Clastic A sedimentary rock mostly composed from fragments of the parent material & deposited by mechanical transport.
Eustatic Worldwide changes in sea level.
Facies The assemblage of rock. Refers to the appearance, characteristics and peculiarities that distinguish a rock unit from its adjacent units.
Global Positioning System (GPS) A system of orbiting satellites. Are used for navigational purposes and for providing highly accurate geographic co-ordinates using hand-held receivers.
Hysteresis Describes the dependence of a physical system on its previous history. For instance, the change in sediment concentration in a stream as a result of a storm.
Multispectral A sensor which can record two or more wavelength bands
Soil pipes Just as water which flow above ground follows preferred paths such as rivers, gullies or rills, water flowing underground may do so too. We tend to visualise groundwater as a body of water just sitting there, but in fact it is likely to be moving, and it does so in different zones. Below the water table, the ground is fully saturated and water may be flowing on a regional scale. Above the water table is the zone where the ground is not fully saturated. Water may flow through the soil on a grain-to-grain basis, but it may also flow in soil pipes. Just as water flowing on the surface erodes its paths, so water flowing through this zone may erode tunnels, which can be anything from a few millimetres to several metres across. These pipes are very likely to form at layers where the permeability of the material changes - just like the pipe formed at the break between the peat and the mineral soil , but can form in other places as well - for example they may use pre-existing holes, such as those made by animals, or may be eroding back from a seepage point at the bottom end of the system'.