30 - then so on ← Earth has 3 compositional layers •...

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Nats 101 30/01/2008 16:58:00 Earth has a magnetic field INCLINATION: parallel to flux lines: Horizontal at equator  Vertical at pole Atoms in magnetic minerals align parallel to the magnetic field when magma  cools to form seafloor rocks. PALEOMAGNETISM: preserves ancient magnetic field Normal Polarity: when negative magnetic pole is near geographic North Pole  (current status) Reverse Polarity: when positive magnetic pole is near geographic North Pole Ridge axis, positive, negative, positive, negative. Magma comes up from the earth, called the Ridge axis then during normal  polarity the closest layer to the ridge axis is positively charged igneous rock.  During reverse polarity the next layer is negatively charged igneous rock and 
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Unformatted text preview: then so on. ← Earth has 3 compositional layers • Crust, Mantle, Core ← Lithosphere • Rigid layer composed of crust and uppermost mantle • Divided into mobile tectonic plates ← Asthenosphere • Weaker layer found in upper part of mantle ← Older oceanic lithosphere destroyed at subduction zone ← The energy source is heat in the Earth ← The force involves is Gravity ← Divergent: plates move apart (i.e. Oceanic Ridges) ← Convergent: Plates move toward each other (i.e. Subduction zone) ← Transform: plates move up and down of each other (i.e. San Andrea’s fault) 30/01/2008 16:58:00 ← 30/01/2008 16:58:00 ←...
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30 - then so on ← Earth has 3 compositional layers •...

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