geography rocks

how do dry valleys form?

During the ice age, underground water remained frozen while surface water melted. This forced the flow of meltwater over the surface causing erosion of valleys, when the underground water melted, the surface water moved under ground leaving dry valleys

what is freeze thaw weathering?

When water enters the cracks of rocks and freezes, expanding its volume by 9%, when it then melts and contracts it leaves the hole bigger. repeated freezing and thawing causes the rocks to crack.

what is an aquifer?

a body of permeable rock which can contain or transmit groundwater.

define curtain

a broad deposit of calcite usually formed when water emerges along a crack in a cavern

what are the properties and characteristics of limestone?

a hard grey sedimentary rock, full of (vertical) joints and (horizontal) bedding planes, in a blocky formation, can form sink holes and caves

define cavern

a large underground cave

define resurgence

a stream that emerges from underground

define stalagmite

a stumpy calcite feature formed on a cavern floor

how do stalagmites form?

a weak carbonic acid dissolves the calcium carbonate in limestone, it then seeps through into the caves below and drips down on to the floor reforming into calcium bicarbonate

how do stalactites form?

a weak carbonic acid dissolves the calcium carbonate in limestone, it then seeps through into the caves below and reforms into calcium bicarbonate while hanging down from the roof forming stalactites

define swallow hole

an enlarged joint into which water falls

define stalactite

an icicle-like calcite feature hanging down from a cavern roof

how do limestone pavements form?

areas with less joints are weathered less than area with more and after long periods of time the areas of more joints area weathered away leaving just the areas without, the gaps are called grikes and the blobs left are called clints

what is carbonation?

carbon dioxide and water react to form a weak carbonic acid. this reacts with the calcium carbonate in the limestone to form calcium bicarbonate. this wears away the rock.

what are the properties and characteristics of granite?

impermeable, igneous rocks that contain rock pits, dull spots or fissures

what are the uses of chalk areas?

pastoral farming - mainly sheep and race horses,settlements - spring line (where permeable rock meats impermeable a line of springs is formed), race horse training, quarrying - cement

what are the properties and characteristics of chalk?

permeable, sedimentary, where chalk meets an impermeable rock it forms a line of springs, gentle rolling hills

what are the uses of granite areas?

quarrying - building blocks, farming-sheep, mining - copper and tin, tourism and the extraction of china clay

what are the uses of limestone areas?

quarrying - cement and fertiliser, farming - mainly sheep and tourism - walking, camping, climbing, pot-holing and caving.

what is weathering?

the breakdown of rocks (in situ) into smaller fragments

define pillar

where a stalactite meets a stalagmite, a calcite feature that stretches from floor to ceiling in a cavern