FANR 3060: Chapter 1 Study Guide
62 Cards in this Set
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Geology
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Describes the composition and structure of the earth, especially land masses, and explain how it got that way.
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Physical Geology
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Includes:
the study of minerals and rocks
geomorphology
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Minerals
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naturally occurring compounds with distinctive physical properties
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Rocks
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assemblages of minerals
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Geomorphology
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Study of landscape features and formation
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Historical Geology
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Pieces together the history of the earth, from physical and biological clues (fossils), including the origin of modern landscapes
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Igneous Rock
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One of the three basic classes of rock
Form in the molten mantle of the earth from magma, which either cools slowly beneath the surface (intrusive/plutonic) or rapidly when ejected from a volcano or surface magma flow (extrusive/volcanic)
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Intrusive (Plutonic) Rocks
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Type of igneous rocks that have large visible mineral crystals
Examples: Granite, Diorite, Gabbro (see "Rocks" flashcards)
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Extrusive (Volcanic) Rocks
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Type of igneous rocks that have much finer mineral grains than intrusive rocks due to rapid cooling
Examples: Rhyolite, Andesite, Basalt (see "Rocks" flashcards)
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Metamorphic Rock
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One of the three basic classes of rock
Result of re-melting of igneous or sedimentary rock, commonly caused by tectonic events (plate collisions) that crush and heat rocks under pressure
Examples: Slate, Quartzite, Marble, Schist, Gneiss, Amphibolite (see "Rocks" flashcards)
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Sedimentary Rock
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One of the basic classes of rock
Particulates that have accumulated in thick beds, usually in water, then consolidated into rock either through pressure, cementation, or both
Examples: Shale (Mudstone), Sandstone, Conglomerate, Limestone, Dolomite, Coal (see "Rocks" flashcards)
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Primary Minerals
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Crystallized from molten magma as it cools after moving away from the earth's core
some are unstable when exposed at the earth's surface and weather rapidly into secondary minerals
Igneous rocks are composed solely of primary minerals
Examples: Quatrz, Feldspar, Ferromagnesian, Mica (s…
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Evaporite Minerals
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Form from evaporation or chemical precipitation from seawater; typically soluble, not stable in soil environments.
Examples: Calcite, Gypsum, Rock salt (see "Rocks" flashcards)
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Secondary Minerals
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Form as weathering products from the decomposition of primary minerals
Metamorphic and sedimentary rocks are composed of a mixture of primary and secondary rocks
Examples: Kaolinite, Vermiculite, Iron oxides (see "Rocks" flashcards)
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Rock Cycle
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A) Igneous rocks formed in the molten interior of the earth are thrown up by various geologic forces into mountain ranges or highlands
B) These rocks weather into soil material, which then erodes by runoff, ultimately to be deposited in the ocean as thick layers of sedimentsC) These sedi…
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Tectonic Activity/ Forces
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Uplifting of land masses to form mountains/ plate collisions
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Erosional
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Being worn down
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Depositional
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Built up by the action of water flowing over and through the landscape
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Earth's Core
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Dense, molten mixture of iron and nickel at very high temperatures
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Earth's Mantle
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Semi-molten, plastic zone that slowly circulates due to convection currents originating in the core
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Earth's Crust
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Solid upper part of mantle; divided into plates composed of denser, high iron rocks that less dense rocks, continents, float on)
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Continental Drift
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Localized heating in mantle causes liquid pockets that move closer to the crust and cools, then moves closer to the core and melts --> this causes the crust to move
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Mountains
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Form when two continent bearing plates collide head-on smashing and squeezing rocks between them
Often these rocks are metamorphosed in the process
Sometimes molten magma is squeezed up from the lower mantle to form new igneous rocks
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Physiography
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Types of landforms that exist on the earth's surface
(See "Geologic History of Georgia" flashcards to see how the current physiography of Georgia formed)
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Landscape
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Unit of land area, characterized by distinctive and/or uniform topography and having more-or-less typical geology and geologic history, soil types, and hydrologic conditions
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Relief/ Topography
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Describes the shape of the surface of the landscapes (whether steep or flat or something in between), and the soils and hydrology that may occur there of the landscape
1. High relief= steep (more streams with steeper gradient)
2. Moderate relief= rolling (greatest soil thickness and d…
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Formations of landscapes
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Both steeper and level landscapes (younger land forms) weather and erode over long geologic time periods to form rolling landscapes (oldest and most stable land forms)
Steep landscapes(tectonic/mountainous) are eroded down
Level landscapes are nearly always depositional, adding new mate…
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Infiltration
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Rain soaks into ground
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Runoff
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Rain does not soak into ground
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Climate
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Rainfall amount, distribution, and temperature
Plays a large role in creating landscapes
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Alluvium
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Eroded, soil-like material laid down on the floodplains of major rivers (depositional)
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Karst
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Landscapes formed on limestone and has caves because limestone dissolved
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Muck
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a peaty soil material formed from plant debris that accumulate in the low areas where the water table comes right to the surface
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Saprolite
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Porous soil-like material (weathered rock)
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Aeolin
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Wind blown
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Soil Profile
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A vertical section through a soil with depth, down to the rock layer below;
A vertical section through a soil with depth down to the rock layer below; made up of layers of soil (horizons) with varying properties such as texture, color, and structure.
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Soil Texture
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Refers to particle size of the soil (how coarse vs fine)
Clay= <0.002mm in diameter
Silt= 0.002-0.05mm in diameter
Sand= 0.05-2mm in diameter
Textural classes are named mixtures of sand, silt, and clay
Loam: mix of sand and silt
GA: A horizons= sandy, B horizons= clayey, C horizons=…
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Soil Color
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Gives you clues about soil composition
Topsoils= brown or black (due to organic matter or humus)
Subsoils= bright colors (red, yellows due to oxidized iron/ has oxygen) or grey (due to reduced iron/ no oxygen, indicating wet/ saturated soils)
B horizons have more iron than A horizons b…
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Soil Structure
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Refers to how the sand, silt, and clay particles are held together into aggregates or peds
In A horizon, humus binds soil into rounded, porous granular aggregates
Subsoils have angular, more dense blocky aggregates.
Structure in the B horizon is created by movement of clay and Fe in th…
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O Horizon
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layer of decomposing leaf litter on the soil surface (not found in tilled soils)
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A Horizon
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Topsoil, usually colored brown or black by humus
Often low in clay-->sandy or silty texture
major root zone for plants and the cultivated layer in agriculture
distinctive structure of granular
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E Horizon
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Leached out (light-colored), low-clay horizon found under A horizon
Low in humus and iron, which rainwater has leached to B horizon
If there is an E horizon, there must be a B horizon
Often absent from GA soils
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B Horizon
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Accumulation of material that has been leached out of the A and E horizons
Higher in clay and iron
Colored red or yellow (in well-drained soil) or grey (in poorly drained soils)
Distinctive structure of blocky due to higher clay content
Does not need an E horizon to have a B horizon
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C Horizon
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Weathered parent material from which the soil formed
Lower in clay and iron than the B horizon
Contains rock fragment and weathered rock structures in upland sites
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R Horizon
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Hard bedrock
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Soil Series
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Certain sequence of horizons with certain properties defining a certain type of soil
Given names based off the town where the soil was first described
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Soil
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Mantle of weathered rock that covers the earth's land surface
Medium for plant growth
Affected by specific soil-forming processes (weathering, leaching, humus additions)--> these properties create distinctive soil properties form horizons
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pH of Rain Water
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pH= 5.5
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Hydrologic Cycle
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Water moves though landscapes in a series of processes and there is a balance between inputs of water (precipitation) and outputs (Evaporation and transpiration)
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Formula of Hydrologic Cycle
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Formula: P=Q+ET+(change in S)
P=precipitation
E=evaporation (to the atmosphere)
T= transpiration (to the atmosphere)
Q= discharge (of water in soil)
S= storage (of water in soil)
Change in S= change in storage, which is an increase or decrease over time
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Watershed
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Land area within the boundaries of which all water drains to a single outlet point
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Water Table
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Saturated zone in the subsoil
Springs may occur where a water table outcrops to the surface
Note: water the percolates into the soil and below may continue to flow (leak) through the bedrock to some deeper water table below, or may follow a flow path different from the surface watershed…
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Stream Order
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Defines the size of the stream based on how many other streams intersect it, counting only perennial streams
A first has no perennial tributaries, a second order is made up of intersecting first order, etc. (largest rivers= seventh or eighth order, moderate rivers= four or five order)
S…
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Dendritic Pattern
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Streams intersect at acute angles and form a random branch-like network over the landscapes
Most common (and most common in Piedmont)
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Rectangular Pattern
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Ridges often direct major streams through valleys with smaller streams running up hill slopes
Often determined by geology
Common in the Valley and Ridge province of GA
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Trellis Pattern
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Develops in loose erodible soils where major streams quickly cut down into the landscape and feeder streams branch out laterally
Common in some parts of the Coastal Plains of GA
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Where does mountain-building energy come from?
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The heat at the core of the earth, originally derived from the gravitational energy and radioactivity decay
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Where does mountain eroding energy come from?
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The erosive power of rainfall
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Where does the impact energy of raindrops and erosive power of flowing water come from?
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From the sun, which evaporates water from the surface into the atmosphere, from which it falls back to earth as rainfall
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What wears down the mountains and powers the erosive part of the rock cycle?
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Hydrologic cycle
How it works:
The photons of light from the sun hit a water surface, and are absorbed by some of the water molecules, which raises them to a higher energy level- and as they become more energetic, they have the baility to escape the liquid phase and enter the gas phase.…
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Where does all the energy that reaches earth's surface go?
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60-70% is used to evaporate water, 2% used for photosynthesis, the rest is lost to the atmosphere
Formula: Rn= L*Et+P+H+G
Rn=net incoming solar radiation
L= heat of vaporization of water
Et= evapotranspiration rate
H= heat loss to atmosphere
G= heat transfer downward in soil
P= ene…
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Stone Mountain
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formed from melted rock (magma/igneous rock) injected under ground from the heat of the collisions with Africa 350 million years ago
This pluton of magma cooled slowly to become a dense, hard, coarse-grained crystalline granite
Slowly over geologic time the surrounding rocks (which we…
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FANR 3060: ROCKS