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In this lecture we will discuss the Lithosphere, the solid part of the Biosphere http://bepratz.wikispaces.com/file/view/Lithosphere.jpg/230022458/Lithosphere.jpg 1 2 3 The upper cruse is about 100 km, compared to the 6378 km radius of Earth 4 It seems obvious to any school child looking at the globe or a map of the world that South America could fit into Africa. This idea was not so obvious to Geologists. It took a revolution in thinking, theory and observations to accept this truth. Next we’ll tell you the story of plate tectonics and how the world under our feet move 5 Paradigm shift, a topic covered in Thomas Kuhn’s famous book. Plate tectonics is a great example, as the intellectual leaders of the time were adverse to the idea of plate tectonics. Took several generations of scientists to overturn the dogma of the previous era. 6 http://www.ucmp.berkeley.edu/geology/techist.html Theory was controversial and has only been accepted the last few decades. 7 Key lines of evidence http://pubs.usgs.gov/gip/dynamic/developing.html 8 http://jan.ucc.nau.edu/~rcb7/ 9 http://jan.ucc.nau.edu/~rcb7/600_PreC_sp.jpg 10 http://pubs.usgs.gov/gip/dynamic/graphics/Fig2‐5globes.gif 11 http://jan.ucc.nau.edu/~rcb7/260_Permian_2globes.jpg 12 http://jan.ucc.nau.edu/~rcb7/090_Cretaceous_3globes.jpg 13 14 15 16 http://www.expeditions.udel.edu/extreme08/geology/images/movingplate2.gif 17 Yellow is quake zones, red is volcanos, black are plates 18 Convection cells. Heat associated with molten rock in the mantle causes convection, like movement by boiling water in a pot. Warm molten rock rises and cools as it rises. 19 20 http://www.whoi.edu/cms/images/mid_oceanridge_map_208836.jpeg Map of hydrothermal vents 21 Sea Floor Spreading eventually causes oceanic and continental plates to collide, with subduction and lifting 22 Trench Formation 23 http://www.nytimes.com/2015/06/02/science/earthquakes‐tectonic‐plates‐ collisions‐subduction.html?smid=nytcore‐ipad‐share&smprod=nytcore‐ipad&_r=0 24 25 Colliding plates are where Earthquakes occur. California is on the ground Zeros on Earth 26 27 http://www.consrv.ca.gov/cgs/rghm/psha/PublishingImages/5plusmd.jpg 28 http://www.consrv.ca.gov/cgs/PublishingImages/shaking_18x23[1].jpg 29 30 31 http://www.ucmp.berkeley.edu/geology/tecmech.html 32 33 Diatoms are made of calcium carbonite. Over geological time they form sediments that then when uplifted can form mountain ranges like the Dolomites in Italy or the Cliffs of Dover in England 34 Rocks Cycle over long geological periods and transform from sedimentary to Metamorphic to igneous. Once rocks are at the surface they weather and repeat the cycle. All this is coupled with the presence of water on the surface and the fact that Earth has plate tectonics. So the planet is geologically ‘alive’ 35 Life exists on or near the surface of the earth and that surface is affected by Geomorphology 36 37 38 39 How do river networks form. Why do they have dendritic shapes like a leaf? 40 41 What type of river networks are possible and why do branched networks tend to form? 42 Look at the land from google earth and you’ll tend to see two types of rivers formed, meandering and braided. Why are they different? 43 The coexistence of vegetation helps form meandering rivers 44 45 46 47