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128 Cards in this Set

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(James Hutton, Father of Geology):
- The Earth has evolved in a constant and uniform manner
- “Present is the key to the Past” Formation of geologic features found on the Earth in the past can be explained by natural processes that occur in the present
- “Physical and Chemical Laws are constant through time
- Geologic Time is immense
Principle of Uniformitarianism
(Nicolaus Steno) Oldest bed on bottom and youngest bed on top.
Principle of superpositon
(Sir Charles Lyell) This principle states that geologic features such as faults, veins, and dikes must be younger than the rocks or features across which they cut.
Principle of Cross Cutting Relationship
(Lyell)Principle of ______(rock fragments) are always older than the host rock. Fragments within larger rock masses are older than the rock masses in which they are enclosed. Whenever two rock masses are in contact, the one containing pieces of the other will be the younger of the two.
Principle of inclusion
States that groups of fossil plants and animals occur in the geologic record in a definite chronological order.
- Original geologic time chart was based on principles of Superpositon and Faunal Succession (no understanding of the length of geologic time original)
- Divided into lengths of time.
- A valueable principle for relative dating that is based on the process of organic evolution is...
Principle of Faunal Succession
Time of no life
Precambrian
Age of ancient life
Paleozioc Era
Age of the dinosaurs
Mesozoic Era
Age of the mammals
Cenzoic Era
Discontinuity in the succession of Rock Strata
Unconformity
Nearly flat‑lying strata overlying eroded edges of inclined or tilted older strata. Produces a gap in time known as a hiatus
Angular Conformity
Beds above and below the unconformity are parallel and horizontal to one another. The beds are separated by an erosional surface creating a hiatus
Disconformity
igneous or metamorphic rocks overlain by horizontal sedimentary rock. The intrusive igneous or metamorphic rocks are older than the overlying sedimentary rocks.
Example: Grand Canyon
Nonconformity
The time in which one-half of an original amount of a radioactive atoms decays to daughter products
Half life
Atoms that spontaneously decay
Isotopes
The radioactive isotope which undergoes decay is
Parent element
The parent element undergoes radioactive decay to form a
Daughter element
Is 4.6 Billion Years Old (Lunar & Meteorite Samples)
Age of the earth due to measuring of moon rocks
Life as we may know it, began 600 million years ago (4 billion years to set the “Stage for Life”
Life began...
Accounts for 87% of Geological Time
Precambrian
78%. The Atmosphere ocean system.
- Which of the following gasses makes up the greatest percent of Earth's atmosphere
Nitrogen.
21%. The Atmosphere ocean system
Oxygen.
Weather
Troposphere
Ozone layer
Stratosphere
Greenhouse Gas - CO2
The warming of a planets atmosphere caused when certain gases (especially water vapor and carbon dioxide) absorb solar energy reflected off the surface
Greenhouse Effect
The depletion is caused by the reaction of ozone with human made chemicals such as CFC's used in air conditioners (freeone)and formally as propellants in aerosol cans.
Ozone depletion
- Freeze thaw environements. Expansion of H20
Ice Wedging; Physical weathering (mechanical)
- Expansion of rock towards free surface
- Thermal expansion
- exfoliation of upper sheets
Sheeting; Physical weathering (Mechanical)
- Rooting
- Hoofed animals
- Microscopic Organism (lichens and moss)
Animals and plants
- H20 + CO2 = H2C03
- Acid rain
Hydrolysis, Chemical weathering
- Dissoliving of rock in H20
- Limestones
- Evaporites
Melting of rocks in water
Dissolution; Chemical weathering
- Exposure of rock to 02-
- Significance of red
- Iron Ore Minerals
Oxidation, Chemical weathering
Is a result of differences in the rates of weathering
- Different rocks weather at different rates
- Granite most resistant rock
- Quartz most resistant mineral
- Shale least resistant
- Climate
Differential weathering of rocks
Topsoil of sand and clay
A horizon
Subsoil of Clay
B Horizon
Weathered bedrock
C Horizon
thick A Thin B
Grassland soil
Thin A thick B
Forest soil
Rain
Rates of weathering
- Slowdown hill movement of the upper layers of the rock or strata.
- Upper edges of the slope are bent downslope
Hillside Creep
Rapid movement of the rock and strata along a curved geometric surface
- Slump Block (Landslide California)
Slump
- Uplift if very rapid
- Eroision is much slower
Differential Eroision
- Uplifted dome
- Eroision of upper strata of dome
- Exposure of the oldest rocks in the center of the structure
- Oldest bed in the middle
Eroison of inclined strata
- Location of Countries and landforms
- Location of property
- Constitutional rights
- Right of ownership
- Court house documents
Importance of maps
- Cover large areas of land with minimal on-ground surveying
- Overlap images by 60% to provide 3-D images of the surface
Aerial Photography
- first Satellites were camera operated. Camera pod was ejected into the atmosphere for recovery
- digital satellites relay real-time information to earth stations
- Sputnik series of spy satellite images
- I-10 and Beltway 8 (HCC-NW Town and Country campus)
- Landsat images with natural color enhance false color
- Lake Powell, Death Vally
- Location determination via Triangulation
Landsat and Radar Imagery (Remote sensing by Satellites)
- North-South Lines
- Prime meridian
- 0 degress longitude
- Greenwich England
Location coordinates; Longitude
East- West Lines
- Equator
- 0 degress latitude
Location coordinates; Latitude
- Longitude lines are equidistant
- High latitude continents are bigger than they are
Mercator Projection
- Latitudes are equidistant
- Warps E-W latitudes
- Trends to solve aerial coverage problems
Conical projection
- Texas utilizes the Spanish Land grant System
- Haphazard survey method using boundaries of rivers, Natural landforms, and Oak trees
- Inherited from Spain to Mexico to the Republic of Texas to the USA
Public land survey system
- USGS mandated by the Executive branch to keep and maintain all official maps fo the USA
United States Geological Survey USGS Topographic maps
Show the configuation of the Earth's surface by means of Countour lines
- Coutour lines are of equal elevation
Topographic maps
Verbal scale 1":1 mile
- Graphical scale (if map is reduced or enlarges by copying the graphical scale will also be proportionately reduced or enlarged)
Scales
Constant difference in elevation
Contour interval
Highest point - lowest point
- Countours "v" upstream
- Closed contours indicate hills
- Closely spaced contours indicate a steep slope
Relief
Subsurface water contained within pore space (voids) of a rock.
- Due to the infiltration of water
Groundwater
Study of Groundwater
Hydrogeology
The amount of void space within a rock (%), good porosity~30% lends itself to water storage.
- Example: Sandstone, shale
Porosity
Capacity or ability of a rock to transmit fluid (darceys), good perm example: Sandstone not Shale (impermeable)
- The ability of a porous solid to transmit a fluid is called
Permeability
Pore space is < 100% saturated
Zone of Aeration
Pore space is 100% saturated
Zone of saturation
The upper surface of the Zone of Saturation expressed as an elevation (not constant)
Water table
Water is transmitted from high pressure to low pressure due to elevation differences in the Zone of Saturation.
- Outcrops of the water table represent low pressure which may occur at Springs, Rivers, and Lakes
Hydraulic Head
Hydraulic head is great enough to cause the water to rise above the top of the acquifer when it is tapped by a well.
Example: Edward's Aquifier, Barton Creek, Austin
Artisean Aquifer
Balcones Fault Zone and Edward's Aquifier
US Major Aquifiers
Inversion of the water table due to the mining of groundwater.
- Allows air to enter bore hole causing foaming at the surface
Cone of Depression
Leached fluids from illegal disposal pits.
- Case I: Leached into sandstone
Case II: Leached into shale
Groundwater pollution
Infiltration of saltwater in coastal aquifiers due to groundwater mining
Saltwater Encroachment
Extraction of water from the zone of Saturation causing the collapse of pore space and ultimetley the ground itself.
- Subsidence in Brownwood, Texas
Subsidence
- Hot rocks
- Fractured reservoir
- Ample supply of groundwater
- Yellowstone national park
Thermal Geysers and Springs
Based on Radiometric decay of ______
Isotopes
So by measuring the amount of Parent to Daughter isotope in an ______ one can calculate the age of the rock
EX:
After one half life
- 50% Parent
- 50% Daughter
Time: 100 my

After two half lives
- 25% Parent
- 75% Daughter
Time: 200

After three half lives
- 12.5% Parent
- 87.5% Daughter
Time: 300 my

After four half lives
- 6.25% Parent
- 93.75 Daughter
Time: 400 my
Igneous Rock
Soil Formation
Regolith
24 satellites at a cost of 12 billion dollars (4 on stand by)
Global Positioning System
90% Runoff
Urbanization
90% infiltration
Rural
Increases infiltration in Urbanized areas
Detention Ponds
Network of Tributaries that grow by Headward Erosion.
- Dendritic erosional pattern
Collection System
Transition from gullies to intermittent streams to permanant tributaries
Headward Eroision
- Meandering main channel that funnels water to the Delta
- Formation of Point bars and Cutbanks
- Decrease in tributaries downstream
Transporting System
Stream velocity is measured in...
ft/sec
Speed at which different sized sediment settle in a water column measured in ft/sec
Settling velocity
Amount of water and sediment a stream can carry. Large streams have a high capacity (large cross-section)
Stream Capacity
Size of the largest particle a stream can carry. Small streams have a high competence (high flood velocity)
Stream Competence
Amount of water passing a given point during a specific interval of time
Discharge
= ft.2 * ft/sec = ft.3/sec
(x section * velocity = discharge.
Discharge ft3/sec (volume over time)
Coarse load of gravel and boulders.
- Settling velocity > Stream Velocity.
- Gravel moves by Saltation, boulders by rolling
Bedload
Fine particles of silt and clay.
- Stream Velocity > Settling velocity
Suspended Load
Settling velocity is > than Stream Velocity
Point bar deposition
Stream velocity is > than settling Velocity
Cutbank Eroision and transportation
- Due to broad plateau uplifts and down cutting of stream
- Function of secondary uplifts of a mature river system
- Differential eroision and weathering
Entrenched (Incised) Meanders
- System of dividing distributaries
- Site of massive depostion of stream load
Dispersing system
- River reaches base level (lowest level to which a stream can erode)
- Stream gradiant approaches zero
- Stream velocity decreases
- Settling velocity > Stream velocity
- Deposition of load as mouth bars at sea level
- Stream divides into distributaries
Dispersing System Dynamics
- Depostion of 7 lobes through time
- Lobe 7 formed by US Corps of Engineers for navigation purposes
- Delta wants to capture the Atchafalya basin
- Lobe 7 depostion
- Fine particles of silt and clay (green areas) are carried farther from the source area
Mississippi River Delta History
Ice sheets that cover large portions of a continent
Continental Glaciers
Ice streams confined to valley or canyons
Valley Glaciers
River (fluvial) Valleys are...
"V" shaped
Glacial valleys are...
"U" shaped due to the over steepened valley walls
Lifting of boulders from the sides and floor of the glacier due to ice wedging
- Glacial Horns
Glacial Plucking
- Ice age started 2 million years ago
- 4 periods of glaciation
- Biological impact; Homo sapiens and mammels
Pleistocene Glaciation
- Wobble of earth's axis
- Decrease on CO2
Causes of Ice Age
- Eroision and collapse of limestones cavers by hydrolysis causing sinkholes H20 + CO2 = H2CO3 (carbonic acid)
- Sinkhole formation Florida
Series of sinkholes occurs in Florida, Kentucky & Tennessee
Karst Topography
Where does saltwater encroachment occur?
Coastline
- Based on Radiometric decay of Isotopes (atoms that spontaneously decay)
Absolute Time (Quantitative)
- Ex: U238 to Pb 206 Uranium to lead
- Atomic number decreases due to decay of the nucleus
Decay from Parent to Daughter product
Other World Delta's include...
- Mekong, Vietanm
- Niger, Nigeria
- Nile, Egypt
Relative (Qualitative)
dating is determining the...
Chronological order of a sequence of events
Is characteristic of a continent's stable platform and forms plateau's, mesas, buttes, and pinnacles
Differential eroision of Horizontal Strata
Historical significance of angular unconformity. Sequence of events are...
Depostion of lower beds horizontially as they were here because of superpostion, eroision
- Depositon of A or older strata
- Tilting of A
- Erosion of A
- Depostion of upper beds
History of Disconfonformity
- Depostion of A, lower bed
- Erosion of lower bed
- Depostion of upper bed
forms disconformity
What is the atmosphere composed of?
Nitrogen & Oxygen
Physical weathering includes...
- Ice Wedgeding
- Sheeting
- Animals & Plants
Chemical weathering includes...
- Hydrolisis
- Dissolution
- Oxidation
How long does it take to build a mountain?
A million years, not very long
Is the #1 agent even in desert of eroision
Water
The order of eroision of Horizontal Strata
- Plateau
- Mesa's
- Butte
- Pinnacle
Formation of arches are formed by...
Water
Transition from gullies...
Carries water when it rains
Intermittent streams...
Wet season
Permanent tributaries...
All year around, erodes upslope
Stream velocity is measured in...
Ft/sec
What is depostion of stream?
- Conglomerate
- Sandstone
- Siltstone
- Shale
Lowest level to which a stream can erode..
Base Level
The daugher product eventually formed by the decay of uranium is...
Lead
Which type of rock is best for age dating...
Igneous
- Inner banks contained by levee deposits
- Outer banks contained by bedrocks
- Meanders with Point Bar and Cutbank Environments
- Oxbow lakes from cutoff meanders
Transporting stream dynamics
Which of the following rocks is known to have a low permability?
Shale