CHAPTER 22 Study Guide
22.1 Earth's Structure
Key Concepts
Geology is the study of planet Earth, including its composition and structure.
Earth can be divided into three main layers—the crust, mantle, and core—based on the materials that make up each layer.
Vocabulary
geologists, uniformitarianism, silicates, crust, mantle, lithosphere, asthenosphere, mesosphere, core
22.2 Minerals
Key Concepts
A mineral is a naturally ocurring, inorganic solid with a crystal structure and a characteristic composition.
The properties by which minerals can be identified include their crystal structure, color, streak, luster, density, hardness, fracture, and cleavage.
Vocabulary
rock, inorganic, streak, luster, hardness, fracture, cleavage
22.3 Rocks and the Rock Cycle
Key Concepts
Rocks are classified into three major groups—igneous, sedimentary, and metamorphic.
In the rock cycle, forces within Earth and at the surface cause rocks to change form.
Vocabulary
igneous rock, magma, lava, intrusive rock, extrusive rock, sediment, sedimentary rock, clastic rocks, metamorphic rock, foliated rocks, rock cycle
22.4 Plate Tectonics
Key Concepts
The theory of plate tectonics explains the formation and movement of Earth's plates.
Sea-floor spreading creates new oceanic crust at mid-ocean ridges. Subduction destroys old oceanic crust at subduction zones.
Plate motions are the visible part of the process of mantle convection.
There are three types of plate boundaries: divergent, convergent, and transform.
Most mountains form along plate boundaries.
Vocabulary
plate tectonics, Pangaea, continental drift, mid-ocean ridge, sea-floor spreading, subduction, trench, divergent boundary, convergent boundary, transform boundary
22.5 Earthquakes
Key Concepts
As tectonic plates move, they cause stress in the crust, which in turn produces faults and folds.
Earthquakes occur because stress forces have exceeded the strength of rock.
To measure earthquakes and pinpoint their epicenters, geologists record seismic waves using seismographs.
Most earthquakes occur along plate boundaries.
Vocabulary
earthquake, seismic waves, stress, fault, fold, focus, epicenter, P waves, S waves, surface waves, seismograph
22.6 Volcanoes
Key Concepts
Under certain conditions, small amounts of mantle rock can melt, forming liquid magma. The magma rises upward through the crust, erupting at the surface as a volcano.
Volcanoes erupt explosively or quietly, depending on the characteristics of the magma.
Most volcanoes occur along plate boundaries, or at hot spots in the crust.
The three major types of volcano are shield volcanoes, cinder cones, and composite volcanoes.
Igneous features formed by magma include batholiths, sills, dikes, and volcanic necks.
Vocabulary
volcano, magma chamber, pipe, vent, crater, caldera, hot spot, shield volcanoes, cinder cone, composite volcano, batholith, sill, dike, volcanic neck
Table of Contents