subtracting it from the DEM. Although the landforms on the North Mountain had been previously mapped using traditional methods, details of their morphology and extent were not well resolved. The lidar provided adequate resolution to identify several new potential aggregate deposits. Follow-up fieldwork for the Annapolis Valley site has revealed that some of the targets are comprised of sand, and others do not have enough pure sand to make them economically viable at the present time.