GEO 101 EXAM 3

Hydraulic action (erosion)

squeeze and release action of flowing water that loosens and lifts rocks

Compression stress

squeezes rocks together till it folds or break

unstable slope

strength does not exceed gravity and denudation

shear stress

stress that occurs when forces act in parallel but opposite directions, pushing parts of a solid in opposite directions

Geomorphology

study of landforms

Geomagnetism

study of phenomena associated with Earth's magnetic field - shows evidence of seafloor spreading

Closer to the surface what happens

temperature and pressure decline and rocks are more rigid

ungraded stream

Has many temporary base levels. With time, the stream smoothes out the irregularities to develop a graded profile.

slide

Landslide—large amount of material failing simultaneously Translational slide—movement along a flat surface roughly parallel to the angle of the slope Rotational slides—moves along a concave surface

Theory of Plate Tectonics

Lithosphere is divided into plates that float on the asthenosphere. Boundaries create new crust, mountains, and seismic activity.

Hydrolysis (chemical weathering)

Minerals interact with water

mass movement

Movement of Surface Material Propelled Downward by Gravity

Slap pull

Near the trench, gravity pulls plate downward

Principle of Superposition

Oldest rocks are at the base of a rock formation while younger rocks are at the top of the rock formation

Earthquakes

Plates do not glide smoothly past one another. Sharp release of energy causes semsic wave

Rills and Gullies

Rill is a shallow channel in some soil, created by the erosion of flowing water. When rills get large enough that they cannot easily be removed, they're known as gullies

fall

Rockfall—simply a rock that falls Debris avalanche—mass of falling and tumbling rock, soil, and other material

Folding

Rocks are deformed as a result of compression

salt crystal growth (physical weathering)

Salt works its way up cracks, crystalizes and expands

Features of Karst Topography

Sinkhole- circular depressions, can collapse Towers- in the humid tropics, deeply jointed, thick limestone beds can be left as towers Caverns- Caves form just beneath water table

Normal faults, reverse faults, and strike-slip faults

Tension in Earth's crust pulls rock apart pushed together Horizontal movement

frost action (physical weathering)

breaks up rocks from repeated freezing and thawing of ice in cracks in rocks

Endogenic processes

brings heat energy and new material to the surface and recycles old material, moves and reshapes crust

seafloor spreading

builds mid-ocean ridges and drives continental movement

Mid ocean ridges

As they spread, more magma rises to create a new crust

drainage basin

-Collect water and sediments from drainage basins -any area of land where precipitation collects and drains off into a common outlet

Alfred Wegener

A German scientist who proposed the theroy of continental drift

Continental Divide

A drainage divide that separates drainage basins that empty into different bodies of water surrounding a continent

divergent boundary

A plate boundary where two plates move away from each other. Occurs in long rift valleys and mid ocean ridges

Transform boundary

A plate boundary where two plates move past each other in opposite directions

convergent boundary

A plate boundary where two plates move toward each other. Produce subduction zones

graded stream

A stream that has the correct channel characteristics to maintain exactly the velocity required to transport the material supplied to it.

karst topography

A type of landscape in rainy regions where there is limestone near the surface, characterized by caverns, sinkholes, and valleys. Weathering and erosion caused by groundwater can create underworld caverns.

metamorphic rock

A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions. Harder and more resistent to weathering

Which of the following was not offered as evidence to support Alfred Wegener's hypothesis of continental drift?

A)The "jigsaw puzzle" shape of the continents B)rock assemblages on opposite sides of the Atlantic Ocean C)Matching fossils of species on now separated continents D)Lack of oceanic ridges that would indicate sea floor spreading D

Interfluve

Area of high ground separating two river valleys or basins

Which of the following is true? A. The age of the sea floor is the same in most areas of the ocean. B. The age of the sea floor does not follow a discernable pattern. C. The age of the sea floor increases with increasing distance from a midocean ridge. D. The age of the sea floor increases with increasing distance from a trench.

C) The age of the sea floor increases with increasing distance from a midocean ridge.

Carbonation (chemical weathering)

Carbon dioxide reacts with certain types of rocks forming a solution that can easily be carried away by water.

Oxidation (chemical weathering)

Certain metallic elements combine with oxygen rusting

What plate boundaries can earthquakes occur at

Convergent-compresional forces, Reverse faults, Divergent- tensional forces. normal faults, Transform- shear forces, strike slip faults

Core

Dense and metallic, solid iron in the inner core, molten iron in the outer core

Mid-oceanic ridges occur at ________ plate boundaries.

Divergent

Principle of Uniformitarianism

Earth processes occurring today are similar to those that occurred in the past

Effusive eruptions

Effusive eruptions

Igneous rocks

Form directly from cooling of magma or lava. Ex: granite (magma) and obsidian (lava). Melt under high tempature and pressure

organic sedimentary rock

From shells and skeletons of marine organisms (coquina limestone) and the decayed remains of plants (coal)

continental drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

Mantle

The layer of hot, solid material between Earth's crust and core, represents 80% of Earths volume

base level

The lowest level to which running water can flow and erode

Orogensis

The process of mountain building

chemical weathering

The process that breaks down rock through chemical changes. Common near the equator and in the summer, usually in the prescence of water

aggradation

The progressive accumulation of sediment along or within a stream.

stream graident

The slope of the stream and is measured by the difference in elevation. Steeper near head, more gentle near base

Erosion

Transport of materials by shit

confluence

Two tributary streams join together

Subduction zones

When the denser oceanic crust hits lighter continental crust, it slides beneath, creaing this

Deep-ocean trenches

a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle

The maximum incline at which sediments on a slope can remain at rest before pulled downward by gravity is known as the

angle of repose

upward fold downward fold

anticline syncline

Mohorovičić (Moho) discontinuity

separates crust from the mantle

littoral zone

shallow sea zones

Tides

caused by the gravitational pull of the moon and sun

Types of volcanic activity

depends on source and viscosity (magma thickness or resistance to flow)

Four classes of mass movement

fall, slide, flow, creep

Rocks respond to stress by

folding (bending) or faulting (breaking)

sedimentary rock

form from fragments of eroded (worn away) rocks (sediments) that are put at low-lying areas (lying close to the water) and then compacted to form new rocks

intrusive igneous rock

form from mantle material injected into the crust where it cools and hardens beneath the surface. Magma dissolves into crustal rocks to form these rocks

Explosive eruptions

highly viscous and explosive

stable slope

if strength exceeds gravity and denudation

Where do earthquales beigin

in focus(hypocenter)

slopes

inclined surfaces that vary with rock structure and climate.

differential weathering

inconsistencies in rock composition, depressions, and cracks expose rock to various weathering processes. Not all rock weathers the same way.

Gravity is driving force downward. Resisting force is the strength of the slope material.

know that

lithospheric plates

large pieces of Earth's lithosphere that move over the asthenosphere

pressure-release jointing (physical weathering)

layer after layer of rock peels off in curved slabs or plates.

Contact metamorphism

magma rising to the surface "cooks" nearby rocks

As lava erupts along a mid-ocean ridge...?

magnetic particles cool and orient toward magnetic north. Creates ongoing magnetic record of Earth's polarity

chemical sedimentary rock

materials dissolve in water and harden into rock.

Weathering

physical and chemical processes that break up or dissolve rock

Hot spots

places where molten material from the mantle reaches the lithosphere

convection current

powers plate tectonics

Exogenic processes

processes Earth materials with the chemical and physical action of water, ice, and wind

Rock cycle

produces igneous, metamorphic, and sedimentary rocks

Tension stress

pulls on the crust and stretches rocks and make it thinner; occurs where two plate are moving apart

clastic sedimentary rock

rock fragments that compact under the weight of overlying layers and then cement and harden

Abrasion (erosion)

rock particles grinding and carving the streambed like sandpaper

extrusive igneous rock

rock that forms from the cooling and solidification of lava at Earth's surface, through volcanic activity. Magma extrudes as lava onto the surface to form these rocks

regional metamorphism

rocks buried inside crust subjected to high temperatures and pressures over millions of years

Faulting

rocks on either side of fracture move relative to the other side, leads to earthquakes

physical weathering

the mechanical breakdown of rocks and minerals. Dominate at high lattitudes and altitudes, common in the winter

denudation

the processes that cause the wearing away of the Earth's surface by moving water, by ice, by wind and by waves

Lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle.

creep

the slow downhill movement of weathered rock material. Freeze-thaw cycles, dry/wet cycles, daily temperature changes

Alluvium

the sorted material deposited by a stream

asthenosphere

the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.

stream discharge

the volume of water passing a point along the river in a unit of time.

low viscosity high viscosity

very fluid not fluid

flow

when moisture content is high Earthflows and mudflows

Ridge push

when the force of gravity moves a plate downward and away from a ridge

stream erosion

when water transports sediment