Geosphere Lecture 1 0.0 / 5 ? GeographyGeosphereUniversityNone Created by: P GREENWOODCreated on: 29-12-16 18:25 Spatial Location , height 1 of 33 Temporal Evolution over time 2 of 33 Scale km , yr etrc 3 of 33 landscapess formed by running water? Fluvial Lanscapes 4 of 33 Who created the 'cycle of erosion'? and what was it? WM Davis. Its is an evolutionary approach to landscape evolution borrowed from darwinism . (older the lanndscape the flatter it is) 5 of 33 Their are three key concepts in Davis model what are they? Potential energy, Base level and peneplain 6 of 33 What is potential energy in Davis model? Potential to do work (erode). This is determined by the land surface height above a reference level 7 of 33 What is base level in Davis model? The level to which the landscape erodes (i.e. the reference level). This is equivalent to sea level. 8 of 33 What is peneplanation in Davis model? The decline in surface elevation, gradient and relief over time as the landscape erodes 9 of 33 The modification to Davis model included which three factors? Renewed uplift , climate and Geology 10 of 33 What role did renewed uplift have in the modified version of davies model? Leads to landscape rejuvenation and creation of a polycyclic landscape (mix of young and old landforms) 11 of 33 What role did climate have in the modified version of davies model? Landscape evolution depends on the ‘intensity’ of geomorphic processes, which varies between humid, arid & glacial climates 12 of 33 What role did geology have in the modified version of davies model? Lithology and structure influence the evolution of drainage patterns 13 of 33 Name two other models of landscape evolution Penck , king 14 of 33 What is orogenic uplift? Uplift by horizontal compression and folding of earth’s crust 15 of 33 What type is the typical rate of uplift in the peruvian andes and what type of uplift is it ? 4-5 mm and orogenic 16 of 33 What type is the typical rate of uplift in the himalaya and what type of uplift is it ? 5-10 mm and orogenic 17 of 33 What type is the typical rate of uplift in the new zealand and what type of uplift is it ? 5-10 mm yr and orogenic 18 of 33 What is epeirogenic uplift? Uplift by vertical elevation of large blocks of earth’s crust 19 of 33 What type is the typical rate of uplift in the colorado and what type of uplift is it ? 0.1 mm yr and epeirogenic uplift 20 of 33 What type is the typical rate of uplift in the deccan and what type of uplift is it ? 0.015 mm yr and epeirogenic uplift 21 of 33 80-85% of the height lost due to erosion is regained by ................. of crust isostatic adjustment 22 of 33 Surface Uplift= Rock mass uplift - exhumation 23 of 33 Short-term rates (for a few thousand years) immediately after deglaciation may approach up to 100 mm yr -1 24 of 33 Name three types of weathering Physical (frost-thawing alternation) , chemical ( Karst) , Biological (roots) 25 of 33 Name four methods of erosion and transport? Water, Glaciers, Wind and mass movement 26 of 33 What is the load of a river The total amount of material transported by a river is called its ‘load’. 27 of 33 What are the three components of a river load? Dissolved load (20%), Suspended Load (70%), Bedload (10%) 28 of 33 Where will eroded sediment be re-deposited? footslope positions, in river floodplaines, intertidal zones, reach ocean sea (fans etc) 29 of 33 Names the controls on denudation ratess? Basin Relief, climate and vegegation, Lithology, tectonics & storm frequency, River incision rate, glaciers 30 of 33 Name one things which controls the height of mountains? Glacial Erosion 'signature of glacial buzzsaw 31 of 33 Global mean denudation (surface lowering) ~ 60-70 mm ka –1 32 of 33 Global mean denudation (allowing for isostatic recovery) ~ 12-14 mm ka -1 33 of 33
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