1. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Chapter 8 Earth Materials and Plate Tectonics

2. Major Relief Features of the Earth’s Surface The Geologic Timescale 4.5 billion years of Earth’s history Divided into Eons, Eras, Periods Source: USGS

3. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Continents of the Past Alfred Wegener proposed first full- scale scientific theory of the breakup of one supercontinent into multiple drifting continents Pangaea: supercontinent Intact about 300 million years ago Outlines of continents fit across ocean Tectonic structures match across continents

4. Fossil remains Source: USGS

5. Earthquakes Source: USGS

6. Magnetic Striping and Polar Reversals Source: USGS

7. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Continents of the Past Satellite data show rates of plate movement from about 5 to 10 cm (2-4 inches) per year

8. Animation plate movement Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc.

9. Rocks and Minerals of the Earth’s Crust The Earth’s Interior Core: spherical central mass of the Earth composed largely of iron; consists of an outer liquid zone and an inner solid zone Mantle: rock layer of the Earth beneath the crust and surrounding the core. Crust: outermost solid layer of the Earth, composed largely of silicate minerals Oceanic crust: mafic rocks Continental crust: lower zone mafic rock, upper zone felsic (less dense) Continental crust thicker than oceanic

10. Plates of the world Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc.

11. Major Relief Features of the Earth’s Surface The Lithosphere and Asthenosphere Lithosphere: rigid outer shell of Earth, includes crust and upper mantle Asthenosphere: plastic layer below the lithosphere Lithospheric Plate: segment of lithosphere moving as a unit, in contact with adjacent lithospheric plates along plate boundaries

12. Plate Tectonics Motion of lithospheric plates drives formation of Earth’s mountains and other surface features. Convergent ocean-continental ocean-ocean continental-continental Divergent Transform Plate Tectonics: theory of tectonic activity dealing with lithospheric plates and their activity

13. Plate Tectonics Subduction: descent of the edge of a lithospheric plate under an adjoining plate and into the asthenosphere Subduction Tectonics Denser plate subducts Source: USGS

14. Convergence Source: USGS

15. Divergent Source: USGS

16. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Major Relief Features of the Earth’s Surface Relief Features of the Ocean Basins Oceanic crust 1 billion years old Ocean basins have: Midoceanic ridge Axial rift

17. Transform Boundary Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Source: USGS

18. Hot Spot Source: USGS

19. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust Igneous Rocks Igneous rock: rock formed from the cooling of magma Intrusive Igneous rock: rock formed from magma that solidifies below the Earth’s surface Visible mineral crystals Extrusive igneous rock: rock formed from magma that cooled rapidly at the surface or under the ocean Mineral crystals microscopic Magma: mobile, high-temperature molten state of rock

20. Tsunamis Source: USGS http://www.nytimes.com/interacti ve/2011/03/11/world/asia/maps- of-earthquake-and-tsunami- damage-in- japan.html??smid=fb- nytimes&WT.mc_id=WO-SM-E- FB-SM-LIN-HSP-031411-NYT- NA&WT.mc_ev=click

21. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust The Earth’s Interior Most abundant elements in crust: Oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium Minerals: naturally occurring inorganic crystalline chemical compounds Rocks: Usually composed of 2 or more minerals Rock classes: igneous, sedimentary, metamorphic

22. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust Igneous Rocks Most composed of silicate minerals: contain silicon and oxygen Felsic rock: Felsic minerals Light-colored Less dense Mafic rock: Mafic minerals Dark-colored More dense Ultramafic rock: Heavy mafic minerals Very dense

23. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust Sediments and Sedimentary Rocks Sedimentary Rock: rock formed from the accumulation of sediment Clastic—formed from rock and mineral fragments Chemically precipitated: formed by chemical precipitation from seawater or salty inland lakes Organic: formed from organic material

24. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust Sediments and Sedimentary Rocks Sandstone, deposited in layers Conglomerate Shale Chalk, a form of limestone

25. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust Sediments and Sedimentary Rocks Coal, a fossil fuel, is an organic sedimentary rock Fossil Fuels: naturally occurring hydrocarbon compounds produced from remains of organic matter enclosed in rock; examples are coal, petroleum (crude oil), and natural gas

26. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust Metamorphic Rocks Metamorphic Rock: rock altered in physical or chemical composition by heat, pressure, or other processes taking place at a substantial depth below the surface

27. Visualizing Physical Geography Copyright © 2008 John Wiley and Sons Publishers Inc. Rocks and Minerals of the Earth’s Crust The Cycle of Rock Change