Geosphere Lecture 7 0.0 / 5 ? GeographyGeosphereUniversityNone Created by: P GREENWOODCreated on: 31-12-16 16:58 Climate controls landscape evolution through: Land Surface Temperature, affecting processes & rates Sea Level, affecting energy & form of rivers, deltas, & shelves 1 of 16 Glacial / Interglacial alternations driven by Precession, Obliquity and Eccentricity 2 of 16 Thick heavy ice sheet bent lithosphere flooding on asthenosphere 3 of 16 rate of post glacial rebound function of astenossphere viscosity 4 of 16 Bedrock eroded away leds to isostatic compensation / rebound 5 of 16 Global ocean conveyer belt transporting heath to polar regions: weaker during glacial periods more active interglacial! 6 of 16 Global vegetation change drives changes in: the Hydrological cycle rates of surface erosion the global distribution of landforms 7 of 16 During LGM: much less vegetation 8 of 16 Following Schumm: kniks indicate different periods of erosion, steady state and deposition 9 of 16 River terraces are formed by alternating periods erosion and deposition (‘cut and fill’) 10 of 16 The width of the trench is equal to the width of the channel belt 11 of 16 During glacial periods upland glaciers scour the landscape and supply abundant coarse material to pro-glacial braided rivers 12 of 16 This sediment enters storage within braidplain deposits 13 of 16 Braided rivers are very dynamic rivers 14 of 16 Waimakariri river NZ: Presents a major flood hazard to 300,000 inhabitants 15 of 16 If you fix on bank river will have to move the other way… because due to high amount of depositions, alluvial ridges are created and the river migrates 16 of 16
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