1�31 Notes - January 31, 2008 CitN: Nigersaurus 30'...

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January 31, 2008 CitN: Nigersaurus 30’ long, 8’ high at hips, weighed as much as an elephant (~7 tons) early cretaceous of Africa (110 Ma) super light weight delicate skull problematic for finding fossils CT scan shows inner ear, indicating muzzle held straight down for grazing 500 teeth, fell out once/month Mantle = 6600 Outer core = 8900 Inner core = 10,000 Magnetic Striping (occurs on the ocean floor symmetrically) convecting liquid outer core generates earth’s magnetic field heat from the core & radioactive decay drives mantle convection & plate tectonics making new rocks at mid-oceanic ridges. new rocks record polarity of earth’s magnetic field Magnetostratigraphy: drill a bunch of cores going up though layers analyze them to determine the pattern of magnetic polarity through time match them (like tree-rings) to the appropriate part of the known pattern for earth
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This note was uploaded on 04/03/2008 for the course GEOS 216 taught by Professor Richardthompson during the Spring '08 term at University of Arizona- Tucson.

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1�31 Notes - January 31, 2008 CitN: Nigersaurus 30'...

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