1. APES Ms. Tooker 2015

2.   Geologic time scale  Plate tectonics  Earthquakes  Volcanism  Seasons  Solar intensity  Latitude/longitude Earth Science Concepts

3.   Two time scales are used to measure the age of Earth.  Sequence of layering of the rocks (strata) and evolution of life  Radiometric time scale-natural radioactivity of chemical elements in rocks Geologic Time Scale

4.   Organized into various units according to events that took place in each period  Usually separated by major geologic or paleontological events (mass extinctions)  Largest unit of time- eon  Eon  Eras  Periods  Epochs  Stages Geologic Time Scale

5. 

6. 

7.   Rock layers (strata) are laid down in succession with each strata representing a “slice” of time.  The principle of superposition- any given layer is probably older than those above it and younger than those below it. Key Principles of the Geologic Time Scale

8.   NOOOO!!!  Layers are often eroded, distorted, tilted, or uneven  Layers laid down at the same time in different areas can have entirely different appearances  A layer from any given area represents only part of Earth’s history Is the Geologic Time Scale perfect??

9.   Formed 4.6 billion years ago  Third planet from the sun in the solar system  Only planet known to support life Earth Structure

10.   Biosphere- includes all forms of life (plants and animals) both on land and in the sea  Hydrosphere- includes all forms of water (fresh and saltwater, snow, ice)  Lithosphere- includes the outermost shell of the planet (crust and upper mantle), approximately 62 miles thick Earth Structure

11.   Makes up 0.5% of Earth’s total mass  Floats on top of the mantle  Oceanic crust  From Earth’s surface to 7 miles down  Relatively cold  Rocky  Brittle  Fractures easily in earthquakes Crust

12.   Extends from Earth’s surface to 20-30 miles down  Appears stratified (layered)  Composed of volcanic, sedimentary, and granite- type rocks  Older areas may be metamorphic Continental Crust

13.   Most of Earth’s mass  Composed of iron, magnesium, aluminum, and silicon-oxygen compounds  Over 1800˚F  Mostly solid  Upper third (asthenosphere) is more plastic-like Mantle

14. 

15. 

16.   Continental drift theory- 1915, Alfred Wegener  All present-day continents originally formed one landmass (Pangaea).  Based on:  Fossilized tropical plants discovered beneath Greenland’s icecaps  Tropical regions on some continents has polar climates in the past, based on paleoclimatic data  The continents fit together like pieces of a puzzle Plate Tectonics

17. 

18.   Seafloor Spreading Theory- 1960s  Alternating patterns of magnetic properties were discovered in rocks found on the seafloor.  Dating of the rocks indicated that as one moved away from the ridge, the rocks became older.  New crust was being created at volcanic rift zones. Plate Tectonics

19. 

20.   Earth’s plates float and move on the viscous asthenosphere  Subduction zones- where two plates meet and move towards each other Plate Tectonics

21.  Earth’s Major Plates

22.   Occur where plates slide past each other.  Friction and stress buildup from the sliding plates and earthquakes occur  Example: San Andreas Fault (Pacific Plate and North American Plate) Transform Boundaries

23.   Occur where two plates slide apart from each other with the space that was created being filled with molten magma from below.  Can create massive fault zones in the oceanic ridge system-frequent oceanic earthquakes  Example- Mid-Atlantic Ridge and the East Pacific Rise Divergent Boundaries

24.   Occur where two plates slide toward each other, forming a subduction zone (one plate moving under the other) or an orogonic belt (two plates collide and compress) Convergent Boundaries

25.   Subduction zone- basaltic oceanic crust is more dense than granite continental crust.  Examples- deep ocean trenches, stratovolcanoes and Volcanic Mts. on Land. ex.  Cascade Mountains in the Pacific Northwest US Oceanic-Continental Convergence

26.   An island arc (curved chain of volcanic islands rising from the deep seafloor and near a continent)  Created by subduction processes  Examples- Japan, Aleutian Islands in Alaska Oceanic-Oceanic Convergence

27.   Mountain ranges are formed when plates collide  Earth’s crust is compressed and pushed upward  Examples- Himalayas Continental-Continental Convergence

28. 

29.   Two classes of seismic waves: body waves and surface waves  Body waves travel through the interior of Earth  Two types of body waves:  P waves  S waves Earthquakes

30.   P waves:  Travel through Earth  Caused by expansion and contraction of bedrock Earthquakes

31.   S waves:  Produced when material moves either vertically or horizontally  Travel only within the uppermost layers of Earth (along its surface) Earthquakes

32.   Surface Waves:  Produce rolling and/or swaying motion and are slower than P or S waves.  Cause ground motion and damage. Earthquakes

33.   The severity of an earthquake depends upon:  The amount of potential energy that has been stored  The distance the rock mass moved when the energy was released  How far below the surface the movement occurred  The makeup of the rock material Earthquakes

34.  The Richter Scale

35.  Tsunamis  A series of waves created when a body of water is rapidly displaced, usually by an earthquake  Generated when plate boundaries move abruptly move  Subduction-zone-related earthquakes generate the majority of all tsunamis

36. 

37.   Active volcanoes produce magma (melted rock) at the surface.  About 95% of volcanoes occur at subduction zones and mid-oceanic ridges  About 5% occur at hot spots  Produce ejecta (lava rock and/or ash)  Molten lava  Toxic gases- steam, carbon dioxide, sulfur dioxide Volcanoes

38.  Atmospheric Effects of Volcanoes

39.  General Volcano Structure

40.   Factors that affect the amount of solar energy at the surface of Earth:  Earth’s rotation (once every 24 hours)  Earth’s revolution around the sun (once per year)  Atmospheric conditions Seasons, Solar Intensity, and Latitude

41.  Summer Solstice  Sun rises higher in the sky  Stays above the horizon longer  The sun’s rays strike the ground more directly (less of an angle)

42.   Northern hemisphere is titled away from the sun  The sun rises lower in the sky  Stays above the horizon for a shorter period of time Winter Solstice

43.   Earth is closest to the sun during the Northern Hemisphere winter (Dec.-Feb.)  Earth is farthest away during the Northern Hemisphere summer (June-Aug.)  Seasons are NOT caused by Earth’s distance from the sun!!  Seasons are created by the angle of sunlight hitting the Earth.