Factors UK Physical Flashcards
Influence of precipitation
Waterlogged solids and leaching - draining of nutrients therefore unable to carry out high quality farming with high yields
Urban land use - creating even more impermeable surfaces increasing the chance of surface run off and thus flooding
Influence of geology
Tectonic processes millions of years ago has caused creation of several volcanoes which erupt to produce lava/magma which solidifies forming hard resistant igneous rock in uplands - eroded at a much slower rate than the soften sedimentary lowland rocks
Upland areas also have harder sedimentary rocks - Carboniferous limestone formed when Britain was subject to chemical and biological weathering at tropical equator - formed from biological remains
Plate movements have created large mountains of high altitude in uplands - thin solid and uneven topography, increasing gradient for flooding and much harder to create urban settlements
Influence of human activity
More impermeable surfaces
Agriculture - deforestation and chemical run-off (affecting biodiversity and increasing rates of corrosion through hydrolysis?)
Mining - landscape scarring
Settlements - deforestation and impermeable surfaces (flooding)
Forestry - conservation with carbon sinks and hydrological services (transpiration/interception)
Influence of glacial activity
U-shaped valleys in the uplands through abrasion and plucking as well as joints within igneous and metamorphic rocks being exploited through freeze thaw weathering - several ice ages over past 2.5 million years
Deposition of till/Boulder clay during glacial retreat when it loses energy and deposit is all sediment eroded (unconsolidated and prone to erosion)
Periglacial - south of England and easily erodible (by rivers through erosional processes of permafrost) forming V-shaped valleys and dry valleys are formed once permafrost melts
Influence of slope processes
Igneous intrusive batholith formed many years ago - cooled and contracted to form granite with joints developing and made it vulnerable to freeze-thaw weathering ; erosion and mass movement continued to break it down and SOLIFLUCTION alongside gravity has pulled it down forming clitter slopes
SOLIFLUCTION - active saturated/waterlogged layer of topsoil slides down weathered rock downhill
Occurs in Dartmoor which is uplands and periglacial
Sub aerial weathering adds stress to cliff faces forming scree slopes at the base of the cliff - form of mass movement where rocks pile loosely at bottom of cliff
Back when UK was in a tropical climate - large earth movements caused compacted layers of sediment to be forced upwards creating a giant chalk dome (Weld-Artois Anticline) - experienced erosion leaving two remaining chalk escarpments of the North and South Downs on either side and consists of steep scarp slope and gentler dill slope ; between chalk erosion clay vales have been exposed
What are spring line settlements?
Permeable rock on top of impermeable rock causing springs to form (like in chilterns) which is a great place for settlements - springs form at the boundary between the two
How are dry valleys formed?
In periglacial environments when the river can erode the permafrost to form V-shaped valleys and the rock is permeable so water is absorbed/infiltrated leaving behind a dry valley
Influence of tectonic activity?
Active volcanoes forced magma through earth’s crust which dolled to form igneous rock (tors/granite)
Plate collisions caused the rocks to be folded and uplifted forming mountain ranges in the uplands - resistant to erosion and relief rainfall
Intense heat and pressure caused plate collisions formed metamorphic rocks at subduction/collision zones
Plat movements meant U.K. was near the tropics and partially underwater (higher sea levels) and Carboniferous limestone formed in warm shallow seas and can be seen in Uplands
Youngest rocks are chalks and clay found in southern England - easily eroded and form lowland landscapes (periglacial - dry valleys) ; chemical/biological weathering
