deep mantle o Geodynamo system Interactions between the outer and inner cores

Deep mantle o geodynamo system interactions between

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deep mantleoGeodynamo system Interactions between the outer and inner cores The is an open system oExchanges mass and energy with the rest of the cosmos The sun drives earth’s external engine Solar energy is responsible for our climate and weather Earth’s internal engine is powered by trapped heatOur planet is still cooling so we are losing heat Radioactivity in its interior Heat radiates from earth balancing solar input and heat from interior Meteors move mass from the cosmos to earth The Plate Tectonics System oHow does the heat energy inside the earth move and thus affect the crustal plates?It is similar to the convection process:Convection causes hot water to rise as it becomes less dense. Then it releases some of its heat, cools, and becomes more dense sinking back down. The cycle repeats. The process is called subduction – creates new crust at mid-ocean ridges and plates are subducted on the edges 
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oThe 13 major lithospheric plates African plate, Arabian plate, Somali subplate, Indian plate, Antarctic plate, Australian plate, Philippine plate, pacific plate, Juan de Fuca plate, Cocos plate, Nazca plate, South American plate, Caribbean plate, North American plate, African plate, Eurasian plateThese features the produce and recall crust are also the places that create some of most dramatic events – earthquakes, volcanoes, etc The geodynamo system oRapid motion of the liquid outer core stirs up electrical flow in the solid (iron) inner core – causing earths magnetic field (Figure 1-12)oThe magnetic field protects us from the cosmic energy that would destroy most biosystems The Geologic Record  James Hutton’s principle of uniformitarianism – geologic processes of today worked much the same way in the geologic past oSome processes are slow, like sediment accumulation on the sea flooroSome processes are rapid e.g. meteorite impact or volcanic eruption Geologic record – information preserved in rocks (geo-clues)oGrand Canyon (Slow Process)The most recent layer of sediment is about 250 million years old The rocks at the bottom are 1.7-2.0 billion years old oMeteorite Crater (Rapid Process)The explosive impact created this 1.2 km wide crater in seconds Geologic Time (Deep Time)The geologic time element is difficult for humans to perceive – we deal with time frames of 10s of years Geologic time makes nearly imperceptible rates on a human scale fast on a geologic scale 
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Plate Tectonics17:40MISSING NOTES FOR 1/18/08
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