Environmental Geology Exam 1

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igneous rocks: formed by the cooling and crystallization of molten material (magma and lava)
B horizon: may be highly variable depending on mineral content
alpine glaciers: form U-shaped valleys (higher elevations)
engineering classification: unified soil classification system; based largely on textural attributes and organic content - don't care much about chemistry
clay: <0.004 mm
systems: open or closed? - interested in movement of materials or energy within, and through, a system
transform fault: plates move laterally past each other between seafloor spreading centers
erodibility: ease that soil can be removed by wind/water. silt/sands=easy to erode. >20% clay, cohesion resists erosion.
halite and limestone: are chemical sedimentary rocks. formed when chemical or biochemical processes cause solid materials to form from substances dissolved in water.
rock cycle: start with any rock type and you can get to any other type (or the same type)
permeability: ease with which water moves thru soil
water in soil: amount of water depends on porosity (percentage of voids in the soil); movement of this water is important for pollutant transport, soil stability, and water resources
rivers: form V-shaped valleys (lower elevations)
gneiss and slate: are foliated. the mineral grains have a preferential parallel alignment.
sedimentary rocks: sandstone, halite, fossiliferous limestone
solutions: if permafrost is thin, can thaw it and then build; sink foundation into perm frozen sections; insulate to avoid melting permafrost
mountain glacier or alpine or valley: if confined to a mountain valley (mt. rainier has 25 different alpine glaciers)
denser oceanic crust: sinks below continental crust in subduction zones at convergent boundaries
concept 3: the "systems" approach
parts of earth's system: atmosphere (air), hydrosphere (water), biosphere (life), lithosphere (soil, rock)
sediment: is our greatest pollutant by volume; infills waterways/reservoirs, carries toxins
divergent plate boundary: plates diverge at mid-ocean ridges
rain shadow: precipitation shadow, is a dry region of land that is leeward of a mountain range or other geographic feature, with respect to prevailing wind direction. The mountains block the passage of rain-producing weather systems, casting a "shadow" of dryness behind them
glacier: land-bound mass of moving ice
mineral resources: are also dependent on the rock cycle. rock cycle concentrates and disperses minerals.
excavation: remove contaminated soil and treat it ex-situ
erosion: displacement of earth's materials
C horizon: weathered parent material
sand: 0.074 to 2 mm in diameter
expansive soils: soils that tend to increase or decrease (usually platey with clays....kitty litter - invented in 1947; also clay used for health reasons) (responsible for $3 billion in damages annually)
granite and basalt: igneous rocks *contain silicate minerals*
NORTH CAROLINA: infant mortality rate - 8.5/1000 live births (8.1/1000 in 2006) - minority rate is double that of white infants - NC ranks 45th (2005) in infant mortality/US minority rate - 14/1000 white = 5.9/1000/34th in smoking rate (22.8% of NC population)/US ranks 29th in infant mortality
concept 2 of the fundamental concepts of environmental science: sustainability is a goal (so our resources continue to provide benefits for humans and other living things)
hog island, va and mason inlet: are examples of surficial processes effects
gneiss, slate, and marble: metamorphic rocks
part of cape cod: is a terminal moraine and is surrounded by outwash deposits
bioremediation: use microbes to clean the soil in-situ
world's population: approximately 6.5 billion people, so population will increase by approximately 6.2 billion x .0124 this year (220,822 people/day added)
asthenosphere: hot, plastically flowing, relatively low strength
human life: will not end if growth rate reaches 0/growth rate is decreasing because of education (women), literacy, and famine, HIV, floods, etc.
small input and large output: pool or stock is reduced (use of fossil fuels)
risk: likelihood x consequences
applications of environmental geology: natural hazards (floods, landslides, e-quakes, volcanoes), land-use planning (is a particular location suitable for a proposed purpose, like a park, hi-rise, or house?), resource development (minerals like salt, gold, aluminum; soil; forests; etc.), hydrologic processes (water resources and water quality issues), geologic processes (e.g., coatal erosion), waste disposal issues
tectonic cycle: is a cycle because it results in the large scale creation, transport, destruction and recreation of earth materials.
soil pollution: contaminants "stick" to soils, e.g., metals contamination at Superfund sites. can be transported during erosion (typically due to wind or water) (hudson bay and warren landfill)
gravel, cobble, or boulder: anything bigger than 2 mm (about the size of a pea)
concept 4: limited resources (earth is our only habitat and has limited resources; recycling is necessary)
soil taxonomy: *classification system* systematic classification of soils emphasizing physical and chemical properties
silt: 0.004 to 0.74 mm
average residence time: size of stock/transfer rate through the system (average residence time = the time, on average, that a water molecule remains in the pond)
concept 6: hazardous earth processes (natural hazards must be avoided and their threat minimized)
environmental geology: is applied geology
a system: is defined as any part of the universe that we select for study
humans: make decisions that affect environment (depend on science and goals, personality, attitudes)
3 main categories of rocks: can be subdivided into additional categories
Peds: are classified by shape
plate tectonics: processes associated with the origin, movement, and destruction of these plates
corrosion: slow weathering or chemical decomposition (sinkholes)
soil profile: distinct layers of soil parallel to surface
water table: level below which soil is saturated. above this, soil contains air, water, and soilds (soil is unsaturated)
large input and small output: pool or stock grows (pollution of a lake with heavy metals)
till: glacial deposit where sediments deposited directly from the ice (clay to boulder-sized)
surficial processes: in addition to tectonic processes, the landforms we see are shaped by these. (processes that occur at the earth's surface) (including: wind, water, and ice)
silicates: minerals containing Si and O and these are the most abundant minerals
each soil layer: is called a zone or horizon
fertility: the capacity of the soils to supply nutrients needed for plant growth - varies depending on parent material
halite: has a cubic crystalline structure
marble: is nonfoliated. no preferential alignment. made from metamorphisized limestone.
plate movement: is caused by convection. as material is heated, it expands and becomes less dense so it rises.
the principle of environmental unity: everything affects everything else (rain shadow)
molten rock: often rises to the earth's surface at plate boundaries. these boundaries are 'divergent' seafloor spreading occurs at these 'oceanic spreading ridges'
convergent plate boundary: ocean-continent; oceanic plate sinks beneath continental plate;
environmental geology: is highly interdisciplinary
the 4 components of earth's system: are not completely independent
oceanic crust: is denser and generally thinner than Continental
B horizon: zone of accumulation - contains material translocated downward from overlying horizons - several types
12 orders: based on gross morphology (# and type of horizons), nutrients, organic content, color, and climatic considerations
soil properties: will have an influence on what the best use of a land parcel is
soil taxonomy: useful for agricultural and related land-use purposes and is criticised for being too complex and lacking sufficient engineering information for site evaluation
biogeochemical cycle: describes the cycling of an element through the atmosphere, lithosphere, hydrosphere, and biosphere
the geologic cycle: is really 4 subcycles: tectonic cycle, rock cycle, hydrologic cycle, bigeochemical cycles
wind transport mechanisms: similar to water
only about 0.03%: of the water on the earth is in surface water, groundwater, and the atmosphere. 97% is in oceans.
sixfold heirarchy composed of: orders, suborders, great groups, subgroups, families, and series
outwash: glacial deposit where sediments carried away from glaciers by meltwater (sand, silt, clay, gravel)
sandstone: is detrital sedimentary rock. formed from broken pieces of previously existing rocks.
element: a substance that can't be changed into another by normal chemical methods. water is not an element, but ice is a mineral and amber is not. minerals that are elements - sulfur, gold (19 times denser than water)
input/output analysis: an open system may have both inputs and outputs of a given resource. I/O analysis tells us how the stock of a resource changes within an open system.
land use: sediment loading depends on this
ease of excavation: procedures and equipment needed to remove soils
rock: an aggregate of one or more minerals
rock cycle: linked to tectonic cylce, worldwide rock recycling process driven by the earth's internal heat which melts rocks that are subducted in the tectonic cycle
key terms of tectonic cycle: core, mantle, lithosphere, asthenosphere
population growth: number one environmental problem according to Keller
B*k horizon: may be white or reddish if iron oxides are present
biogeochemical cycles: carbon, nitrogen, phosphorous, sulfur
texture: distribution of sizes of individual particles
creep (traction): movement of coarse sand and pebbles by sliding and rolling
geologic cycle: the processes that produce the materials - land, water, and atmosphere - necessary for our survival
feedback: is a system response in which output of the system (something happening) is an input (back into the system)
erosivity depends on several factors: wind speed (as velocity increases, erosivity increases); surface cover (vegetation helps hold soil in place and also slows or deflects wind near the soil surface); grain size (larger grains can cause more abrasion, but resist erosion better b/c of size)
sedimentary rocks: formed by the lithification of sediments
clay: very small grains, cohesive (sticky when wet)
surficial processes: responsible for transport and deposition. can also modify or create landforms.
earth: is often thought of as a system, basically a big machine in which parts interact
San Andreas Fault: (transform) sometimes the plates move smoothly, sometimes not towards equator. LA and SF could be neighbors in 20 million years.
color: upper layers tend to be darker because of organics
soil survey: maps showing vertical and horizontal extents of different soil types, soil description, and engineering properties. want to be able to identify potential problems before construction
india: collided with Asia approximately 50 million years ago, creating the Himalayas
continuous permafrost: the only ice-free ground is below lakes or rivers
risk: depends not only on the likelihood of an event, but also on the potential consequences of that event
dune shapes: barchan, transverse, parabolic, longitudinal
negative feedback: outcome decreases the process; it is essentially self-moderating. system may approach a steady state. (sell an item, get bad feedback, buyers won't buy from you)
Hubbard Glacier: in May 1986, it surged forward blocking the outlet of Russel Fiord, creating Russel Lake, which filled with runoff all summer and decreased in salinity, causing threats to sea life, eventually the dam gave way and the fiord was reconnected to the ocean
color: may indicate level of drainage, well-drained soils are well aerated and may have red hues (oxidized iron...think of rust)
soil particles: often cling together in aggregates called Peds
dirt: dead (sterile); sometimes try to turn this into soil.
continental glacier or ice sheet: if glacier covers large tract of land (greenland and antartica covered by these)
desertification: conversion of land from some productive state to that more resembling a desert
there is evidence: that the most recent episodes of continental movement started approximately 200 million years ago as the supercontinent Pangaea broke up
hardpan: hard (compacted or cemented) soil horizon. some people refer to a clay layer that is found around here as this. these layers are nearly impermeable and can restrict downward flow of water.
plates: move at average speed of a few cm/year (~ same as fingernail growth rate)
input and output equal: no change in size of stock (managed system such as university with constant enrollment)
glaciers: move slowly (<1 m/d) not usually thought of as hazardous to man (Hubbard glacier)
99%: of earth's carbon is in marine sediments and sedimentary rocks. burning fossil fuels, produces carbon dioxide, leading to global warming, greenhouse effect.
water content: how much water is in a soil
budget: inputs - outputs: = change in storage
urbanization: sediment loading increases with this; soil scraped off and lost, reduces strength of remaining soil; replace original soil with another and change equilibrium; draining and pumping can dry soil and change properties; increase in pollution due to chemicals associated with soils
the tectonic cycle: refers to large scale geologic processes that deform the earth's crust/the word "tectonic" has roots in latin and greek language and is related to "builder"/these large scale processes are driven by forces deep within the earth.
E horizon: may be almost white b/c it has been leached
several egyptian countries: encourage reproduction for workers, natives, pensions
feedback in natural systems: positive: erosion: off road vehicles kill plants, inducing erosion. erosion kills more plants, get more erosion, etc. (doesn't have to cause environmentally positive results)
B*k horizon: light-colored, rich in CaCO3, can form caliche; depth depends on precipitation and evaporation
plates: don't just stay in one place, they move! as they move, they may carry continents *continental drift*
problems can occurs: when water melts (subsidence) or freezes (frost heave)
e.c. coarse-grained soils: >50% of particles are larger than 0.074m, i.e., >50% sand
E horizon *Eluviation* Zone of Leaching: darker region has been leached of CaCO3. CaCO3 is deposited in white region.
divergent plate boundary: usually oceanic; spreading; the two plates move away from one another and molten rock rises up to fill the gap; mid ocean ridge forms and new material is added to each plate; African and North American Plate Boundary; Mid-Atlantic Ridge
ice on antartica: constitutes 90% of earth's ice and can be 1 mile thick! this is 70% of earth's freshwater.
San Juaquin Valley, CA: 12 cm rain/yr; poor drainage, ORV, overgrazing, wind, becoming saline, soil and groundwater, impedes vegetation growth
discontinuous permafrost: there are scattered islands of thawed ground in predominantly frozen areas
aeolian processes: can be an important factor on landform development in arid dry areas, as well as in areas with fine sediments and little protective surface cover (beaches, plowed fields, floodplains, burnt areas)
weathering: physical or chemical breakdown
if number of alpine glaicers merge: a piedmont glacier may be formed
sand: can see grains/gritty like sugar or salt
soils: solid earth material that has been altered by physical, chemical, and organic processes such that it can support rooted plant life, or solid earth material that can be removed without blasting
minerals: that we extract from the earth are used and dispersed. rock cycle concentrates them again. (may occur very slowly) (ex: phosphate, salt)
residence time in groundwater: 150 years
soil surveys and land use planning: this information can help decide whether land is most suitable for housing, light industry, roads, agriculture, forestry, septic tank systems
theory: hypothesis that has withstood sufficient testing (absolute proof is not possible; i.e., can never become fact)
the scientific method: 1)make and observation (identify problem of interest) 2)develop a question based on observation (? should be relevant and testable) 3)investigator suggests an answer to question - this is the hypothesis. good hypothesis is testable by designing an experiment that involves data collection, organization, and analysis 4)following analysis, a conclusion may be drawn. compare conclusion with hypothesis and either reject or tentatively accept the hypothesis
lithification: conversion of sediment to solid rock
windblown deposits: fall into 2 groups, based on sediment size: sand deposits (dunes) *world's biggest sand dune "Big Daddy" in Africa (1100')*, loess (windblown silt, which is smaller than sand) *the great wall of china built on and with loess and iowa has loess hills (world's highest loess deposits except china) 200'*
growth rate/doubling time: ~70/growth rate (70/1.24 = 56 years)
B horizon: clay, iron oxides, etc. leached from above
limestone: underlies coastal plain and looks strong but dissolves easily (sinkholes); main sinkhole areas in NC - brunswick, pender, new hanover, onslow, jones, lenoir, craven, beaufort
rocks: are made of one or more minerals (or other solid material like glass or organics)
soil characteristics are a function of: climate, topography, time, parent material, and organic processes (900 billion microbes/lb of soil)
convergent plate boundary: plates converge, producing a subduction zone, mountains, volcanoes, and earthquakes
many of the landforms: that we are familiar with are the result of slow acting geologic processes. these landforms developed as material was created, modified, or destroyed by physical, chemical, and biological processes.
sieves: are used to assess texture in lab
feedback in natural systems: negative: glacial retreat: an example of negative feedback would be mountain glacier retreat, eliminating low-elevation (warmer) area, thus reducing the rate of retreat
residence time: can calculate the average of materials within different compartments of the earth systems
saltation: particles briefly suspended
A horizon: organics/minerals
basalt: is an extruisive igneous rock. it cooled at or near the surface of the earth it is "fine-grained." and is a primary component of oceanic crust and is denser than granite
heat: drives convection in the tectonic cycle
loess: consists of sediments that are finer than sand (primarily silt). derived from glacial outwash which was subsequently blown away and redeposited. found near major midwestern river in N.Amer.
crust: outer part of the lithosphere
erosion: varies as a function of soil type, land use, topography, climate, and watershed size (?). measure directly or indirectly reservoir. (smaller watersheds are steeper so more erosion/larger are more gradual so less erosion)
the earth: is approximately 4.6 Ga (Giga-anna) (4,600,000,000 years old) (appalachians are 480 million years old)
loess: generally thickest downwind of the river valleys - primary loess-unaltered - secondary loess-weathered and/or transported a short distance by water
asthenosphere: is thought to be essentially continuous, while the soild lithosphere is made up of plates
metamorphic rocks: rocks formed by the altering of other rocks by heat and pressure
unsaturated: pores have water and air in them
sediment loading: how much sediment is being transferred
silt: see with 10x hand lens, flour, mix sand and silt and sand settles out
e.c. organic soils: high organic content and identified by black or gray color and, frequently, hydrogen sulfide odor
e.c. fine-grained soils: >50% of particles are smaller than 0.074mm i.e., >50% silts and clays
common soil horizons: O horizon (entirely plant litter and other organics); A horizon (organics and mineral matter)
suspension: particles <0.2mm; can travel 1000's m upward and 1000's km forward (dust storms)
feedback: think of it as the way that different components of the system interact with each other. can be positive or negative.
glaciers: produce a variety of erosional and depositional landforms
wind as an agent of geomorphic change: cloud of saharan desert dust blowing from northwest africa a thousand miles or more out over the atlantic ocean
structure: how particles are grouped together
population growth: exponential growth
residence times are used for: hog farms, wastewater spills, groundwater contamination, chlorine in water distribution system
concept 8 of the fundamental concepts of environmental science: our obligation to the future (future generations have the right to the same opportunities as us)
different rocks: have different strengths. foliation planes are potential sources of weakness. *analogous to stack of paper*
number of people added to the population each year: not constant and the increase is a percentage of the population.
soil organisms: then modify weathered rock into residual soil (modified in place) or transported soil (transported by wind or water before modification).
permafrost: thickness in alaska varies from 400 m in the north to <0.3m in southern regions and 85% of AK is underlain by permafrost (permanent or discontinuous)
sand, silt, and clay-sized particles: comprise soils
soil compressibility: measure of tendency to consolidate (decrease in volume) (coarse=low tendency, fine=high) e.g. leaning tower of Pisa
permafrost: permanently frozen ground is common in the higher latitudes
plate boundaries: are geologically active. earthquakes and volcanoes commonly occur along Tectonic boundaries.
soil classification: soil taxonomy versus engineering classification
living in cold regions: presents some unique challenges (difficult to build on organic material deposited by glaciers)
types of peds: granular, blocky, prismatic, and platy forms
causes of desertification: overgrazing, deforestation, adverse soil erosion, poor drainage of irrigated land, overuse of water supplies
environmental geology: the use of geologic information to help us solve conflicts in land use, to minimize environmental degradation, and to maximize the beneficial results of using our natural and modified environments
soil: functioning ecosystem that can sustain plant life and cylces nutrients
soil textural triangle: describes relative proportions of the different particle sizes (sand, silt, clay)
soil strength: ability of a soil to resist deformation; is a function of cohesion (ability of soil particles to stick together) and friction (most significant in coarse-grained soils)
shrink-swell potential: tendency of soil to gain or lose water
lithosphere: stronger, more rigid than deeper mantle
potential problems due to population growth: limited resources, waste disposal problems, larger populations in hazardous areas
mineral: a element or chemical compound that is normally crystalline and has formed as a result of geologic (natural) processes (also: solid, inorganic)
weathering: physical and chemical breakdown of rocks; first step in soil development
quartz: has a hexagonal crystalline structure
3 types of aeolian sediment transport: suspension; saltation; creep (traction)
world population doubled: between 1830-1930 and again between 1930 and ~1975
saturated: pores are full of water
granite: is an intrusive igneous rock. it cooled well below the surface of the earth. it is "coarse-grained." and comprises much of the continental crust
dunes: have a basic morphology (shape) they have a windward *stoss* side and a leeward side (downwind side). sand on the windward side is blown up the dune and falls down the leeward side (dune migration)
growth rate in 2001: ~1.24% per year
poorly drained soils: are wet and have low oxygen (reduced iron); producing yellow hues

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