Chapter 16 Definitions
pores – spaces or openings in rock particles
groundwater – the water that is beneath Earth’s surface
aquifer – a body of rock or sediment that stores groundwater and allows the flow of groundwater
porosity – the percentage of the total volume of rock or sediment that consists of open spaces
sorting – the amount of uniformity in the size of the rock or sediment particles shows
permeability – the ability of rock or sediment to let fluids pass through
impermeable – the inability of rock or sediment to let fluids pass through
zone of saturation – the layer of an aquifer in which the pore space is completely filled with water
saturated – a term to describe that the pores and spaces of rock are filled to capacity with water
water table – the upper surface of underground water; the upper boundary of the zone of saturation
zone of aeration – the zone that lies between the water table and Earth’s surface
capillary fringe – the process of drawing water up from the zone of saturation into the capillary fringe caused
by the adhesion of water molecules to other materials
gradient – the steepness of a slope
perched water table – water that collects above an impermeable layer that is located above the water table and
creates a second water table
recharge zone – anywhere that water from the surface can travel through permeable rock to reach an aquifer
well – a hole that is dug to below the level of the water table and through which groundwater is brought to
Earth’s surface
spring – a natural flow of groundwater to Earth’s surface in places where the ground surface dips below the
water table
artesian formation – a sloping layer of permeable rock sandwiched between two layers of impermeable rock
and exposed at the surface
caprock – the top layer of impermeable rock in an artesian formation
artesian well – a well through which water flows without being pumped
artesian spring – a formation that forms when water flows from an aquifer through natural cracks in the caprock
hot spring – groundwater that is at 37 oC and rises to Earth’s surface before cooling
travertine – step-like terraces of calcite that form when minerals are deposited when hot springs cool
mud pots – from when chemically weathered rock mixes with hot water to form a sticky, liquid clay that bubbles
at the surface
paint pots – forms when the clay in mud pots is brightly colored by minerals or organic material
geysers – hot springs that periodically erupt from surface pools or through small vents
hard water – water that contains relatively high concentrations of dissolved minerals
soft water – water that contains relatively low concentrations of dissolved minerals
cavern – a natural cavity that forms in rock as a result of the dissolution of minerals; also a large cave that
commonly contains many smaller, connecting chambers
stalactite – a suspended, cone-shaped deposit of calcite hanging from the ceiling of a cavern
stalagmite – an upward-pointing cone of calcite that forms on the floor of a cavern
column – a calcite deposit that forms when a stalactite and stalagmite meet to form a single calcite deposit
sinkhole – a circular depression that forms when rock dissolves, when overlying sediment fills an empty cavity
or when the roof of an underground cavern or mine collapses
collapse sinkhole – a sinkhole that forms when sediment below the surface is removed and an empty space
forms within the sediment causing the overlying sediment to collapse into the empty space
subsidence sinkhole – forms as rock dissolves, overlying sediments fill the cracks in the rock and a depression
forms
natural bridge – the uncollapsed rock between each pair of sinkholes forming an arch or rock
Karst topography – a type of irregular topography that is characterized by caverns, sinkholes and underground
drainage and the forms on limestone or other soluble rock