Integrated Coordinated

Science

End of Year Review

Part 1:Geology

Dynamic Earth Processes

The basalt (rock of the ocean basins) have magnetic patterns (normal or reverse polarity) due to the Earth’s polarity at the time of the rocks creation.

The oceanic ridge is the site of sea-floor spreading. New rock is formed in the center of the ridge and the rock becomes older as you move away from the ridge.

The spreading sea floor pushes up against the continental crust forming subduction zones and moves the continents (continental drift) as the sea floor spreads.

Standard 3a: Students know features of the ocean floor (magnetic patterns, age, and sea-floor topography) provide evidence for plate tectonics.

Dynamic Earth ProcessesStandard 3b: Students know the principal structures that form at the three different kinds of plate boundaries.

1. Divergent plate boundaries: Two plates move away form each other. As the plates move apart the Earth’s crust becomes thinner forming mid-ocean ridges (causing sea-floor spreading), rift valleys (tearing land apart and submarine volcanoes.

2. Convergent plate boundaries: Two plates move towards each other. As the plates crash together the form subduction zones (in which the more dense oceanic crust dives under the less dense continental crust) at which volcanic arcs, ocean trench, earthquakes and mountain ranges occur.

3. Transform plate boundaries: Two plates move laterally (Parallel slip) past each other. This movement cause earthquakes along such faults as the San Andreas Fault.

Dynamic Earth ProcessStandard 3c: Students know how to explain the properties of rocks based on the physical and chemical composition in which they formed, including plate tectonic processes.

All rocks are composed of minerals..

1. Igneous rocks are formed when molten magma or lava cools

2. Metamorphic rocks are formed by subjecting any rock type to high temperature and pressure changing the original rock.

3. Sedimentary rocks are formed when igneous and metamorphic rocks are broken into sediment by erosion followed by being compacted and cementation together.

Crystals: When magma cools slowly it allows for the formation of larger crystals. This process usually occurs inside the Earth.

When magma cools quickly crystals cannot form. This usually occurs on the Earth’s surface.

Fast cooling no crystals

Slow cooling large crystals

Dynamic Earth ProcessesStandard 3d: Students know why and how earthquakes occur and the scales used to measure their intensity and magnitude.

Earthquakes occur along plate margins where lithospheric plate move against each other. The plates build up enough energy to overcome frictional forces and slip, causing an earthquake.

The magnitude of an earthquake is measured by the Richter scale. The Richter scale measure the amplitude of the earthquake’s wave which is related to the energy released.

The intensity of an earthquake is measured by the Mercalli scale based on how the shaking felt and how much damage was done.

Dynamic Earth ProcessesStandard 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.

The violence of a volcanic eruption is based on the viscosity (how thick the liquid is) of the magma.

Temperature and chemical composition (silica content) determine the viscosity of the magma. High temperature: low viscosity, high; silica: high viscosity.

Cone shaped volcanoes are formed from highly viscous magma and erupt violently.

Shield volcanoes are formed from magma with low viscosity and have gentle slopes caused by the watery magma flowing far from the vent.

Dynamic Earth ProcessesStandard 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.

Volcanoes form at subduction zones as melted rock rises to the surface forming volcanoes. These volcanoes are concentrated at plate boundaries (edges of continents) like the ring of fire.

Volcanoes form at hot spots as the continent moves over a molten spot in the mantle. They are located in the middle of plates (away form the edges) like Yellowstone and Hawaii.

End of Part 1:Geology