F794/Unit 4 Definitions

Geology Dictionary

4.1: Water Stuff

Ground Water - Water retained in the pore spaces of rocks below the water table.

Porosity - Is the volume in the pore space.

Permeability- Is the rate at which a fluid flows through a rock.

Water Table- The surface separating the unsaturated rock above from saturated rock below.

Hydrostatic Pressure- Pressure at the point where a body of water due to the weight of rock above in the water column.

Hydraulic Gradient- Difference in hydrostatic pressure between two points divided by the distance

Aquifer- Is a body of porous and permeable rock capable of storing and yielding significant amounts of water.

Recharge Zone – The area of an aquifer open to the atmosphere allowing replenishment of water.

Aquiclude – Impermeable rock that does not transmit water.

Artesian Basin – A large synclinal confined aquifer under hydrostatic pressure.

Artesian Well – Holds water under hydrostatic pressure, which rises up the well on release.

Abstraction – Removal of water from any source.

Borehole – Drilled down into an aquifer with an  average diameter of 200mm

Well – A lined borehole with a casing which is producing water. Linings are usually steel or plastic but can be masonry and concrete.

Cone Of Depression – Occurs where there is a lowering of the water table and water around the well.

Draw Down – The height difference between water table and water level.

Dam – Structure to hold back water.

Reservoir – A body of water behind a dam wall.

Hydro Electric Power – Using water stored behind a dam to spin a turbine to generate electricity.

Renewable Resource- A source that is replenished by natural processes at rate equal or exceeding the rate of use.

Sustainable- A resource that can be used in such a way that can continue into the future.

4.2:Oil & Coal

Source Rock – Organic rich mudstone or shale containing abundant plankton that formed in a low energy, anoxic and marine environment.

Maturation- Process in which the plankton is converted into petroleum by the effects of temperature and pressure.

Migration- The moment of petroleum by the effects to temperature and pressure during burial.

Reservoir Rock- Highly porous rock and permeable rock capable of yielding significant amounts of petroleum.

Cap Rock- Impermeable rock above the reservoir rock preventing further upwards migration of petroleum.

Trap- Geological situation that concentrates petroleum in one place.

Natural Resource- Any natural resources that is useful and valuable.. 

Reserves- The amount of the resource that can be extracted at a profit using existing technology.

Blow Out- Occurs when oil gushes uncontrolled to the surface.

Primary Recovery- Where oil flows out to the surface under natural pressure and is then pumped out.

Secondary Recovery –Where water is injected below or natural gas above to maintain the pressure.

Non-Renewable- Resources that take a long time to form and cannot be replenished on human timescales.

Unstainable- Resources that are…