The Lithosphere

Unit Review Sheet

Facts and Definitions

Lesson 1: Shifting, Drifting, and Spreading

• The lithosphere describes the solid, outer layer of the Earth that includes rock and soil.
• Plate tectonics is a scientific theory that describes the movement of the plates that make up the Earth's crust.
• A scientific theory is an explanation of natural events that has been tested and supported by many observations and experiments.
• The layer of mantle that tectonic plates move on top of is called the asthenosphere.
• Isostasy is the theory that the Earth's crust floats on the mantle (the semi-fluid layer beneath it).
• Continental drift is the theory that suggests that the Earth's landmasses were once joined together in a single supercontinent called Pangaea.
• Mid-ocean ridges are the result of rift zones - places where the seafloor spreads and magma rises to create new oceanic crust.
• The lithosphere is the rigid outer layer of Earth that includes both the crust and the uppermost part of the mantle.

Lesson 2: Plate Interactions

• The areas where plates meet each other are called plate boundaries.
• In divergent boundaries, plates move apart from each other, causing rifts.
• Convergent boundaries are where plates move toward each other and crash together, causing rock to buckle, fold, or crumble.
• Transform boundaries are locations where plates slide past each other, causing fractures and faults.
• Mountains are typically formed at convergent or divergent boundaries.

Lesson 3: Rocks and Minerals

• Minerals occur naturally, are inorganic, have specific crystalline patterns, and are either chemical elements or compounds.
• Minerals can be identified based on color, luster, streak, hardness, and cleavage.
• Rocks are made up of one or more minerals and sometimes other substances as well.
• Pieces of rock and other substances that have been worn away and moved to another location by wind or water are called sediments.
• Igneous rocks are formed from cooled magma (intrusive) or cooled lava (extrusive).
• Sedimentary rocks are formed by layers of sediments that have been pressed tightly together (compacted) and/or glued together (cementation).
• Metamorphic rocks are formed from other rocks that have undergone some combination of intense heat, pressure, or chemical reaction.

Lesson 4: Seismic Waves

• Seismic waves are waves of energy that occur during an earthquake.
• Body waves are seismic waves that travel through the interior of the Earth; body waves are either primary waves (P-waves) or secondary waves (S-waves).
• Surface waves are seismic waves that create a rolling motion on the surface of the Earth.

Lesson 5: Earthquake and Volcano Research

• A volcano describes a type of mountain made from the build-up of lava.
• Magma is molten rock inside the Earth; when it reaches the Earth's surface, it is called lava.
• The four types of volcanoes are cinder cone, shield, composite cone (sometimes called stratovolcano), and lava plateau.

Lesson 6: Geologic Time

• Geologic time refers to the whole time that the Earth has existed.
• The relative age of a rock layer tells how old or young a layer is compared to other layers.
• Fossils are the preserved remains or impressions of ancient plants and animals.
• Index fossils are ones that have unique shapes, are commonly found, and lived during a narrow period of time before becoming extinct.

Lesson 7: Pedosphere and Soil

• The pedosphere is the outermost layer of the Earth, where soil is formed and used.
• The top portion of the Earth's crust where plants and crops grow is called soil.
• Stewardship means taking care of the Earth's resources and using them wisely.
• Soil erosion is the wearing away of soil by water and wind.

Final Project: Our Lithosphere and Pedosphere

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