Ontario Geological Survey the rock (bedrock); b) the deposits of sand, gravel, and till left by the glaciers; c) the mineral resources and potential; d) the energy resource potential within the rocks and soils; and e) the groundwater aquifers that contain groundwater resources. An understanding of what is at, and below, our feet is fundamental to human existence on the Earth, to understand the environment and habitats, and our ability to adapt to future changes, such as global warming. This geological knowledge is used to assess Earth resource potential, to attract investment, to ensure the health and safety of Ontario people from geo-hazards,
Gravel Gravel Gravel is a loose aggregation of rock fragments. Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel () and pebble gravel (). ISO 14688 grades gravels as fine, medium, and coarse with ranges 2 mm to 6.3 mm to 20 mm to 63 mm. One cubic metre of gravel typically weighs about 1,800 kg (or a cubic yard weighs about 3,000 pounds). Gravel is an important commercial product, with a number of applications. Many roadways are surfaced with gravel, especially in rural