Ch3: Earth Materials

Match the type of natural cement with its description.

Calcite - CaCO3; holds grains moderately well but is easily dissolved. Silica - SiO2; forms a strong cement that can tightly bind grains. Clay minerals - May cement together larger grains, such as sand; may form through alteration of feldspar or volcanic ash. Iron oxides - Hematite is one example; commonly gives sediment in a reddish color.

Match the weathering process with type and best example.

Dissolution - Soluble minerals break apart in a weak acid; chemical weathering Oxidation - Rust forms on some minerals containing iron; chemical weathering Biological activity - Roots grow into rock fractures and pry the rock apart; physical weathering. Thermal expansion - Rocks crack after heating up in a wildfire; physical weathering

Sedimentary rocks are formed by the compaction and cementation of sediments in a process called ________.

lithification

The mechanical breaking apart of rocks that are exposed to the environment is called _________ weathering.

physical

Thermal expansion, biological activity, near-surfacing, and frost and mineral wedging are all examples of ___________ weathering.

physical

Match the depositional environment with the sediment most likely to be found there.

Steep mountain fronts - Large, angular rocks Dunes - Sand-sized grains Stream channels - well-rounded sand and larger pebbles and cobbles

Texture in igneous rocks may refer to which of the following? (Select all that apply.)

- Variation of crystal size in the rock. - Overall crystal size - Presence of holes and rock fragments.

Which of the following are ways rocks may form? (Choose all that apply.)

- When magma cools and solidifies - Under high pressures and temperatures deep within the Earth - Precipitation from hot waters - Through the consolidation of loose sediment

Most of the material contained within nonclastic sedimentary rocks consists of ________ (Choose all that apply).

- minerals precipitated from solution as water evaporates. - materials formed through biological activity such as making shells or other hard parts.

In this image of a porphyritic igneous rock, the finer grained material is called __________, while the larger crystals in this material are called ________.

matrix; phenocrysts

The process in which a rock may move from one place to another or be converted into a new type of rock type is the ____ cycle.

rock

The general term for Earth materials that are consolidation is _____.

rocks

Which of the following would be representative of the present is in the key to the past"? (Select all that apply.)

- Observing a volcanic eruption and the solidification of lava to infer how some types of igneous rocks were formed millions of years ago. - Inferring that the sediment type in a modern environment would have been in the same in a prehistoric version of that environment. - Using a modern example of the processes of rock formation to determine past processes of rock formation.

Which of the following are possible products of chemical weathering? (Select all that apply.)

- Oxide minerals - Ions in solution - Soil - Clay minerals

Match the nonclastic sedimentary rock with its description.

Chert - Silica-rich rock; may form from accumulation of remains of microscopic planktonic organisms. Iron formation - Layers of Fe-rich layers intermixed with fine-grained quartz; may be mined for use in steel. Coal - Formed the burial, compaction and heating of wood and other plant parts; may be lignite, bituminous, or anthracite.

________ metamorphism occurs when rocks are heated locally and have little associated deformation, whereas _______ metamorphism involves heating and deformation over large areas.

Contact; regional

Determine the compositional content of the igneous rocks by placing them in the correct category.

Felsic - Granite,Rhyolite Mafic - Basalt, Gabbro Intermediate - Andesite, Diorite

________ is molten rock on Earth's surface.

Lava

Match the igneous rock texture with the location where it likely formed.

Pegmatite - A: deep within Earth in the presence of water. Porphyritic - A and B: first deep within Earth and then later near the surface. Vesicular - B: near Earth's surface, as gas bubbles through the lava.

Geoscientists organize igneous rocks according to what 2 main properties?

Size of crystals and kinds of minerals.

What feature of igneous rocks refers to the overall crystal size, variation of crystal size, and the presence of other features, such as holes and rock fragments?

Texture

Which of the following best describes physical weathering?

The mechanical breaking apart of rocks that are exposed to the environment.

Rock and mineral pieces called _________ make up the type of sedimentary rocks called __________ rocks.

clasts; clastic

Deposition may be caused by both _________ and _________.

decreases in transportation energy; precipitation of ions from water.

Lava is a molten rock that cools _______.

on the surface

Which of the following are ways in which various factors influence the type of sediment transported? (Select all that apply.)

- A steep slope is more likely to have large, angular, and poorly sorted clasts than a slope that is gentle. - Transported sediment must be available as part of the sediment supply in the area. - A stronger current may transport larger clasts than slow-moving currents. - Wind only carries small particles, while ice and swift-moving water may carry large clasts.

Nonclastic sedimentary rocks may form in which of the following ways? (Select all that apply.)

- Accumulation of remains of organisms - Evaporation of water

Which of the following processes have occurred to create the rock in the image? (Select all that apply.)

- Deformation - Metamorphism

What are some methods by which sediment is delivered into the oceans? (Select all that apply.)

- Flowing water from rivers. - Blowing wind. - Falling/settling sediment due to its gravity.

Which of the following are shown in the image? (Select all that apply.)

- Lava - Volcanic ash

Which of the following correctly describe the locations identified on the image? (Select all that apply.)

- Location B represents a pyroclastic flow of thick clouds of volcanic ash, gas, and rock fragments, which may become welded after deposition. - Location A represents volcanic ash, which may fall to Earth and become nonwelded.

Compaction causes sediment to become _________. (Select all that apply.)

- More dense. - More compact.

Sediment may form when dissolved material is extracted from water in which of the following ways? (Select all that apply.)

- Precipitated through biologic activity of aquatic life (e.g., corals) - Precipitated by chemicals reactions.

The factors that can cause metamorphism of other existing rocks include ________. (Choose all that apply.)

- Pressure - Temperature - Deformation

Which two of the following processes might magma undergo as it cools? (Select all that apply.)

- Solidification - Crystallization

What processes occur when a rock is buried deeply enough and heated enough that the rock is folded and altered in a solid state?

Deformation and metamorphism

Which of the following correctly describes the terms detritus and detrital?

Detritus is loosened and transported clastic material; detrital describes deposits of detritus.

Which of the following best describes chemical weathering?

Reactions that affect a rock by breaking down minerals, forming new minerals, or removing soluble material.

Which of the following are the four main components of Earth's landscapes? (Choose all that apply.)

Sediment, soil, solid bedrock, and vegetation.

The pore spaces that remain after the sediment compaction are often filled when dissolved materials _______ out of a solution. These minerals (materials) act as a natural ________ that binds clasts together.

precipitate; cement

Match the image with its best descriptions.

A - Rock contains small holes called vesicles. - Rock is vesicular. B - Volcanic ash and pumice has been compacted while still hot to solid rock. - Rock has a welded texture. C - Angular fragments of volcanic rock are present within a finer matrix. - Rock is a volcanic breccla.

Match the type of igneous rock on the left with its description on the right.

Felsic - Abundant quartz and feldspar, light colored. Mafic - Contains pyroxene, calcium-rich plagioclase feldspar; dark-colored. Intermediate - Abundant plagioclase feldspar and amphibole; biotite or pyroxene; gray or black and white may be common colors. Ultramafic - Contains more magnesium and iron-rich minerals, such as olivine; dark to green colored.

Choose the answer that best explains why a rock might not go through the complete rock cycle.

Rock may only move through part of the cycle or be involved in a variety or processes in different sequences.

Which of the following are ways in which deposition may occur? (Select all that apply.)

- A clam creates a shell by removing ions out of the water it inhabits. - Water in a stream slows down and can no longer transport the larger sediment, which then settles out in the stream channel. - Ions in solution in the water of a lake are precipitated out to create solid sediment that accumulates at the bottom of the lake.

Which of the following correctly describe the terms 'clast' and 'clastic'? (Select all that apply.)

- A clast is a piece of rock, such as a pebble, that may combine with other clasts to make a clastic sedimentary rock. - A clastic rock is a sedimentary rock that contains clasts.

Identify the factors that strongly influence the size, shape, and/or sorting of sedimentary clasts that are transported. (Choose all that apply.)

- Steepness of slope - Strength of current - Agents of transport - Sedimentary supply

Place the following events in the most logical order of what could happen to a rock exposed at the surface. Place the first event on the top.

1. Rock is newly exposed at the surface through uplift. 2. Physical and chemical processes act on the rock to cause weathering. 3. Broken apart pieces of rock are stripped away from their original source through erosion. 4. Glaciers, flowing water, wind, or gravity transport sediment across the landscape. 5. A decrease in energy no longer allows sediment to be moved through its environment and it undergoes deposition.

Match the correct descriptions to each image comparing phaneritic and aphanitic igneous rocks.

A - This is a phaneritic-textured igneous rock. - Crystals in the rock are visible to the unaided eye. B - Crystals are not visible to the unaided eye. - This is an aphanitic-textured igneous rock.

Match the location with its expected description.

A - Clasts are large, angular, and poorly sorted. B - Clasts have begun to loose their sharp edges and have started to become broken into smaller pieces. C - Clasts have become well-rounded pebbles and sand. D - Only the smallest clasts are found here; sediments are much better sorted as a result.

Match the sedimentary rock name with the description that is the best fit.

Conglomerate - Rounded pebbles and cobbles with sand and finer particles between the larger clasts. Breccla - Angular pebbles and cobbles with sand and finer particles between the larger clasts. Sandstone - Sand-sized particles; rock may have some defined layer. Shale - Very fine-grained clay minerals; rock may break into sheetlike pieces due to mineral alignment.

Match the coarse-grained igneous rocks on the left with their fine-grained compositional equivalents on the right.

Granite - Rhyolite Diorite - Andesite Gabbro - Basalt Peridotite - Hardened ultramafic lava

Match the weathering process with type and best friend.

Near-surface fracturing - A rock breaks away from a steep cliff; physical weathering. Frost and mineral weathering - Crystals of ice (or crystals and salt) grow and expand in thin fractures of rock; physical weathering. Hydrolysis - Clay minerals form from silicate minerals exposed to somewhat acidic water; chemical weathering. Biological reactions - Bacteria consume parts of some rocks; chemical weathering.

Match the types of foliation with its image and description.

Schistosity - A; Parallel orientation of mica and other platy minerals. Flattened pebbles - C; Deformed objects, like in this metamorphosed conglomerate. Gneissic - B; Alternating light- and dark- colored bands of different types of minerals. Ductile shearing - D; Flattened and smeared out minerals grains.

Match the four main components of natural landscapes with their descriptions.

Sediment - Loose pieces of various sizes (boulders to mud) formed on or near Earth's surface; pieces are carried and deposited in various environments. Soil - Near-surface material in which we grow crops; formed from the breakdown of materials more or less in place. Bedrock - Rocky materials solidly attached to the Earth and its subsurface. Vegetation - Various types of plant life that grow on Earth's surface.

Match the rock type with the process by which it might form.

Sedimentary - Loose sediment on Earth's surface is deposited by moving water, air, or ice, and then is buried and consolidated. Igneous - A volcano erupts lava, which then cools and solidifies. Metamorphic - Previously existing rocks are changed by temperature, pressure, or deformation deep within Earth. Hydrothermal - Rocks precipitate directly from hot water beneath Earth's surface.

What is the best description of pore spaces in rock?

Spaces that exist between the grains that make up the rock.

Match the terms to their best descriptions.

Volcanic ash - This erupts vertically from the volcano; it cools significantly in the air before landing back on the surface. - After deposition, the material is likely unwelded. Pyroclastic flow - Under the influence of gravity, this moves rapidly down the side of a volcano; the material is still generally very hot when it is deposited. - After deposition, the material is most likely welded to some extent.

Match the volcanic feature with its correct description.

Volcanic ash - Volcanic material that is erupted into the atmosphere and falls back to the Earth to blanket the terrain. Lava - Molten rock that flows out onto Earth's surface. Magma chamber - An area molten rock that may cool and solidify below the surface of Earth and form such rocks as granite. Magma - Any molten rock that is still beneath Earth's surface.

Match the igneous rock type with its best formation description on the right.

Volcanic glass - Forms when magma erupts on the surface and cools quickly with no crystal formation. Fine-grained igneous rock - Forms when magma only has enough time to grow small crystals. Coarse-grained igneous rock - Forms when magma has a slow cooling rate, which results in large crystals. Vesicle - Forms when gases dissolved in magma accumulate as bubbles.

Match the processes of the rock cycle with their definitions.

Weathering - Breaking down of rocks either mechanically or chemically. Transportation - Moving pieces of rock by wind, ice, or water. Deposition - Occurs when the energy of the transported materials decreases. Uplift - Upward movement of underground rocks to the surface. Lithification - Process of sediment turning into rock.

Hydrolysis, biological reactions, dissolution, oxidation are all processes associated with ___________ weathering.

chemical

The rock shown here, with sediment just visible to the naked eye, is a ________.

sandstone

When rocks are broken down and worn away, they form loose materials of all sized called _______.

sediment

The four main parts of a landscape include _________, _________, ________, and _______. (Use just one word for each blank.)

sediment, soil, rock, vegetation