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Summary from Science Framework
Standard Set 3.
Dynamic Earth Processes
·See Framework & Standard
The earth sciences use concepts, principles, and theories from the physical sciences and mathematics and often draw on facts and information from the biological sciences. To understand Earth's magnetic field and magnetic patterns of the sea floor, students will need to recall, or in some cases learn, the basics of magnetism. To understand circulation in the atmosphere, hydrosphere, and lithosphere, students should know about convection, density and buoyancy, and the Coriolis effect. Earthquake epicenters are located by using geometry. To understand the formation of igneous and sedimentary minerals, students must master concepts related to crystallization and solution chemistry.
Because students in grades nine through twelve may take earth science before they study chemistry or physics, some background information from the physical sciences needs to be introduced in sufficient detail. From standards presented earlier, students should know about plate tectonics as a driving force that shapes Earth's surface. They should know that evidence supporting plate tectonics includes the shape of the continents, the global distribution of fossils and rock types, and the location of earthquakes and volcanoes. They should also understand that plates float on a hot, though mostly solid, slowly convecting mantle. They should be familiar with basic characteristics of volcanoes and earthquakes and the resulting changes in features of Earth's surface from volcanic and earthquake activity.
excerpt from:
Chapter Five: Earth Science, Investigation and Experimentation.
Science Framework for California Public Schools: Kindergarten Through Grade Twelve, 2004.
California Department of Education.
Acquired from online source on July 13, 2007.
· See full Framework
Standard Set 3.
Dynamic Earth Processes
·See Framework & Standard
The earth sciences use concepts, principles, and theories from the physical sciences and mathematics and often draw on facts and information from the biological sciences. To understand Earth's magnetic field and magnetic patterns of the sea floor, students will need to recall, or in some cases learn, the basics of magnetism. To understand circulation in the atmosphere, hydrosphere, and lithosphere, students should know about convection, density and buoyancy, and the Coriolis effect. Earthquake epicenters are located by using geometry. To understand the formation of igneous and sedimentary minerals, students must master concepts related to crystallization and solution chemistry.
Because students in grades nine through twelve may take earth science before they study chemistry or physics, some background information from the physical sciences needs to be introduced in sufficient detail. From standards presented earlier, students should know about plate tectonics as a driving force that shapes Earth's surface. They should know that evidence supporting plate tectonics includes the shape of the continents, the global distribution of fossils and rock types, and the location of earthquakes and volcanoes. They should also understand that plates float on a hot, though mostly solid, slowly convecting mantle. They should be familiar with basic characteristics of volcanoes and earthquakes and the resulting changes in features of Earth's surface from volcanic and earthquake activity.
excerpt from:
Chapter Five: Earth Science, Investigation and Experimentation.
Science Framework for California Public Schools: Kindergarten Through Grade Twelve, 2004.
California Department of Education.
Acquired from online source on July 13, 2007.
· See full Framework
Summary
The Earth's surface reshapes itself in a big way. Plate tectonics is the overarching conceptual understanding of how and why the Earth's surface continues to undergo large-scale deformation and change. Processes related to plate tectonics control and shape the large-scale features of the landscape - land, sea and mountains. It controls the distribution of geologic hazards such as earthquakes and volcanoes, and the original and shifted location of natural resources such as petroleum and metals. The very climate, geography and life at any particular place and geologic time is largey influenced by plate tectonics. Of the planets in the solar system are tectonically activity, Earth is the only one dominated by the motion of plates.
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Core concepts
Plate boundaries and continental margins
Standard 3b: Students know the principal structures that form at the three different kinds of plate boundaries.
Note: Types of plate boundaries (convergent, divergent and transform) may be confused with types of continental margins (active and passive).
Seafloor features and how they are related to the tectonic motion of plates
Standard 3a: Students know features of the ocean floor (magnetic patterns, age, and sea-floor topography) provide evidence of plate tectonics.
Supporting materials from Earth science
Supporting materials from other sciences and math
- Definition of tectonics and plate tectonics
- What is plate tectonics?
- Current configuration of plates
- Plate reconstructions
- Supercontinents and the Wilson Cycle
- Scientific "theory" vs. conjecture
- How the concept of continental drift evolved into plate tectonics
- Wegener's concept of continental drift
- The circumstantial fit of the continents
- Matching patterns that are now widely separated
- Wandering land better option than "polar wander"
- Plate tectonics explains how and why plate move
Note: Consistency of the usage of "plate tectonics" - force, scientific theory, object, concept, or process.
Note: Consistency of the usage of "tectonics" vs. "plate tectonics."
Note: The concepts of continental drift and plate tectonics concepts may not be clearly distinguished.
Plate boundaries and continental margins
Standard 3b: Students know the principal structures that form at the three different kinds of plate boundaries.
Note: Types of plate boundaries (convergent, divergent and transform) may be confused with types of continental margins (active and passive).
- Three kinds of plate boundaries (plate margins)
- Divergent plate margins
- Convergent plate margins
- Transform margins
Note: All "strike-slip" faults are not "transform" faults
- Two kinds of continental margins
- Active
- Passive
- Two ways of defining the internal layers of the Earth
- By composition
- By how it responds to stress (having a force exerted on it)
Seafloor features and how they are related to the tectonic motion of plates
Standard 3a: Students know features of the ocean floor (magnetic patterns, age, and sea-floor topography) provide evidence of plate tectonics.
- Key process: Seafloor spreading grows new seafloor (takes place at midocean ridges)
- Seafloor spreading
- What makes seafloor spreading take place
- Key process: Subduction consumes and destroys seafloor (takes place at subduction zones)
- Subduction
- What makes subduction take place
- How we know that plates move - direct evidence
- GPS measurements
- Visible displacement after earthquakese
- How we know that plates move - circumstantial evidence
- Topography
Seafloor slopes downward away from midocean ridges.
- Age pattern
• Seafloor is progressively older away from midocean ridges.
• Seafloor is not older than 200 million years.
• Seafloor is mostly younger than land.
- Magnetic pattern
Seafloor exhibits alternating stripes of magnetization running parallel to the midocean ridges that are in a mirror-image pattern on either side of the midocean ridge.
- Sediment thickness
• Since the seafloor is older away from the midocean ridges and has had more time to accumulate sediments, open ocean marine sediments can be thicker away from midocean ridges.
• Concepts related to the CCD disrupt this pattern.
• Sediments shed from land disrupt this pattern
- Hotspot volcanic chains (Hawaii)
Unlike "Andean" volcanic arcs over subduction zones, the age of the Hawaiian-Emperor hotspot volcanic chain are progressively older towards the Aleutians, away from the Big Island of Hawaii.
Standard 3f: Students know the explanation for the location and properties of volcanoes that are due to hot spots and the explanation for those that are due to subduction.
- Apparent polar wander
Instead of the Earth's magnetic field having wandered over time, it is the rock that moved relative to the magnetic field.
- Matching features that are separated by great distances
- Earthquakes
Standard 3d: Students know why and how earthquakes occur and the scales used to measure their intensity and magnitude.
- Volcanoes
Standard 3e: Students know there are two kinds of volcanoes: one kind with violent eruptions producing steep slopes and the other kind with voluminous lava flows producing gentle slopes.
Note: Although most explanations concentrate on the logic and development of the plate tectonic concept over time, acceptance of the potential consequences no longer depends on understanding the full explanation because we can now observe the plates actually moving.
Note: Until recently, most evidence did not directly show that plates move, but many previously unexplained observations were consistent and conveniently explained by plate tectonics. The acceptance of the plate tectonics model of how the Earth works was a little like making making a court decision - multiple and consistent lines of supporting circumstantial evidence made a strong enough case to sway the jury to accept plate tectonics.
Note: Although the magnetic pattern of the seafloor was one of the key pieces of evidence moving forward the acceptance of plate tectonics as an overarching theory, it is difficult for many to understand why it is such a compelling piece of evidence.
Evidence from the seafloor:
Note: Evidence from the seafloor, rather than land, is more illuminating. However, that evidence is limited to the past 200 million years of the Earth's tectonic history.
Evidence from the land:
Evidence from both land and sea:
Supporting materials from Earth science
- The interior of the Earth
- Layers by composition
- Layers by response to stress
- Temperature
- Convection
- Pressure
- Magnetic field
- The Earth's magnetic field
- How rocks are magnetized
- The seafloor magnetic pattern as evidence for plate tectonics
- How rocks are dated
- Using the seafloor magnetic pattern to date the seafloor
- Radiometric dating
Assigning ages in numbers of years.
- Relative dating methods
Knowing which rock is older without knowing exactly how old in numbers of years.
- Earthquakes
- What's an earthquake?
- How top locate an earthquake epicenter by triangulation
- Earthquake hazards
- Volcanoes
- Types of volcanoes and tectonic settings
Standard 3c: Students know how to explain the properties of rocks based on the physical and chemical conditions in which they formed, including plate tectonic processes.
- Types of rocks and tectonic settings
- Temperature and pressure inside the Earth
- How crystals form
- Partial melting (fractional crystallization)
- Bowen's reaction series
- Chemical solutions
- Midocean ridges
- Mid-Atlantic Ridge
- East Pacific Rise
- East African Rift
- Rift valleys
- Hydrothermal vents
- Subduction zones
- Cascadia
- Indonesia
- Tsunami
• Longest topographic features on Earth.
• All seafloor created at the midocean ridges.
• Shallowest major features in the ocean other than transition to land.
• Not all midocean ridges are located in the "middle" of the ocean.
• Not all midocean ridges exhibit rift valleys along their axis.
Supporting materials from other sciences and math
- Physics
- Density
- Buoyancy
- Convection
- Coriolis "force"
- Magnetism
- Chemistry
- Atoms and molecules
- Solutions
- Mathematics
- Graphs