Geology Content from Frameworks
The content listed below comes directly from the State Frameworks. All statements are included (even
though many of them are essentially the same) unless the statements were identical. It is important for both
teachers and students to be familiar with the language of the standards and the frameworks. If it is stated in a
framework, then it can possibly be tested.
General
 Some changes in the earth’s surface are abrupt (such as earthquakes and volcanic eruptions) while other
changes happen very slowly (such as uplift and wearing down of mountains, deposition, weathering, and
erosion).
 The surface of the earth changes over time. Earth surface changes may be abrupt or gradual-constructive or
destructive.
 The lithosphere, top layer of the Earth is broken into plates. These plates are in constant motion. The
motion of these plates results in major geologic events like earthquakes, volcanic eruptions, and even
mountain building. These major events, along with weathering and erosion change the surface of the earth.
Layers of the Earth
 The earth is layered with a partly molten, metallic core; a mantle that though solid, is hot enough to flow;
and a colder, rigid lithosphere.
 The earth is layered with a lithosphere (crust and uppermost mantle), convecting mantle, and a dense
metallic core.
 Each layer differs in composition, density, and temperature.
 The layers of the earth, crust, core, and mantle have different physical properties.
 Temperature and density increases as depth increases.
 The composition of the earth changes with depth and layers.
 The crust is the upper part of the rigid lithosphere and is of different composition under land as opposed to
the ocean floor.
 Below the rigid lithosphere, the mantle consists of hot rock of tar-like consistency, which slowly moves or
flows.
 The outer core is molten and the inner core is a dense solid.
 The lithosphere is divided into separate plates which move very slowly in response to the mantle.
 Heat from the mantle and core creates convection currents.
 The mantle is solid but capable of flow (like hot asphalt or fudge). Only under special conditions (at hot
spots and along plate boundaries) does the mantle or crust melt to make magma, which may then rise to the
surface to make a volcanic eruption.
 The Earth’s inner core is a solid sphere composed mostly of iron. It is about 2,400 kilometers (1,500mi) in
diameter and is believed to be as hot as 6650° C (12000°F). This heat is probably generated by the
radioactive decay of uranium and other elements. The inner core is bordered by a liquid outer core that is
4700°C (8500°F).
 Surrounding the outer core is the mantle, which is composed of hot, molten rock called magma. The
churning of the magma, caused by the heat rising from the core, generates pressure on the Earth’s surface
layer, or crust.
 The crust is very thin compared to the other layers, ranging in thickness from only about 3.2 kilometers
(2mi) in some areas of the ocean floor to some 121 kilometers (75mi) deep under mountains.
 The crust is composed of plates on which the continents and oceans rest. These plates move slowly on the
magma beneath them. The plates may move apart, collide, and slide past each other, resulting in
phenomena as hydrothermal vents, volcanoes, and earthquakes.
1
Geology Content from Frameworks
Rocks & Minerals
 Geologists can date rock layers within a bedrock by observing the sequence of its layers and studying the
fossils present in each layer.
 Fossils, the remains of organisms preserved in sedimentary rocks, are part of the evidence scientists use to
infer changing conditions at the Earth’s surface through time
 Rocks are composed of minerals. Minerals are the building blocks of rocks.
 Minerals can be identified by their physical properties.
 Rocks at the Earth’s surface weather, forming sediments that are buried, then compacted, heated, and often
recrystallized into new rock.
 Many materials used by people come from rocks and minerals.
 Rocks can be distinguished into many different types, based on their origins and compositions.
 Rocks and minerals are not the same thing; rocks are composed of minerals which are naturally existing
chemical compounds.
 Rocks and minerals are naturally occurring substances that are usually crystalline and solid.
 Rocks are the building blocks of the Earth's crust. We can identify the minerals present in rocks. We can
learn about the process of formation of rocks by looking at their textures (or grain sizes, shapes, and
arrangement).
 Hardness is tested by scratching.
 Rocks are classified based on how they formed and their mineral composition.
 Almost every product we use in daily life contains depends on minerals that have to be mined.
 The rock cycle explains how one rock type can be transformed into another. This process is continuing
today.
 A rock is an aggregate of one or more minerals There are three basic categories of rocks: Igneous (or
cooled from hot molten lava or magma) - ex. granite, basalt Sedimentary (or fragments laid down by water
or wind) - ex. sandstone, shale, limestone Metamorphic (or rocks changed by heat and or pressure) - ex.
gneiss, schist, slate, marble
 Any rock type can undergo weathering to form sediment. Igneous, metamorphic and sedimentary rocks
undergo weathering.
 Sedimentary rocks are formed by the ongoing deposition of rocks and other sediments that are cemented
together.
 Usually after burial, the deposited sediment undergoes lithification (the processes that turn it into a rock).
This includes cementation and compaction.
 Sedimentary rocks are made from sediment. Sediment is loose particulate material (clay, sand, gravel,
shells, plant fragments, etc.). Sediment may be transported and deposited by moving water, wind, or ice.
Sediment becomes compacted and cemented to form sedimentary rock. We can interpret the process of
formation of sedimentary rocks by looking at their grain size and shape (i.e., their texture). Fine-grained
sedimentary rocks were deposited by still, quiet, low-energy water. Coarse-grained sedimentary rocks were
deposited by rapidly-moving, high-energy water indicate a long distance of transportation during which the
grains of sediment rolled and tumbled along, which wore down any sharp corners. Angular grains in a
sedimentary rock indicate a short distance of transportation.
 If the sedimentary rock is buried deep in the crust under more and more sediment, often due to plate
tectonic movements, the heat and pressure causes metamorphism to occur. This transforms the sedimentary
rock into a metamorphic rock.
 Magma cools and crystallizes to form igneous rock.
 Magma is hot, molten rock beneath the surface of the Earth. Lava is hot, molten rock which has flowed out
onto the surface of the Earth. Magma may cool within the Earth's crust to form igneous rocks. But lava
cools much more quickly because it is on the Earth's surface where temperatures are much lower than they
are deep within the Earth. Cooling rates influence the texture of the igneous rock: Quick cooling = fine
grains Slow cooling = coarse grains
2
Geology Content from Frameworks
 Igneous rocks are "fire-formed". They crystallized from hot, molten lava or magma as it cooled.
 Igneous rocks are dominated by silicate minerals.
 Igneous rock undergoes weathering (or breakdown) to form sediment. The sediment is transported and
deposited somewhere (such as at the beach or in a delta, or in the deep sea).
 Igneous rocks are classified (or named) based on their composition (which minerals they contain) and
texture (or the size of the mineral grains). The texture is a result of the process of formation of the igneous
rocks. A variety of textures are present in igneous rocks. For this exercise, we will only consider a few
textures (and their process of formation): Fine-grained (produced by quick cooling and crystallization of
lava), Coarse-grained (produced by slow cooling and crystallization of lava), Glassy (produced by
instantaneous cooling of lava – so fast that there is no time for minerals to crystallize), and Vesicular
(contains holes made by gas bubbles in a quick-cooling or instantaneous-cooling lava). Now and then, you
may see an igneous rock with a mixture of grain sizes – larger minerals surrounded by smaller minerals.
This indicates a complicated process of formation of the igneous rock, in which the magma initially cooled
very slowly, and then the magma erupted as lava and cooled quickly. An igneous rock with mixed grain
size indicates a mixed cooling history.
 Igneous rocks can undergo metamorphism (as a result of heat and pressure) to form metamorphic rocks.
 As the metamorphic rock is buried more deeply, temperatures and pressures continue to rise. If the
temperature becomes hot enough, the metamorphic rock undergoes melting. The molten rock is called
magma. This completes the cycle.
 Metamorphic rocks formed as a result of changes to other types of rocks. The processes of formation of
metamorphic rocks involve changes caused by heat and pressure associated with deep burial and tectonic
pressures (caused by moving tectonic plates). Those changes, called metamorphism, include compaction
(which makes the rock become more dense and makes the grains move closer together), and
recrystallization (the growth of new minerals). In other words, metamorphism causes changes in the texture
and minerals of rocks. As shale is subjected to increasing heat and pressures, the clay minerals in it are
recrystallized to form micas (such as muscovite and biotite). As heat and pressure increase, the mica grains
increase in size. Pressure causes the minerals in a metamorphic rock to become oriented perpendicular to
the direction of force. The mica grains (such as muscovite and biotite) become aligned parallel with one
another to form a new texture called foliation. Rocks with foliation include slate, schist and gneiss.
Metamorphic rocks which lack mica minerals are called non-foliated, and they have an even, granular
texture with no aligned minerals. Non-foliated metamorphic rocks include marble and quartzite.
 The Stone Mountain granite is a relatively small granite pluton that covers an area less than a county in
size.
Plate Tectonics
 The Earth is divided into layers. The outermost layer of the Earth is called the lithosphere.
 Lithospheric plates on the scales of continents and oceans constantly move.
 The lithosphere of the Earth is broken up into tectonic plates. These tectonic plates are moving.
 At the edges or boundaries of the plates, the earth's crust is in motion.
 The theory of plate tectonics connects the evidence for the formation, movement, and destruction of the
plates.
 The movement of the tectonic plates either helps to build or destroy the surface of the Earth. In other
words, the movement of these plates causes major events on the Earth’s surface.
 Lithospheric plates on the scales of continents and oceans constantly move. At the boundaries of the plates,
the earth’s crust is in motion.
 Some changes in the earth’s surface are abrupt (such as earthquakes and volcanic eruptions) while other
changes happen very slowly (such as large-scale plate movement and wearing down of mountains)
 Heat sources near the earth’s surface can produce geologic features not located at major plate boundaries.
3
Geology Content from Frameworks
 [misconception-world map is unchanging or a major change will happen in my lifetime] Moving plates
cause major changes in a world map over tens of millions of years.
 At the boundaries of plates, the earth’s crust is in motion. There are three major types of plate boundaries:
convergent, divergent, and transform.
 At divergent plate boundaries such as the mid-Atlantic ridge, new ocean floor is created.
 At convergent plate boundaries known as subduction zones, a trench and deep earthquakes mark the zone
where a slab of oceanic lithosphere descends into the mantle, and volcanoes and mountain ranges form on
adjacent land.
 When continental crust meets continental crust at a convergent boundary, a collision occurs, resulting in
folds, faults, and high mountains.
 Transform boundaries are where plates slide past each other. They connect other plate boundaries and are
characterized by earthquakes.
 Moving plates cause major changes in a world map over tens of millions of years.
 Pangaea was the most recent of a succession of supercontinents that have formed and broken up over time.
 Major geological events, such as earthquakes, volcanic eruptions, and mountain building, result from these
plate motions.
 Earthquakes and volcanoes often occur along the boundaries between lithospheric plates.
 The mantle is solid but capable of flow (like hot asphalt or fudge). Only under special conditions (at hot
spots and along plate boundaries) does the mantle or crust melt to make magma, which may then rise to the
surface to make a volcanic eruption.
 Earthquakes occur along plate boundaries and are a result of tectonic plate movement.
 Earthquakes can occur in all parts of the United States; however, those in California usually stronger and
more frequent.
 Most earthquakes are the result of tectonic plate movements.
 Earthquakes represent sudden breaks in crust continuously stressed by plate movement. Gradually over
time, the same movements result in major crustal features.
 Most earthquakes happen near the boundaries of tectonic plates, where the plates either spread apart or grind
together. Along plate boundaries, the Earth’s lithosphere fractures along faults. As plates move, blocks of crust
shift along the faults. There are various kinds of faults.
 The San Andreas is a "strike-slip" fault. Along this fault, the plates slide past each other. The other major family
of faults is called "dip-slip" faults where blocks of crust either push together or pull apart causing one block to
slide either up or down a sloped fault plane.
 Stress builds up in fault zones when crustal blocks stick together causing the rocks on either side of the fault to
store the building stresses until the rocks move suddenly along the fault, releasing the stresses. This causes
seismic waves to move into the surrounding rock.
 Seismic energy travels through the crust in the form of waves. There are two basic kinds of seismic waves: body
waves and surface waves. Body waves travel outward in all directions, including downward, from the quake's
focus. Surface waves are only found in the upper layers of crust and travel like ripples on the surface of water.
Surface waves are slower than body waves. Following an earthquake, the body waves strike first. The fastest
kinds are the primary waves, or P-waves. Then the secondary, or S-waves, arrive. Finally, the surface waves
strike.
 Tsunamis are most commonly the result of earthquakes associated with movement of oceanic crust.
 Tsunamis can occur on all Pacific shorelines.
 Tsunamis are seismic ocean waves caused by large earthquakes and landslides that occur near or under the
ocean in oceanic crust. Tsunami waves are unlike typical ocean waves generated by wind, storms, or tides.
They do not "break" like the curling, wind-generated waves. Even "small" tsunamis (for example, 6 feet in
height) are associated with extremely strong currents, capable of knocking someone off their feet. Tsunami
waves can persist for many hours. As with many natural phenomena, tsunamis can range in size from
micro-tsunamis detectable only by sensitive instruments on the ocean floor to mega-tsunamis that can
affect the coastlines of entire oceans, as with the Indian Ocean tsunami of 2004.
4
Geology Content from Frameworks
Weathering & Erosion
 Weathering is the process that breaks down rock and other substances at Earth’s surface.
 Erosion is the movement of rock particles by water and wind.
 Deposition occurs where the agents (forces) of erosion lay down sediment.
 Weathering and erosion wear down, and deposition fills in the Earth’s surface.
 Although weathered rock is the basic component of soil, the composition and texture of soil and its fertility
and resistance to erosion are greatly influenced by plants and other organisms.
 Water, wind and ice are agents of erosion.
 Weathering breaks the rocks down.
 Erosion transports weathered rock material.
 Physical (or mechanical) weathering includes frost wedging, exfoliation, and thermal expansion.
 Chemical weathering includes dissolution (soluble rocks and minerals dissolve in acidic waters), hydrolysis
(feldspars alter to clay), and oxidation (rusting of iron).
 Biological weathering - organisms can assist in breaking rocks down - tree roots, lichens, burrowing
animals.
 Humans can increase erosion through poor farming practices or disturbing the land through development.
 There are practices which can be implemented to control erosion, such as contour plowing, terracing,
planting ground cover, or windbreaks.
 Waves erode the shoreline.
 Man-made structures are sometimes built to help control erosion.
 Unfortunately, man-made structures along the coastline often have the unwanted side effect of enhancing
coastal erosion.
 Construction on steep slopes can lead to mass wasting or erosion by gravity, including slumps and
landslides.
 Weathering and erosion are two very different processes that tend to act sequentially.
 Weathering is the result of the physical and chemical alteration of rock and mineral material; the resultant
products might or might not be transported.
 Erosion is the movement of rock particles by water and wind.
Human Impact
 The sun is the major source of energy for phenomena on the Earth's surface, including winds, ocean
currents, and waves.
 The Earth’s resources can be reduced or used up if humans don’t use conservation strategies.
 The atmosphere and the oceans have a limited capacity to absorb wastes and recycle mater naturally.
 Human activities, such as reducing forest cover and intensive farming have changed the Earth’s surface.
 Human activity can have a positive or a negative impact on the surface of our Earth.
 Human activities can cause or accelerate erosion.
 Human societies have long caused environmental problems whose effects persist for generations, and the
scale of these problems is rapidly increasing.
 Allowing the environment to degrade continuously can result in disasters for people that may not have an
affordable solution.
 Renewable resources can be replenished within a relatively short time period.
 Nonrenewable resources form very slowly, over millions of years. When present supplies are used, there
will be no more.
 Oil and gas are formed from the remains of marine plants, animals and microorganisms that lived in seas
millions of years ago.
5
Geology Content from Frameworks
 The ultimate source of the energy in fossil fuels is from the sun. Photosynthetic plants and marine algae
lock this energy into organic matter. When we burn plants, coal, oil, or gas, we release the sun's trapped
energy.
 When hydrocarbons are burned as fuel, they release a greenhouse gas (CO2) that is linked with global
warming.
 Burning hydrocarbons also releases pollutants such as carbon monoxide, nitrogen oxides, particulate
matter, and unburned hydrocarbons that contribute to air pollution.
 Of the total energy used in the U.S., most comes from petroleum, followed by natural gas and coal.
 Burning coal contributes to air pollution and acid rain. Burning low sulfur coal produces less acid rain.
 Certain gases in the atmosphere trap heat in the lower atmosphere (troposphere). This phenomenon has
been referred to as the greenhouse effect. Greenhouse gases include water vapor, carbon dioxide (CO2),
ozone (O3), methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons.
 Ozone protects life on earth by absorbing most incoming solar ultraviolet radiation. Release of
chlorofluorocarbons (CFC's) from aerosol cans, cooling systems and refrigerator equipment removes some
of the ozone, causing "holes"; to open up in this layer and allowing the UV radiation to reach the earth.
Ultraviolet radiation is known to cause skin cancer and has damaging effects on plants and wildlife.
 Pavement and buildings increase storm water runoff, which accelerates stream bank erosion.
 Through conservation strategies, people can slow down the degradation of the environment and the
depletion of non-renewable resources.
 Good soil conservation techniques include: contour plowing; strip planting - different crops in strips; cover
crops; crop rotation; terraces; planting groundcovers - roots hold the soil; windbreaks; tree planting;
mulching
 In general, wetlands and forests protect water quality more effectively and cheaply than human technology.
 Properly planned conservation strategies increase comfort levels and quality of life while using fewer
resources and restoring the environment.
 Many strategies for conserving resources save money as they protect the environment.

forests, or fishing grounds can be very
difficult and costly.
Topography of the Ocean
 Underneath the ocean, the Earth has plains, mountains, and valleys, which are often larger than those on
dry land.
 The Mid-Ocean Ridge system – the Earth’s underwater mountain range – arises where the plates are
moving apart. As the plates part, the seafloor cracks. Cold seawater seeps down into these cracks, becomes
super-heated by magma, and then bursts back out into the ocean, forming hydrothermal vents.
 A hydrothermal vent is a geyser on the seafloor. It continuously spews super-hot, mineral-rich water that
helps support a diverse community of organisms. Although most of the deep sea is sparsely populated, vent
sites abound with a fascinating variety of life. Tubeworms and huge clams are the most distinctive
inhabitants of Pacific Ocean vent sites, while eyeless shrimp are found only at vents in the Atlantic.
 Hydrothermal vents, geysers, are generally found at least 7,000 feet (2,134 meters) below the ocean surface
in both the Atlantic and the Pacific Oceans.
Soil
 Soil is comprised of a mixture of rock particles, decomposed organic materials, minerals, and water.
6
Geology Content from Frameworks
Fossils
 The remains and evidence of plants and animals that once lived on Earth are called fossils.
 Fossils may be used to interpret earth history of plate movement, past environmental conditions, and
history of life on earth.
 Fossils are very old, but fossils are defined as the remains, imprint, or trace of a once living organism.
 Fossils, the remains of organisms preserved in sedimentary rocks, are part of the evidence scientists use to infer
changing conditions at the earth’s surface through time
 Fossil preservation depends on properties of organic matter and environment of deposition.
 Fossils are the remains of or evidence of dead organisms. Fossils may be direct evidence, such as shells, bones,
or plant fragments, or they may be indirect evidence, such as tracks, trails, or footprints.
 A fossil is considered to be an altered hard part when all the organic material has decomposed and minerals
have replaced all of the original material.
 Fossils contain a record of Earth’s history and can be used to interpret Earth’s past physical and environmental
history as well as predictions about Earth’s future.
 Some fossils can help identify potential sites of energy resources.
 “Hard parts” of the living organism are most favorable for preservation as a fossil.
 Preservation depends on burial conditions. Fossils generally occur in sedimentary rocks, but may occur in
volcanic ash and mildly deformed metamorphic rock.
 Volcano eruptions cause ash and other sediment to be deposited on Earth’s surface. Dead critters/plants fall on
that and get nicely compressed over long periods of time, and some leave good fossil remains (in any
sedimentary type soil).
 Volcano eruptions have been used to date fossils in the layer. They can study to get the time of eruption.
7