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Structure of a Continent Figure 13-3. How are continental plates formed? Figure 13-4.

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Presentation on theme: "Structure of a Continent Figure 13-3. How are continental plates formed? Figure 13-4."— Presentation transcript:

1 Structure of a Continent Figure 13-3

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5 How are continental plates formed? Figure 13-4

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10 Continent-Ocean Collision

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12 Ocean-Ocean Collision

13 Antilles Arc

14 Subduction Zone Jump

15 Granite plutons begin deep within an orogenic belt. How do they get to the surface? Erosion and Isostatic Rebound!

16 Discovery of the “roots” of mountains:

17 “Airy”-style isostasy: density is the same, but the thickness varies (ice cube model) (Good for continental mountains)

18 “Pratt”-style isostasy: lateral density varies (Good for mid-ocean ridges)

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20 Ocean gravity map gives seafloor bathymetry.

21 World topography is mostly in isostatic equilibrium, but not always.

22 Geoid (meters), from GRACE satellite data

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32 Tectonic history of North America

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34 Eastern Terranes

35 Highlight 13-2 Tectonic history of North America: Growth of the Appalachians

36 Geometry of the Pacific – North America plates

37 Western Terranes

38 Western Terranes: The Rockies

39 But subduction is much more shallow than this picture shows!

40 Where does heating come from? Western Terranes: Basin and Range

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46 Canadian Rockies Appalachians Alps

47 Volcanism adds rock to continental volume.

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50 Hotspot volcanism often begins with a large basaltic flood.

51 Afar hotspot

52 Columbia flood basalts

53 Columbia flood basalts: Beginning of Yellowstone hotspot

54 Shape of Atlantic Ocean determined by Iceland hotspot


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