|Definitions of Geologic Terms
Alluvial deposits: Stream-sediment deposits of comparatively recent age.
Aquifer: Stratum or zone below the surface of the earth capable of producing water, as from a well.
Bedding plane: The division planes that separate the individual layers, beds, or strata of rock.
Bedrock: Solid rock underlying soils and unconsolidated materials.
Faults: Fractures in the earth's crust along which displacement has occurred. The presence of faults may be very important in the success of large-capacity wells. In general, faulting enhances the permeability of bedrock aquifers because the bedrock is broken and pulverized along the zone bordering the fault plane. This is especially true in limestone areas, where fracturing is enhanced by subsequent solution. High-capacity wells are commonly located in fault zones.
Joints: Widely spaced vertical cracks in the bedrock.
Limestone: Layered rock composed of grains of calcite cemented together; may contain fossils.
Sandstone: Layered rock composed of grains of sand cemented together.
Shale: Thin-layered rock composed of clay minerals.
Soil: Loose materials occurring between the ground surface and underlying bedrock.