Ch. 17 The Earth
Terms
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- Igneous Rock
- Any rock formed from cooled and hardened magma or lava.
- Pangaea
- Supercontinent existed 250 million years ago.
- Plate Tectonic Theory
- Describes the formation, motion, and interaction of crustal plates. Combines older theories of sea-floor spreading and continental drift.
- Primary Waves (P-Waves)
- Travel through any material that squeeze and stretch rock as they pass. They are longitudinal waves. The fastest wave front and reaches areas first.
- Mantle
- Thickest layer that consists of upper and lower parts. Asthenosphere and lithosphere are in the upper part.
- Seismographs
- Detect and record seismic waves. They create different kinds of wave motions.
- Erosion
- The process by whch rock and/or the products of weathering are removed. Types of erosion include water, glaciers, wind, and deposition.
- Epicenter
- The point on Earth's surface directly above the focus.
- Frost Wedging
- A type of mechanical weathering. Water gets into cracks in rock and freezes. When it freezes it expands and further cracks rock.
- Earthquake
- A shaking of Earth's crust caused by a release of energy. Most are due to a release of strain built up at faults. Usually occur at a fault or near plate boundaries.
- Abrasion
- A type of mechanical weathering. Rocks colliding with each other. Wind and rivers supply much of the sources of this.
- Sedimentary Rock
- Any rock formed from compressed or cemented deposits of sediment.
- Exfoliation
- A type of mechanical weathering. Upward lifting of rock peels away layers of rock.
- Number of Plate Tectonics
- 7
- Formation of Hawaii
- It was formed by mantle plumes, which rise from deep inside the mantle and erupt form volcanoes as hot spots. The islands lie in a line that roughly corresponds to the motion of the Pacific Plate.
- Divergent Plate Boundary
- Most occur underneath the oceans. When two plates move apart, creating a gap between them. When this happens magma rises from the asthenosphere and cools, forming new lithospheric rock. Mid-ocean ridges form here. When the plates move apart a rift valley forms in between the ridge.
- Transform Fault Boundaries
- When rocks move horizontally past each other at faults along plate boundaries. These cause earthquakes.
- Ring of Fire
- The zone in the Pacific Ocean where volcanoes are located.
- Weathering
- The change in the physical form or chemical composition of rock materials exposed at Earth's surface.
- Seismology
- The science of measuring earthquakes.
- Continental Drift
- The movement of the continents over years. Evidence was the fossils that Wegener found and how the continents fit together like a puzzle.
- Volcano
- An opening in Earth's crust through which magma has reached Earth's surface. Most are found the edges of the Pacific Ocean where oceanic plates collide with continental plates.
- Secondary Waves (S-Waves)
- This can only travel through solids. Rock particles move at right angles to the wave movement. These are transverse waves. The slower wave front.
- Focus
- The point at which the first movement of an earthquake occurs.
- Lithosphere
- The thin outer shell of Earth, consisting of the crust and the rigid upper mantle. This floats on the asthenosphere.
- Inner Core
- Solid iron at the middle of Earth, 4300°C.
- Outer Core
- Liquid iron.
- Plants/Animals
- A type of mechanical weathering. Plant roots and animals burrow and break rock apart.
- Oxidation
- When oxygen reacts with minerals to change their composition. Generally produces rust and weakens the rock.
- Deposition
- The process of depositing sediment. Rivers and glaciers deposit materials downstream.
- Surface Waves
- When the wave front reaches the surface of the Earth. These create a rolling of the Earth's surface similar to an ocean wave, creating structure damage to buildings.
- Metamorphic Rock
- Any rock formed from other rocks as a result of heat, pressure, or chemical processes.
- Alfred Wegener
- He proved his theory that continents were together at one point. He found fossils in Africa and South America that were identical. The continents seemed to fit together like a puzzle.
- Chemical Weathering
- Rock's minerals are changed into different substances. Hydrolosis and oxidation are types of this.
- Richter Scale
- It measures the intensity of ground movements.
- Erosion
- The process by which rock and/or the products of weathering are removed.
- Crust
- Outer skin of the Earth. 100 km
- Convergent Plate Boundary
- When the plates come together. There are two types of convergent, subduction and collision. Subduction is when one plate slides underneath another. Ocean and ocean plates form volcanic island arcs. Ocean to continental plates form volcanic mountains inland. During collision two continental plates converge. This forms high mountain chains well inland.
- How Plates move
- The soft rock in the asthenosphere might circulate by convection. This could then push the plates on the lithosphere along. Also, another theory is that the plates are being moved along the lithosphere by convection currents.
- Asthenosphere
- The zone of the mantle beneath the lithosphere that consists of slowly flowing solid rock. The lithosphere floats on this.
- Mechanical Weathering
- Rock is broken into pieces by physical processes. Frost Wedging, abrasion, plants/animals, and exfoliation are all types.
- Hydrolysis
- A type of chemical weathering. A reaction of minerals with water and the minerals in rock will dissolve in water and get transported. This produces acid rain that reacts with minerals also.