Geology 101 Test 2: WVU Renton

Competence

A drainage patter that follows a well-developed rectangular fracture pattern in the bedrock

Oxbow Lake

A stream separated from the mains stream by levees and flowing in a nearly parallel direction

100-Year Flood

A flood with a water level that has a one percent chance of occurring in any given year

50-Year Flood

A flood with a water level that has a two percent chance of occurring in any given year

Debris Flow

A flow containing debris and most often occurring after heavy rains on barren slopes

Solifluction

A flow that occurs under sod and over frozen layers of a slope

Driving Force

A force that acts on the material in a slope to move materials in a slope to move downhill, specifically gravity

Oxidation

A chemical reaction in which oxygen combines with a cation, changing the identity of a mineral

Mechanical Weathering

A physical weathering process in which rocks break down into smaller and smaller particles

Discordant

Cutting across existing rock layers

Pothole

Deep, circular depression worn into rock by an eddy or whirlpool of a turbulent stream

What are laminar and turbulent flow, and how do they affect depositon?

Laminar-parallel: less energy and larger particles settle out Turbulent-change directions vertically and horizontally: more energy and can pcik up and transport larger particals

What is a stable vs. an unstable slope?

Stable: resisting factors exceed the force of gravity, making it unlikely to fail Unstable: resisting factors are almost the same as the force of gravity, making it likely the slope will fail when trigger occurs

How do tabular plutons differ from massive plutons?

Tabular plutons are flat whereas massive plutons have an irregular shape.

Erosion

The process in which wind, water, or glaciers removes weather particles from the environment

Pressure Release

The process that creates sheeting, occurring when erosion removes material around rocks that crystallized under pressure

Spheroidal Weathering

The process that produces rounded rocks and boulders as a result of the increased weathering of edges and corners

Undercutting

The removal of the lower portion of a slope by erosion or construction, eliminating support for the upper portion of a slope

Friction

The resistance that occurs when one object moves over another

Parent Material

The rock and minerals fragments and particles from which soil develops

Country Rock

The rock into which an igneous intrusion is injected

A Horizon

The second layer of a typical soil profile; contains humus and is part of the topsoil; also called the zone of leaching because of the transport of minerals dissolved in this layer

Traction

The size of the largest particles a stream or river can carry

What is the slowest type of mass wasting?

The slowest type of mass wasting is a creep, whose movement is not perceptible and is evident only in its effect on plants, poles, and other objects.

Channel Texture

The smoothness or roughness of the stream channel

Head

The source of the stream

Velocity

The speed of a volume of water passing a fixed poin

Weather

The state of the atmosphere with respect to various conditions, such as temperature, wind, clouds, moisture, and air pressure

Reach

The straight section of a meandering stream between bends

Dendritic Stream Pattern

The stream pattern that resembles the veins of a leaf

Load

The substances carried by a stream

Melting/Freezing Point

The temperature at which a solid melts or a liquid solidifies under a specific pressure, generally atmospheric pressure at sea level.

Inertia

The tendency of an object to stay at rest or of an object that is moving to continue to move, unless and outside force is applied

Cohesion

The tendency of particles of substance to stick together as a result of intermolecular forces

E Horizon

The third layer in a typical soil profile; also called the zone of leaching because water carries particles and dissolved minerals away from this layer

O Horizon

The top layer of a soil profile; contains an accumulation of plant and other organic material in the process of decomposing

Capacity

The total load a stream or river can carry

Eluviation

The transport of fine mineral particles to lower soil horizons

Delta

The triangle-shaped region at the mouth of some rivers, formed by deposition of silts and clays.

Differential Weathering

The weathering process in which less resistant minerals wear away first, leaving more resistant minerals behind

Sheeting

The weathering process in which sheets of granite separate from the main body as a result of pressure release

Meander

The winding turns of a river as it flows down a valley

How are phenocrysts and groundmass related to each other?

Phenocrysts are the large crystals in a porphyritic rock whereas groundmass is the aphanitic rock that surrounds the phenocrysts.

Pyroclastic

Refers to materials, such as rock, glass, ash, and scoria, that are ejected during violent volcanic eruptions.

Tabular

A flat plutonic body

Massive

An irregularly shaped plutonic body

Viscosity

Resistance to flow

What are the two largest reservoirs of water available tous?

1. Atmosphere 2. Groundwater

Describe the six main times of drainage patterns

1. dendritic-stems of leaf 2. trellis-parallel valleys located between parallel folds;flow down slopes on both sides of divide 3. rectanular-underlying rock has rectangular fracture pattern of joints or faults and follows fractures 4. radial- domal uplifting, run off as spokes 5.annular-ring 6.reversed radial-down to center sinkhole

What are the three types of load a stream carries in its total load, and how does a stream's load vary as it flows from its head to its mouth?

1.bed load 2. dissolved load: increase toward mouth of stream 3. suspended load: more variety at head downstream larger particles settle

Turbulent Flow

A chaotic flow of water in which particles move in various directions, creating eddies

Hydrolysis

A chemical reaction in which hydrogen ions, usually from water, replace the cations in a mineral structure

Soil Profile

A cross section of soil exposing soil horizons

Volcanic Neck

A cylindrical plutonic body formed when lava solidifies within a volcano's vent

Ocean Basin

A depression in the lithosphere filled with ocean water

Bowen's Reaction Series

A description of the order in which various minerals crystallize based on melting/freezing points.

Slump

A downslope movement of earth materials that rotate to form a curved surface, curved scarp, and stepped appearance

Flow

A downward movement of material mixed with water to form a mud or slurry

Reversed Radial Stream Pattern

A drainage patter resembling the spokes of a wheel in which the streams drain into the center of the pattern

Parallel Drainage Pattern

A drainage pattern in which the draining streams run parallel to one another, equally spaced apart

Braided Stream Pattern

A drainage pattern in which the stream breaks into intertwining smaller streams

Trellis Steam Pattern

A drainage pattern resembling a trellis typical of regions with long ridges and valleys

Rectangular Stream Pattern

A drainage pattern that follows a well-developed rectangular fracture pattern in the bedrock

Annular Stream pattern

A drainage pattern that runs around the bottom of a dome like a ring

Radial Stream Pattern

A drainage pattern typical of a dome area and resembling the spokes of a wheel

Resisting Factor

A factor that impedes the movement of the materials in a slope from moving downhill

Rockfall

A fall containing a rock or rocks falling as individual units

Obsidian

A felsic rock that has a glassy texture as a result of very quick cooling.

Dike

A flat igneous intrusion that cuts across existing rock layers; a tabular, discordant feature

Sill

A flat igneous intrusion that extends parallel to existing rock layers; a tabular, concordant feature

Earthflow

A flow of loose materials and water underneath a layer of sod

Mudflow

A flow of mud, usually down a stream valley

Xenolith

A fragment of country rock that has been broken off and fallen into magma, which solidified around it.

Fall

A free-falling, vertical or near-vertical downward movement of slope materials

Exfoliation Dome

A granite dome formed through the process of sheeting

What is the classification of a lahar, and how does it form?

A lahar is considered a type of mudflow. It occurs when the ash from a volcano mixes with meltwater from a glacier capping and erupting volcano, and rushes down the volcano's stream valleys

What is the difference between a landslide and slump?

A landslide moves along a plane, whereas the materials in a slump rotate, resulting in a curved path and curved scarp

Ocean

A large body of saline water that fills an ocean basin

Clay Minerals

A loose collection of minerals with a mica-like sheet structure produced by the chemical weathering of feldspars and/or amphiboles

Pedocal

A major soil type found in dry climates containing large amounts of calcium

Pedalfer

A major soil type found in wet climates and containing large amounts of aluminum and iron

Batholith

A massive plutonic feature whose exposed surface exceeds 100 square kilometers (40 square miles)

Stock

A massive plutonic feature whose exposed surface is less than 100 square kilometers (40 square miles)

Abrasion

A mechanical weathering process in which particles colliding with rocks breaks loose other particles

Weathering

A physical weathering process by which exposed rocks break down into smaller particles or into their chemicals components

Komatiite

A rare aphanitic ultramafic rock; the fine-grained equivalent of perodotite.

Laterite

A reddish clayey material that forms the A horizon of tropical soils and that hardens in the sun; often used as building material of aluminum and iron

Plutonic Body

A rock body formed by the crystallization of magma below the earth's surface; an igneous intrusion, also called a pluton

Unstable Slope

A slope that is likely to fail in the foreseeable future

Stable Slope

A slope that is not likely to fail in the foreseeable future

Laminar Flow

A smooth flow of water in which all particles are moving in the same direction

Soil Taxonomy

A soil classification system developed by the U.S. Department of Agriculture

Soil Horizon

A soil layer

Immature Soil

A soil that does not have a well-developed soil profile, because of lack of time or supportive environmental conditions

Aridisol

A soil type found in arid regions and characterized by the lack of development of soil horizons

Oxisol

A soil type found in tropical regions and characterized by thin O and A horizons, and virtually no B horizon

Tributary

A stream and river that flows into a larger river

Yazoo River

A stream separated from the main stream by levees and flowing in a nearly parallel direction

Lubricant

A substance introduced between two moving surfaces to reduce friction and cohesion

Debris Slide

A sudden downslope movement consisting of unconsolidated debris

Rock Slide

A sudden downslope movement of rock

Flash Flood

A sudden local flood, often caused by heavy rain

Laccolith

A tabular plutonic feature that inflates to a lens shape, flat on the bottom and curved on the top

What is a role of a trigger?

A trigger is something that tips the balance between the driving force, gravity, and resisting factors to set slope movement in motion

Avalanche

A type of fall in which snow, rocks, or debris tumble down a face, picking up speed and more material as the material moves downward

Creep

A very slow type of downward earth movement caused by successive wet/dry or freeze/thaw cycles

Laminar Layer

A very thin layer of laminar flow where water makes contact with the stream channel

Scoria

A vesicular rock, also known as cinder

Cinder

A vesicular rock, also known as scoria.

Retaining Wall

A wall built to support an unstable slope

Mature Soil

A well-developed soil containing significant amounts of organic matter

Talus

An accumulation of rock debris that rests against the face of a slope

Levee

An accumulation of sand-sized particles deposited along a stream channel

How is an avalanche different from a landslide?

An avalanche is a type of fall in which the materials are snow, rock, and debris. As a fall, the materials in the avalanche move in a vertical or near vertical path. A landslide involves materials that move along a plane at an angle that is less than vertical

Cylindrical

An elongated plutonic body

Hydrosphere

An envelope of water that surrounds the earth and does not include water contained in rocks, the biosphere, or the atmosphere

Flood

An even in which increased discharge of a stream or river causes it to overflow its banks

Trigger

An event that upsets the balance between gravity and resisting factors, causing the slope to fall

Pumice

An ultralight, felsic vesicular rock

Peridotite

An ultramafic rock thought to compose a large proportion of the mantle

Zone of Accumulation

Another name for the B horizon in which dissolved minerals and eluviated particles accumulate

Zone of Leaching

Another name for the horizon where leaching begins, dissolving minerals and transporting them downward to the B horizon

Deadmen

Any of a number of devices, typically buried in the ground, that extend from the backside of a retaining wall to act as anchors

Why do more basaltic magmas make it to Earth's surface than felsic magmas?

Basaltic magmas contain mafic minerals that are less viscous when melted; that is, they have less resistance to flow. Thus, they can make the journey to Earth's surface relatively rapidly, before they cool enough to crystallize. Felsic magmas contain silica, which is more viscous when melted; thus these rocks have a higher resistance to flow. The increased viscosity impedes their journey to Earth's surface, and they often cool enough to crystallize before they get there.

What is partial melting?

Because rocks are made of minerals that melt at different temperatures, a rock will melt only partially if the temperature is between the melting point of two of its minerals. The mineral that melts at the lover temperature will melt whereas the mineral with the higher melting temperature will stay solid.

How does a dike differ from a sill?

Both are tabular plutonic bodies, but a dike is discordant and cuts across rock layers whereas a stock has less than 100 square kilometers exposed.

Trace Elements

Chemical elements that naturally occur in minute concentrations, usually less than 0.1 percent of the rock or soil

Hummocky

Composed of mounds or knolls

What type of magma forms at convergent boundaries?

Convergent boundaries tend to produce cooler, more viscous felsic magmas.

What are four signs that a mass-wasting even may be likely in the near future?

Cracks in roads, concrete walls, and foundation; a hummocky ground surface; other evidence of past mass-wasting events; tilted trees or poles; and undercutting are all indications that a mass-wasting even may occur in the foreseeable future.

Name the factors that affect a streams energy

Discharge is the measurement of a stream's energy. 1. Volume-width and depth 2. Velocity-gradient and texture

Dissolved Load

Dissolved salts and minerals carried by a stream or river

What type of magma forms at divergent boundaries?

Divergent boundaries produce hot, fluid basaltic magma.

Solar Energy

Energy released by the sun as heat and light

Headward Erosion

Erosion that wears away land toward the head of a stream

Name the three main resisting factors to the pull of gravity.

Friction, cohesion and the strength of materials

How is granite related to rhyolite and gabbro related to basalt?

Granite and rhyolite are both felsic rocks but have different textures. Granite is phaneritic and rhyolite is aphanitic. Likewise, gabbro and basalt are mineral equivalents with different textures: gabbro is phaneritic and basalt is aphanitic.

Describe the movement of water in the hydrologic cycle

How water moves between land and ocean. Evaporation to water vapor; condenses and precipitation falls. If it falls on the ocean, cycle is complete. If on land, water begins to flow back to the ocean. On the way could evaporate or be released by plants.

How can a change in pressure trigger melting in rocks?

If a rock is under pressure, its melting point is increased and so it remains a solid at a higher temperature than it would at sea level pressure. If the pressure drops, the melting point decreases, and the already hot rock may start to melt.

Pegmatitic Texture

Igneous rock texture that contains crystals exceeding one centimeter in diameter

Ultramafic Rocks

Igneous rocks composed almost entirely of mafic minerals with very few felsic minerals

Intermediate Rocks

Igneous rocks containing a balance of mafic and felsic minerals

In what order do mafic and felsic materials melt?

In general, mafic minerals tend to melt at higher temperatures than felsic minerals. There is plenty of overlap, however.

What is a slope stability map?

It is a map produced by the U.S. Geological Service that describes the likelihood of a mass-wasting event in the areas covered by the map

Concordant

Lying parallel to existing rock layers

Why are magmas different?

Magmas contain different combinations of minerals and melt under different conditions. Partial melting causes the composition of magma to vary, depending upon the conditions under which the rock is melting

How are mass wasting features classified?

Mass wasting features are usually named after the type of material in motion, the angle and speed of the movement, and the amount of water present.

What is mass wasting?

Mass wasting is the downward movement of the material composing a slope

Decompression Melting

Melting that is triggered by a drop in surrounding pressure

Fluvial

Of or found in a stream, such as a fluvial deposit

Granite

One example of a phaneritic rock with felsic composition; the course-grained equivalent to rhyolite

Diorite

One example of a phaneritic rock with inermediate composition; the coarse-grained equivalent of andesite.

Gabbro

One example of a phaneritic rock with mafic composition; the coarse-grained equivalent of basalt.

Andesite

One example of an aphanitic rock with intermediate composition; the fine grained equivalent of diorite

Basalt

One example of an aphanitic rock with mafic composition, the fine-grained equivalent of gabbro

Rhyolite

One example of an aphanitic rock with mafic composition, the fine-grained equivalent to granite

Suspended Load

Particles (usually clays and silts) that are thoroughly mixed with-but are not dissolved in- the water of a stream or river

What are plutons?

Plutons are bodies of rock that have solidified underground.

Plutonic Rock

Rock that solidifies inside the earth; also called intrusive

Volcanic Rock

Rock that solidifies on the surface of the earth and is produced by or pertains to volcanoes; also called extrusive

Why do rocks have a range of melting/freezing rather than a single melting/freezing point?

Rocks are composed of minerals, each of which has its own melting/freezing point. Thus, the rock will melt over a range of temperatures rather than a single temperature.

Bed Load

Rocks, sand, and other large particles too heavy to mix with stream water

Alluvium

Sediment deposited by a stream or river

What reservoir hold most of the Earth's freshwater?

Slightly more than 74% of Earth's freshwater is frozen in glaciers

Residual Soil

Soil formed from local "in place" parent material

Transported Soil

Soil formed from parent material formed elsewhere and later deposited at the current site

Describe the distribution of water on Earth's surface

Some 97% of the water on Earth's surface is contained in the ocean. The other 3% is freshwater

Benching

Terracing of a slope to change its angle of repose

Gradient

The "dip" of a river; its rate of descent

Subsoil

The B horizon in a soil profile

Topsoil

The O and A horizons in a soil profile containing the organic material in a soil

Humus

The accumulation of decayed organic material found in the top layers of soil

Angle of Repose

The angle at which a slope is stable based on the properties of the materials composing the slope

Groundmass

The aphanitic rock around phenocrysts in a porphyritic rock

Floodplain

The area covered when a river floods, built up by sediment deposition in repeated events

Dissolution

The chemical weathering process in which minerals dissolve in a liquid, usually water

Evapotranspiration

The combined processes of evaporation and transpiration

Hydrologic Cycle

The continuous exchange of water between the ocean and land

Phaneritic

The course-grained rock texture that results from larger crystals

Mass Wasting

The downslope movement of earth materials

Downcutting

The downward erosion of the stream channel

Soil

The dynamic interface between inanimate rock and life containing regolith, humus, water, and air

Aphanitic

The fine-grained rock texture that results from crystals too small to be seen with the naked eye

B Horizon

The fourth layer in a typical soil profile; also called he zone of accumulation because eluviated particles and dissolved minerals accumulate in this horizon

Texture

The general physical appearance of a rock as observed in reflected light

Drainage Basin

The geographical area drained by a stream or river

Volume

The height times the width of a stream channel, multiplied by a one-foot or one-meter depth of the cross section

Divide

The high ground separating one drainage basin from another

Partial Melting

The incomplete melting of a rock based on the varying melting temperature of its components

Point Bar

The inside band of a curve in a river where sediment deposits

Saltation

The jumping and rolling action of rocks and sand as they are carried downstream

Phenocrysts

The large crystals cemented together by groundmass to form porphyritic rock.

Regolith

The layer of rock and mineral fragments, including soil, lying above the unweathered bedrock

Base Level

The lowest elevation at which the stream can flow; the ultimate base level is the elevation at the stream's mouth

C Horizon

The lowest layer in a typical soil profile; contains rock fragments from the bedrock below

Crystal Growth

The mechanical weathering process in which crystals that form from evaporating salt water exert pressure in cracks and pry apart rock fragments.

Frost Wedging

The mechanical weathering process in which water repeatedly enters cracks and joints, expands as it freezes, then thaws. Each cycle pries the rock apart a little more until it fails.

Why are deltas found only at a stream's mouth?

The mouth of a stream or river is where the velocity of the water slows enough for fine silts and clays to settle out and accumulate. They do so in the triangular patter characteristic of deltas

Landslide

The movement of a mass of earth materials down a diagonal slope

V-Shaped Valley

The narrow valley cut by a young stream; a canyon

Cut Bank

The outside bank of the curve in a river

How does the presence of water affect the melting point of a rock?

The presence of water lowers the melting point of rock.

Transpiration

The process by which water is released by plants

What causes the difference between a phaneritic texture and a aphanitic texture?

These textures are caused by the rate of cooling. Slow cooling allows crystals to form larger, which produces a phaneritic texture. Fast cooling causes tiny crystals and a fine, aphanitic texture.

Intrusive

Type of igneous rock that solidifies inside the earth; also called plutonic

Extrusive

Type of igneous rock that solidifies on the earth's surface; also called volcanic

Porphyritic

Type of rock composed of large crystals, called phenocrysts, that are cemented together by fine-grained rock, called groundmass

Vesicular

Type of texture that includes small air cavities called vesicles.

Freshwater

Water that lacks significant amounts of dissolved solids

Climate

Weather that is averaged over a long period of time, usually 30 years

Chemical Weathering

Weathering that occurs as a result of a chemical process

Gabions

Wire or mesh baskets filled with concrete or rock fragments and used to build retaining walls

Stoping

a processing by which magma intrudes into country rock, breaking off fragments of the country rock that then sink into the magma

What is the driving force behind all mass wasting?

gravity, which applies a downward force on slope materials

Igneous Rocks

rock that crystallizes directly from molten rock

What is meandering and what impact does it have on the surrounding landscape?

sinuous twisting and turning of a river's course. Erosion on outside bank of turn and depostion on inside. Meander migrates side to side, widening the river valley and filling it with sediment. Migrates downstream, leaving behind features such as oxbow lakes