PHYSICAL GEOLOGY COMPREHENSIVE ANSWERS
AND QUESTIONS SET A+
✔✔Brittle v ductile depends on - ✔✔- Temperature
-Pressure
-rate of deformation
-composition of rock
✔✔Ductile deformations can result in - ✔✔1. monoclines
2. synclines (U) - core is youngest
3. anticlines (n) - core is oldest
✔✔Deformation's three stages - ✔✔1. Elastic (reversible)
2. Ductile (some permanent strain)
3. Fracture (irreversible)
✔✔Grabben - ✔✔
✔✔tectonic foliation - ✔✔the layering created by the alignment of deformed and/or
reoriented grains. Overall, deformation can produce inequant grains and can cause
them to align parallel with one another, thereby generating metamorphic foliation in the
rock.
✔✔boudinage - ✔✔process that leads to the formation of boudins from originally
continuous layers
✔✔Oil and gas are formed by - ✔✔-algae and plankton from ancient marine
environments
--> organic materials mixed with sedimentary particles.
-->O2 poor environments are necessary so the organics are not degraded by bacteria
--> as more sediments pile on, dead organics and are converted into oil and gas over
years of 'cooking' underground
--> found under lithified shale which comes from stagnant silt and and mud sediments
, ✔✔The conditions for oil and gas formation can be found in.... - ✔✔the tropics.
Abundant life
✔✔Energy from hydrocarbons come from.... - ✔✔the long chains of carbons.
--> longer chains are more viscous
✔✔only a small window of certain depths allow conditions for oil and gas formation -
✔✔kerogen (2-4 km)
oil (4-6km) [ 90 - 160 C]
Natural gas (up to 9km) [225- 250 C]
Graphite (>9km) [>250 C]
✔✔Porosity - ✔✔%age of the rock that is pore space
✔✔Permeability - ✔✔Degree to which fluids travel may through a rock
✔✔Geologic formation oil traps - ✔✔1. anticline traps
2. fault traps
3. salt dome traps
✔✔Anticline trap - ✔✔Oil pools at the top of anticline and is trapped by a seal rock
✔✔Fault trap - ✔✔Reservoir rock may be faulted up against an Impermeable rock.
✔✔Salt dome trap - ✔✔Oil/Gas found between impermeable shale and an impermeable
salt dome.
✔✔Stratigraphic trap - ✔✔changes in rock permeability, porosity due to patterns of
different sediment deposition
✔✔Fracking is used to what end in the extraction of natural gas + oil - ✔✔It allows for
increased permeability by fracturing the ground
✔✔How are tar sands formed? - ✔✔Oil reserves that are subjected to microbial
degradation become tarsands.
✔✔How is coal formed? - ✔✔Derived from ancient plant matter that has been buried,
compacted and 'cooked' to remove N, O, S, H, leaving only carbon
✔✔What are the various stages of coal? - ✔✔Lignite (70% C)-> bituminous coal (85%
C) -> Anthrasite (95% C)
✔✔If coal deposits are too hot/ too deep, we have... - ✔✔graphitization
AND QUESTIONS SET A+
✔✔Brittle v ductile depends on - ✔✔- Temperature
-Pressure
-rate of deformation
-composition of rock
✔✔Ductile deformations can result in - ✔✔1. monoclines
2. synclines (U) - core is youngest
3. anticlines (n) - core is oldest
✔✔Deformation's three stages - ✔✔1. Elastic (reversible)
2. Ductile (some permanent strain)
3. Fracture (irreversible)
✔✔Grabben - ✔✔
✔✔tectonic foliation - ✔✔the layering created by the alignment of deformed and/or
reoriented grains. Overall, deformation can produce inequant grains and can cause
them to align parallel with one another, thereby generating metamorphic foliation in the
rock.
✔✔boudinage - ✔✔process that leads to the formation of boudins from originally
continuous layers
✔✔Oil and gas are formed by - ✔✔-algae and plankton from ancient marine
environments
--> organic materials mixed with sedimentary particles.
-->O2 poor environments are necessary so the organics are not degraded by bacteria
--> as more sediments pile on, dead organics and are converted into oil and gas over
years of 'cooking' underground
--> found under lithified shale which comes from stagnant silt and and mud sediments
, ✔✔The conditions for oil and gas formation can be found in.... - ✔✔the tropics.
Abundant life
✔✔Energy from hydrocarbons come from.... - ✔✔the long chains of carbons.
--> longer chains are more viscous
✔✔only a small window of certain depths allow conditions for oil and gas formation -
✔✔kerogen (2-4 km)
oil (4-6km) [ 90 - 160 C]
Natural gas (up to 9km) [225- 250 C]
Graphite (>9km) [>250 C]
✔✔Porosity - ✔✔%age of the rock that is pore space
✔✔Permeability - ✔✔Degree to which fluids travel may through a rock
✔✔Geologic formation oil traps - ✔✔1. anticline traps
2. fault traps
3. salt dome traps
✔✔Anticline trap - ✔✔Oil pools at the top of anticline and is trapped by a seal rock
✔✔Fault trap - ✔✔Reservoir rock may be faulted up against an Impermeable rock.
✔✔Salt dome trap - ✔✔Oil/Gas found between impermeable shale and an impermeable
salt dome.
✔✔Stratigraphic trap - ✔✔changes in rock permeability, porosity due to patterns of
different sediment deposition
✔✔Fracking is used to what end in the extraction of natural gas + oil - ✔✔It allows for
increased permeability by fracturing the ground
✔✔How are tar sands formed? - ✔✔Oil reserves that are subjected to microbial
degradation become tarsands.
✔✔How is coal formed? - ✔✔Derived from ancient plant matter that has been buried,
compacted and 'cooked' to remove N, O, S, H, leaving only carbon
✔✔What are the various stages of coal? - ✔✔Lignite (70% C)-> bituminous coal (85%
C) -> Anthrasite (95% C)
✔✔If coal deposits are too hot/ too deep, we have... - ✔✔graphitization
