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EARTH SCIENCE

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EARTH SCIENCE California Science Standards Standard 3 Plate tectonics Plate tectonics operating over geologic time has changed the patterns of land, sea, and ... – PowerPoint PPT presentation

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Title: EARTH SCIENCE


1
EARTH SCIENCE
  • California Science Standards

2
Standard 3 Plate tectonics
  • Plate tectonics operating over geologic time has
    changed the patterns of land, sea, and mountains
    on Earths surface
  • a. features of the ocean floor (magnetic
    patterns, age, and sea-floor topography) provide
    evidence of plate tectonics
  • b. structures that form at the three different
    kinds of plate boundaries.
  • c. properties of rocks based on the physical and
    chemical conditions, in which they formed
  • d. why and how earthquakes occur and the scales
    used to measure their intensity and magnitude.
  • e. two kinds of volcanoes one kind with violent
    eruptions producing steep slopes and the other
    kind with voluminous lava flows producing gentle
    slopes.
  • f. location and properties of volcanoes that are
    due to hot spots and the explanation for those
    that are due to subduction.

3
Tectonic Forces Convection Currents
The internal heat engine of the Earth.
  • Material in the mantle is heated by the
    radioactive core
  • it floats to the surface next to the crust
  • as it cools, it moves back down towards the core

7c Movement of matter among reservoirs is driven
by Earths internal and external sources of energy
4
Tectonic Forces Convection Currents
This continual movement (called convection
currents) causes the crust to move in plate
tectonics.
5
3a. Ocean Floor was formed by sea-floor
spreading (Magnetic patterns, age, and
sea-floor topography) provide evidence of plate
tectonics
6
3a. Sea-Floor Spreading/magnetic reversals
  • As magma rises and cools, iron and magnesium
    minerals align themselves to the Earths magnetic
    field
  • Magnetic Stripes are formed
  • The Earths magnetic field reverses polarity
  • Magnetic stripes are mirrored on each side of the
    mid-ocean ridge
  • Youngest rocks form at ridge
  • Older rocks are further from ridge
  • Oldest rocks are located at subduction zones

7
3 different kinds of plate boundaries
8
Divergent Boundaries
  • Mid-oceanic ridges/rift valley created
  • Magma enters fissures
  • Lithosphere moves away from boundary
  • New ocean crust is created

9
Convergent Boundaries
  • Subduction Zones are caused when ocean plates
    slide under each other or continental plates
  • This subduction created magma at depth which
    moves upward, pushing up the land above it.
  • This magma/lava solidifies into
    intrusive/extrusive igneous rock
  • Heat from the magma can change the rock around
    it. Rock that recrystallizes without melting
    becomes metamorphic rock..

10
Subduction Zones are formed at Convergent
Boundaries
Denser oceanic plates always subduct beneath less
dense continental plates
11
Transform Boundaries
  • Plates slip past each other
  • San Andreas Fault is a famous transform boundary
  • causes most earthquake damage

12
3c. Properties of rocks
  • Types of rocks - categorized by how formed
  • IGNEOUS - melting cooling
  • extrusive - cools quickly outside earth-small
    grained
  • intrusive - cools slowly inside - large grained
  • Sedimentary - compaction and cementing
  • Metamorphic - heat pressure

13
3d. How why of Earthquakes
  • The movement of the plates of the lithosphere
    causes stress on the rocks of the Earth
  • Friction usually holds the rocks together, the
    stress of plate movement can cause the rock to
    break.
  • Waves move out in circles from the point of
    rupture (focus)

14
Primary waves (P Waves)
  • Also known as compressional or longitudinal waves
  • They are the first waves to arrive at a location
    away from the focus.
  • They travel through all states (liquid/solid)

15
Secondary Waves
  • Also known as transverse, shear or S waves
  • They move perpendicular to the direction of
    motion
  • They can only travel through solids

16
Surface Waves
  • There are two kinds of surface waves the first
    travels along the surface in an up-and-down
    rolling motion
  • The second shakes the ground sidewise
  • They usually cause most of the damage in an
    earthquake

17
Magnitude
  • Energy released is measured with Richter Scale
  • With earthquakes over 5.5, the Richter magnitude
    is unreliable
  • Measured by amplitude of the highest wave and
    the difference in arrival time between p and
    s-waves

18
Intensity
  • Energy absorbed is measured using the Modified
    Mercalli Intensity Scale.
  • This scale measures the effects of an earthquake
    at a certain location
  • Each location may give a different reading

19
  • 3f. Volcano formation - subduction

20
  • 3f. Volcano formation -
  • can form from diverging plates, but ridge is more
    likely
  • since plates are moving apart - new crust is
    forming

21
  • 3f. Volcano formation - hot spots

22
  • 3e. two kinds of volcanoes

one kind with violent eruptions producing steep
slopes
other kind with voluminous lava flows producing
gentle slopes
23
3e. Shield Volcanoes
  • Gentle slopes
  • Erupts basaltic lava low in silica and high in
    iron and magnesium
  • Not explosive
  • Flood basalts, hot spots, spreading centers
  • Hawaiian Islands, Modoc Plateau

24
3e. Stratovolcanoes
  • Steep sides
  • Erupts andesite or rhyolite lava rich in silica
    and low in iron and magnesium
  • Can be highly explosive, produces ash falls, slow
    moving lava flows, and pyroclastic clouds
  • Mt. Lassen, Mt. St. Helens, Yellowstone

25
Standard 7 Biogeochemical cycles
  • Elements move within and throughout the Earth in
    biogeochemical cycles

26
  • 7ab carbon cycle

Notice the role of photosynthesis and respiration
27
  • 7a nitrogen cycle

Notice the role of decomposers bacteria
28

ENERGY is stored different ways -
  • The energy in coal (from solar radiation-the sun)
    is stored as chemical energy in rocks
  • Plants store solar energy by a process called
    photosynthesis
  • That energy is stored as chemical energy in
    organic (carbon based) molecules (oil and in
    plants)

29
  • 7c Movement of matter among reservoirs is driven
    by Earths internal and external sources of energy
  • Heat from the core is transferred through the
    mantle to the lithosphere because it is less
    dense
  • As the crust becomes older, it cools and
    increases in density until it subducts into the
    asthenosphere

30
  • 9b Natural Hazards of California
  • Faulting - near plate boundaries (coast)
  • Volcanoes - coastal mountains
  • Landslides - coastal areas liquefaction
  • Coastal erosion

31
  • 9C Importance of water to society,
  • the origins of Californias fresh water and the
    relationship between supply and need

32
9C the origins of Californias fresh water
  • The Sierra Nevada and Klamath Mountains are the
    major source of Californias water
  • Streams bring snow melt from the mountains in
    Northern California, where the population is
    small, to the rivers in the Great Central Valley
  • Water in Southern California, with a very large
    population, is imported from Northern California
    by the California Aqueduct and from the Colorado
    River

33
Water Quality
  • Coastal areas have a problem with saltwater
    intrusion into fresh groundwater aquifers
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