ASBOG Questions Flashcards

Aquifer
Terms Definitions
List USCS gravel classifications
GW-well graded, GP-poorly graded, GM-silty, GC-clayey
List the USCS sand classifications.
SW-well sorted, SP-poorly sorted, SM-silty, SC-Clayey
How are clastic rocks classified
Size; sorting and distribution; or chemical content of silica, feldspar, and calcite
how many grain sizes does a poorly-sorted sample contain
a wide range
A well-sorted sediment or sedimentary rock contains how many grain sizes?
only 2 or 3
What factors may influence the efficiency of a well
Borehole size, soil conditions, gravel packing, casing characteristics, and screening characteristics
Describe the general factors affecting specific yield.
As the grain size increases, this also increases. Some materials are made of charged ions that adhere better to water and also has an affect on this.
List the Dupuit assumptions in groundwater investigations.
For unconfined, consistent flow above a solid boundary: the direction of groundwater flow is horizontal; hydraulic gradient is the same as the water table slope; and equipotential lines are vertical.
How are magmatic segregation deposits formed?
By differentiation or direct cyrstallization of magmas except for deposits that have a component of hydothermal transport.
What geophysical method is used to help determine the rippability in subsurface materials?
Seismic refraction.
What act covers existing hazardous waste sites?
RCRA, 1976, as amended
The TEGD requires a minimum of how many detection monitoring wells and where should they be placed?
1 upgradient and 3 downgradient
Accoding to TEGD, what techniquies should be used for logging monitoring wells?
Log drill cuttings; collect samples by split spoon, Shelby tube, Pitcher tube, or modified California sampler; and geophysical logs.
Type of test is used to determine potential yield or specific capacity?
Bail down test.
What methods can be used to control and prevent salt water intrusion into a fresh water aquifer?
Controlled pumping, artificial recharge, injection barrier ridge, man-made subsuface barrier (such as a slurry wall), pumping wells between ocean and water supply wells.
In a distance-drawdown pumping test why are the drawdown measurements from the closest well to the pumping well used?
The test wells closest to the pumping well are the most accurate representation of conditions at the test well.
What vaule of TDS is considered saline?
>=10,000 mg/l
What is the relationship of equipotential lines to flow lines?
They are perpendicular to each other and closely resemble squares.
How do caverns from?
By dissolution of limestone along joints and bedding planes.
How is well efficiency presented?
As a ratio in percent of theoretical drawdown to actual drawdown measured in a well.
What are moraines composed of?
A heterogeneous collection of unsorted and unstratified clay, silt, sand, gravel, and boulders.
What features are characteristic of larger clasts within a moraine deposit?
They are faceted and have striations or polish due to abrasion during the movement of the glacier.
Describe the elements of a landslide investigation.
Assemble historical information on the natural and human history of the region (municipal files, notes from other geological projects, aerial photos, reports, maps) and an investigation of subsurface conditons (topography, drainage, geological structure, weathering, faults).
What are the common types of inorganic contaminants.
Arsenic, lead, mercury, cadmium, chromium, white phosphorous, selenium, nitrate, perchlorate.
What are the symptoms and origination of arsenic contamination?
Originates in nature, pesticides, herbicides, insecticides; can result in cancer and enzyme malfunction
What are the symptoms and origination of lead contamination?
Originates in nature, manufacturing, mining, and fossil fuels; can result in damage to the central nervous system and death.
What are the symptoms and origination of mercury contamination?
Originates in nature, manufacturing, mining, and volcanic activity; can result in damage to a fetus and to an adult central nervous system.
What are the symptoms and origination of cadmium contamination?
Originates in batteries, welding, and cigarette smoke; can result in lung, kidney, and digestive system damage.
What are the symptoms and origination of hexavalent chromium contamination?
Originates in manufacturing; can result in lung damage and cancer.
What are the symptoms and origination of white phosphorous contamination?
Originates in nature and manufacturing; can result in liver, heart, and kidney damage.
What are the symptoms and origination of selenium contamination?
Originates in nature and in refining of copper; can result in damage to the central nervous system.
What are the symptoms and origination of nitrate contamination?
Originates in fertilizer, manure, and sewage; can result in infant blood disorders.
What are the symptoms and origination of perchlorate contamination?
Originates in rocket fuel; can damage the function of the thyroid gland.
Discuss the features formed by lava flow and how they can help orient a bed.
Unique contours are created by differential cooling. In the lowest areas, sediment will become baked, higher up the rock will be lighter and more filled with air.
Discuss the features formed by particle deposition and how they can help orient a bed.
When wind and water carrying particles lose speed, the particles will begin to settle out by grain size. Course grains settle out first and fine grains last. Ripple marks indicate the direction of flow. The bottom of a beach formation can be suggested by basal conglomerates of coarse sandstone.
What characteristics can seismic refraction determine?
Seismic velocity, uniaxial tensile strength, weathering, abrasiveness, and spacing of discontinuities.
What term is often used analogously to effective porosity?
specific yield
How would the spontaneous potential, resistivity, and gamma ray logs respond to salt water?
low to moderate spontaneous potential, low resistivity
How would the spontaneous potential, resistivity, and gamma ray logs respond to limestone?
low spontaneous potential, high resistivity, low gamma
How would the spontaneous potential, resistivity, and gamma ray logs respond to sandstone or sand?
high spontaneous potential, moderate resistivity, low gamma
How would the spontaneous potential, resistivity, and gamma ray logs respond to shale or clay?
low spontaneous potential, low resistivity, high gamma
How would the spontaneous potential, resistivity, and gamma ray logs respond to hydrocarbons?
extremely high resistivity
How would the spontaneous potential, resistivity, and gamma ray logs respond to freshwater?
low spontaneous potential, high resitivity
what processes are included in diagenesis
compaction, cementation, reworking, authigenesis, replacement by secondary minerals, crystallization of secondary minerals, leaching, hydration, bacterial action, or formation of concretions
What causes the various grades of coal
Increasing time, burial depth, and higher temperatures
How is peat formed
when decaying vegetation does not have enough oxygen
How are evaporites formed
by evaporation of lake waters in arid regions or from marine waters in restricted basins where the rate of evaporation balances the recharge of the basin with saline water
why don't shales provide a very good indication of geologic conditions at the time of formation
they appear in many environments
how do you determine a rocks susceptibility to chemical weathering
an inverse relationship to their order in Bowens reaction series
What geologic conditions may form petroleum traps
1. deformation of reservoir rock, folding, faulting, or both; 2. stratigraphic variations in reservoir rock directly caused by the depositional environment or unconformities; 3. hydrodynamic forces, 4. a combination of the above factors, 5. diapirs
what conditions do reservoir rocks need to have to allow migration, accumulation, and storage of petroleum to occur
rocks need to be of sufficient porosity and permeability
what radiometric age-dating techniques would be used for materials that are 10 million years old
rubidium-strontium, uranium-lead, lead-lead, uranium-helium, fission track, thermoluminescence, electro-spin resonance
what age is rubidium-strontium dating used for
>10 million years
what age is uranium-lead used for
>10 million years
what age is lead-lead dating used for
>10 million years
what age is uranium-helium used for
300,000-18 million
what age is fission track used for
100,000-several billion
what age is thermoluminescence used for
few hundred to 1 billion
what age is electro-spin resonance used for
few hundred to 300 million
what can be inferred from a borehole log indicating a repetition of beds
it indicates reverse faulting
What type of geologic feature might you expect from a mapped outcrop pattern that consists of a series of concentric circular shapes
horizontal beds mapped on a rounded hilltop or an enclosed basin. Or an intrusion with bands of contact metamorphism of varying degrees
What are the different types of unconformities
angular unconformity, nonconformity, disconformity, paraconformity
What type of V will a vertical bed display on a map
A vertical bed will have no V
in which direction does an anticline plunge on an outcrop pattern
in the direction of the closure
which direction does a plunging syncline plunge with respect to closure
away from closure
what causes metamorphic changes in contact metamorphism?
principally by heat, but also by magma composition and deformation related to the intrusion. Relatively low pressure and temperatures 200-1,000C
What does a neutron log show and what is it commonly used for
curve of intensity of radiation produced when the rocks ina borehole are boombarded by neutrons. It indicates the presency, but not type, of flued. Often used with gamma ray log to distinguish porousand nonporous formations
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