Exam 1

Earth Science 101 with Rafique Ahmed at University of Wisconsin - LaCrosse

About this deck

By: Ashley McCarthy
Textbook:

Elemental Geosystems: An Introduction to Physical Geography-Textbook only
Created: 2012-02-18
Size: 92 flashcards
Views: 25

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Five Themes of Geography

1. location-answers the question of where

2. region-areas having uniform characteristics: desert, artic, tropical regions

3. Human-Earth relationships: represents interactive relationships between land and humans: how we use/abuse land

4. Place: each place is unique because of its living/nonliving characteristics

5. Movement: transportation, communication, circulation, of goods/services

What is the age of the Earth?

4.6 billion years old

Pre-Cambrian Eon

88% earths history
modern atmosphere formed
no plants, animals, fossils

Cambrian Period

first fish and fossils

Carboniferous Period

formation of coal and gas
the Appalachian mountains formed- 480 million years ago

Triassic Period

age of dinosaurs
Pangaea formed
oil and gas formed

Cretaceous Period

flowering plants
Atlantic basin started to drift-formed Atlantic ocean
Rocky-Andes mountain chain formed- 75-80 million years ago

Tertiary Period

Alpine-Himalayan mountain chained formed- 28 to52 million years ago

Quaternary Period

first humans
ice ages- 4 glacial advances and retreats

most recent Wisconsin Glaciation- 10,000 years ago

Crust

outer skin of the earth: 8-40 KM thick

Moho

the film of fluid materials lies below the earths lower crust: does not allow earthquake waves pass through

Lithosphere

extends from surface to 70 KM depth: everything above moho, solid state

Asthenosphere

layer below the lithosphere: plastic state, provides floating mechanism to lithosphere

Upper Crust

absent under oceans: contains felsic rocks (light color rocks, mainly granite)

Lower Crust

mafic rock (dark color rock, heavier, mainly basaltic rocks)

Igneous Rocks

90-95% of crust
formed from consolidation of magma in the crust

Intrusive Igneous Rocks

rocks that consolidate within the crust
the greater the depth the slower of the rate of cooling and the coarser the texture

Extrusive Igneous Rocks

consolidation occurs at surface
very fast rate of cooling, no crystals (fine crystals if any) form

Plutons

massive igneous rock formations inside crust

batholith-dome shaped; formed at base of crust, bottom extends to magma
laccolith- dome shaped, flat based
sill- horizontal formation within crust
dikes- wall like formations inside crust
volcanic plug- hardened magma pool exposed after erosion of surrounding rocks

Sedimentary Rocks

4-8% of crust
rocks formed due to deposition and consolidation of sediments in low lying areas

% Limestone,Shale,Sandstone

Limestone-10% of all sedimentary rocks
Shale-70% of all sedimentary rocks
Sandstone-15% of all sedimentary rocks

Four stages/Steps in Formation of Sedimentary Rocks

1. Sediment-deposition in low lying areas

2. compaction-due to pressure from the overlying layers

3. lithification-removal of moisture/water due continued pressure from the overlying layers

4. sedimentation- bonding of rock particles by the chemicals left behind of water

Cementing Materials of Sedimentary Rocks

Calcite-calcium carbonate
Quartz-Silicon Dioxide
Iron Oxide

Metamorphic Rocks

Rocks formed due to physical and chemical changes caused by extreme heat and pressure

Continental Shields

oldest massive igneous rock formations, from the precambrian period (1/2-3 million years old)
geologically stable
acted as nucleus of continents

Mountain Roots

remnants of the old fold mountain chains
250 to 420 million years old
erosion and weathering reduced their heights

Active Mountain Chains

mountains still growing/active

Continental Shelf

extension of the landmass into ocean with a gentle slope

Continental Slope

steep slop from edge of continental shelf

Oceanic Trench

narrow, deep, canyon-like feature located next to the continental slope

Abyssal Plain

the plain oceanic floor

Mid-Oceanic ridge

mountain chains on ocean floor

Plate Tectonics Theory

lithosphere is broken into pieces called plates which are constantly moving random directions and speeds (1-17cm/yr), due to magma convection

Features caused by Plate Tectonics Theory

Present day arrangement of continents and oceans, alpine-himalayan mountains, rocky-andes mountains, mid-oceanic ridges, East African Rift Valley, oceanic trenches, earthquake and volcanic chains

Brief History of Plate Movement (Pangea, Laurasia, Gondwana, Tethys Sea)

465 million years ago: continents upside-down, southern hemisphere
225 million years ago: Pangea

northern lobe: Laurasia
southern lobe: Gondwana
separated by Tethys Sea

Evidences of Continental Drifts or Plate Tectonics

parallel coast line across atlantic; similar rock structure on both sides of the atlantic; similarity in the fossils found in southern america, india, austrailia, and antartica; presence of coal bed in antartica; presence of midoceanic ridges

Three Types of Plate Movement

convergent-two plates move towards each other
divergent- two plates move away from each other
transform or transcurrent- plates move laterally past each other in the opposite direction, grinding past each other

Subduction (Convergent Plate Movement)

subsidence (sinking) of the thinner oceanic plate under the thicker continental plates; form volcanic arcs

Oceanic Trenches (Convergent Plate Movement)

in the area of subduction oceanic trenches form

Volcanic Chains (Convergent Plate Movement)

formed by convergent plates (in areas of subduction)

Earthquake Zones (Convergent Plate Movement)

earthquakes occur along the zones of plate convergence

Mid-oceanic rides (Divergent Plate Movement)

magma rises along the cracks on the ocean floor forming the mid-oceanic ridges

Spreading (Divergent Plate Movement)

spreading of the sea floor from mid-oceanic ridges; two plates being pushed apart

Rift Valley (Divergent Plate Movement)

The East African Rift Valley

Transform (Transcurrent) Plate movement

San Andreas Fault

Volcano

a cone shaped landform created by repeated eruptions of magma

Lava

fluid materials that flow down the slope

Tephra (Pyroclastic Debris)

volcanic ash that is thrown into the air, which returns to surface due to gravity and precipitation

Lahar

low of volcanic ash and snow-melt down the slope of a volcano

Caldera

a large, usually circular depression at summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir

Hotspots

chains of volcanic islands formed in the oceanic crust; not located along plate boundaries or volcanic chains

Folding

bending of the preexisting rock layers due to compression or plate convergence
syncline-downward bending
anticline-upward bending

Warping

3 dimensional bending of rock layers
dome-upward 3-d bending
basin-downward 3-d bending

Faulting

displacement of a set of rock layers along the crack in the crust
major cause- plate diverging/minor cause-excessive plate converging
fault plane-the plane along which displacement of rock layers occur
fault scarb- exposed part of uplifted fault
footwall- the wall which slopes at angle on which the other wall rests
hanging wall-the wall the rests on the footwall

Normal Fault

the hanging wall gets displaced downward relative to the footwall; caused by plate divergence

Reverse Fault

the hanging wall is displaced upward relative to the footwall; caused by plate convergence

Transform/transcurrent Fault

two plates move horizontally in the opposite direction, grinding past each other; caused by differential speed of fault segments

Overthrust Fault

the hanging wall rides on the footwall at a small angle; caused by excessive convergence

Block Faults

two parallel faults in which the midsection may drop (garben) or rise (horst)

Earthquake

a sudden movement or jolt in the earths crust

cause-sudden release of accumulated frictional energy

focus-a point where earthquake originates

epicenter-a point at the earths surface directly above focus

Richter scale-represents amount of frictional energy (joules) released by earthquakes (magnitude of an earthquake)

Factors that Determine the Extent of Earthquake Damage

magnitude, depth of focus, proximity to population, stability of the rocks, land use type

Earthquake Zones

located along plate boundaries

Tsunami

giant oceanic wave (circular wave) caused by a major earthquake on the oceanic floor (500 mi/hr)

Weathering

disintegration and decomposition of rocks by the agents of weather

Erosion

disintegration and decomposition by the agents of transportation (rivers, wind)

Mechanical Weathering

disintegration of rocks due to weather

Frost/Freeze Action-disintegration of rocks due to freeze thaw action(mid-latitude climate)

Salt Cracking-occurs in desserts, evaporation of groundwater leaves behind salt crystals

unloading or exfoliation-occurs in convex exposed surface, disintegration of layer by layer

thermal expansion- occurs in exposed rocks in deserts; expansion from day heat and cooling night

Biological Weathering

disintegration of rocks by growing plant roots and borrowing animals

Scree(Talus)

deposition of rock particles at base of cliff produced by frost wedging

Chemical Weathering

decay/decomposition of rocks due to presence of chemicals in the water

oxidation-rocks containing iron turns into rust, presence of moisture

carbonation-rocks containing calcite(limestone) or dolomite, falling rain+CO2 form carbonic acid disolving calcite and dolomite

Two Factors that determine Chemical Weathering

chemical weathering increases with increasing rainfall and temperature

Regolith

layer of consolidated rock debris produced by weathering (upper layer-soil, fine particles)

Soil

the upper layer of regolith consisting of fine rock particles, which is capable of supporting plant life

Out crops

exposed part of bedrock

Mass Wasting/Mass Movement

downward movement of regolith on a sloping surface caused by gravity

Six Factors of Mass Wasting

1.Slope Angle-the steeper the slope, the more likelihood of slope failure and the faster the mass weathering

2.Orientation-rock layers parallel to surface-unstable; rock layers at an angle to surface-stable

3.Weakening of Material by Weathering

4.Increased Water Content

5.Changes in Vegetation

6.Overloading

Types of Mass Wasting

Creeps-small movements of soil in over time, directed by gravity gradually downslope.

Landslide-a rapid movement of a large mass of earth and rocks down a hill

Flows-Movement of regolith that resembles fluid behavior(avalanche,mudslide)

Topples-instances when blocks of rock fall away from a slope

Slump-slipping of rock material along the curved surface of a decline

Falls- a fall (rock fall)-not huge quantity

Hydro-logic Cycle

* Describes the continuous movement of water on, above and below the surface of the Earth

* Precipitation, Evaporation, Condensation, etc...

Water Balance Equation

E = Evaporation

T = Evapotranspiration

Q = Surface water runoff

G = Ground water flow

Capillary Flow

* The ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.

* Example....moisture being sucked up by dry dirt, Sun sucking moisture from dirt, etc..

Infiltration

* The process by which water on the ground surface enters the soil.

* Governed by GRAVITY and Capillary Flow

Factors of Infiltration

Slope angle of ground surface
Hydraulic conductivity of soil (higher this value, greater infiltration)
Presence of vegetation cover
Density of vegetation cover

Groundwater

A layer of rock or regolith in which all the pore spaces are saturated with moisture

Water Table

Top of the Ground Water

Aquifer

A layer of permeable rock, saturated with moisture, sandwiched between two layers of impermeable rocks

Aeration Zone

The layer of rock or regolith between the surface and the water table

* Moist but not saturated

* During wet period water infiltrates into aeration zone

* During dry period moisture moves from aeration zone to the atmosphere

Ogallala Aquifer

* A vast yet shallow underground water table aquifer located beneath the Great Plains in the United States.

Effects of Excessive Groundwater Withdrawal

1) Cone foundation in the water table needs much deeper tube well

2) Sinkholes--Water withdrawal creates voids in the rocks or regolith, resulting in the rocks collapse forming a SINKHOLE

3) Sea Water intrusion--When voids created by water withdrawal in coastal areas is filled by seawater intrusion.

Carbonic Acid Rain and its Effects

*Formed by sulfur dioxide, nitrogen oxide, and carbon dioxide mix with moisture in the atmosphere

* Limestone is very easily dissolved by Carbonic Acid Rain

Karst Topography

Landform in a limestone country.

Rock Climate combo needed for formation of Karst Topography

* Limestone Bedrock

* Humid Climate

Surface features formed in Karst Topography

* Sinkholes-- small basins formed at the surface in a limestone bedrock

* Disappearing Streams-- stream that disappears underground in limestone country

What is a Cavern and its features

* Cavern= caves in a limestone country (Mammoth Cave, KY)

* Stalactites= From ceiling

* Stalagmites= From floor

About this deck

By: Ashley McCarthy
Textbook:

Elemental Geosystems: An Introduction to Physical Geography-Textbook only
Created: 2012-02-18
Size: 92 flashcards
Views: 25

About StudyBlue

“I have been getting MUCH better grades on all my tests for school. Flash cards, notes, and quizzes are great on here. Thanks!”
Kathy