Summary Ch8



Summary Ch8
AP Environmental Science
Chapter 8
Earth Systems
Learning Objectives Summaries
Module 24: Mineral Resources and Geology
 Describe the formation of Earth and the distribution of critical elements on Earth.
Earth formed from cosmic dust in the solar system. As it cooled, heavier elements, such as iron,
sank toward the core, while lighter elements, such as silica, floated toward the surface. These
processes have led to an uneven distribution of elements and minerals throughout the planet.
Define the theory of plate tectonics and discuss its relevance to the study of the
Earth is overlain by a series of plates that move at rates of a few millimetres per year. Plates can
move away from each other, move toward each other, or slide past each other. One plate can be
subducted under another. These tectonic processes create mountains, earthquakes, and volcanoes.
 Describe the rock cycle and discuss its importance in environmental science.
Rocks are made up of minerals, which are formed from the various chemical elements in Earth’s
crust. The processes of the rock cycle lead to the formation, breakdown, and recycling of rocks.
Module 25: Weathering and Soil Science
Understand how weathering and erosion occur and how they contribute to element
cycling and soil formation.
Physical weathering is the mechanical breakdown of rocks and minerals while chemical
weathering is a result of chemical reactions. Both occur as a result of natural processes and can
be accelerated by human activities. Erosion is the physical removal of rock fragments and
weathering products that are subsequently deposited elsewhere.
 Explain how soil forms and describe its characteristics.
Soil forms as a result of physical and chemical weathering of rocks and the gradual accumulation
of organic detritus from the biosphere. The factors that determine soil properties are parent
material, climate, topography, soil organisms, and time. The relative abundances of sand, silt,
and clay in a soil determine its texture.
Describe how humans extract elements and minerals and the social and environmental
consequences of these activities.
Concentrated accumulations of minerals from which economically valuable materials can be
extracted are called ores. Ores are removed by surface or subsurface mining operations. Surface
mining generally results in greater environmental impacts, whereas subsurface mining is more
dangerous to miners. With the exception of coal mining, legislation directly related to mining
does not address most environmental considerations.
Hot Spot
Plate tectonics
Tectonic cycle
Divergent plate boundary
Seafloor spreading
Convergent plate boundary
Transform fault boundary
Seismic activity
Fault zone
Pichter scale
Rock cycle
Igneous rock
Intrusive igneous rock
Extrusive igneous rock
Sedimentary rock
Metamorphic rock
Physical weathering
Chemical weathering
Acid precipitation
Acid rain
Parent material
Soil degradation
O horizon
A horizon
E horizon
B horizon
C horizon
Cation exchange capacity
Base saturation
Crustal abundance
Strip mining
Mining spoils
Open-pit mining
Mountaintop removal
Placer mining
Subsurface mining

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