SIO40lecture10

SIO40lecture10 - SIO 40 Life and Climate on Earth Weds Oct....

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SIO 40 – Life and Climate on Earth Weds Oct. 20 th , 2010 Lecture 10 - The Lithosphere Joshua Tree National Park
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Outline - Earth structure - Plate tectonics - The rock cycle - Weathering - Important weathering reactions - Weathering organic carbon
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Earth Structure Earth has a layered structure. The innermost core, composed of mostly iron, is solid while the outer core is liquid. The mantle is a highly viscous layer composed of silicate minerals which differ in mineralogy and composition with depth. The upper mantle and crust are rigid. The crust is divided into about 20 crustal plates. Oceanic crust is thinner and more dense than continental crust. http://www.geology.wisc.edu/courses/g112/lecture1.html Earth structure
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Circulation of the outer core and mantle is driven by residual heat from the formation of the planet and heat that continues to be produced by radioactive decay of isotopes in the mantle. Circulation of the liquid outer core electromagnetically generates a magnetic field around Earth, with a north and south pole (see lines of magnetic force at left). At various times over Earth’s history, the polarity of the magnetic field has reversed. No one is quite sure why, although it seems to be related to the nature of the circulation in the outer core. The electro- magnetic field influences climate by mediating the interaction of Earth’s atmosphere with the solar wind. Interpreting the angle and direction of the magnetic field in ancient rocks has also provided important information about plate tectonics and the movement of the continents over time. Circulation in the outer core creates Earth’s electromagnetic field.
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Major plates of the Earth’s crust Plate tectonics The Earth’s crust is made of plates. Some plates are entirely oceanic crust, others contain both oceanic and continental crust. Plates move due to convection in the mantle. Tectonic activity (eg.
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This note was uploaded on 05/02/2011 for the course SIO 40 taught by Professor Barbeau,k during the Fall '08 term at UCSD.

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SIO40lecture10 - SIO 40 Life and Climate on Earth Weds Oct....

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