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Continental Drift

Oceanic Ridges

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Deep Sea Trenches

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Sea Floor Spreading (SFS) proposed in early 1960’s How do we test SFS?

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Figure 2.17 Figure 2.18

Fig. 12-11, p.342

SFS: why it looks good:Distribution of Igneous Activity & Seismic EventsAge Dating basalt and marine fossilsSediment ThicknessMagnetic Anomalies, Heat FlowSequence of Sediments off Passive Continental Margins

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Plate TectonicsFigure 2.23

3 General types of Plate Boundaries

Divergent

ConvergentMany variations

Transcurrent orTransform

Figure 2.24

Divergent

Figure 2.25

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Convergent: Oceanic to Continental

Convergent: Oceanic to OceanicConvergent: Continental Collision

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Figure 2.23

Transform or Transcurrent

Transform

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Global Seismic Activity over ~20 year span

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