GEOL 404: EXAM 1
89 Cards in this Set
Front | Back |
---|---|
A regression occurs when?
A) sea level is falling
B) sea level is rising
C) sea level rises faster than the land is uplifted
D) none of the above
|
A) sea level is falling
|
A transgression occurs when?
A) sea level is falling
B) sea level is rising
C) sea level rises faster than the land is uplifted
D) none of the above
|
B) sea level is rising
|
Define "Structural Cross Section" and "Stratigraphic Cross-Section"
|
* Structural Cross Section reveals the true positions and true vertical depth of rock layers and deformation structures
*Stratigraphic cross section shows depositional variations of rock layers without deformation structures and without revealing the true depth
|
Type of map: Depth contours of a subsurface formation
A) Structural Contour map
B) isopach map
C) isochore map
|
A) Structural contour map
|
Type of map: shows contours of true stratigraphic thickness of a formation
A) Structural Contour map
B) isopach map
C) isochore map
|
B) Isopach Map
|
Type of map: Contours of true vertical thickness of a formation
A) Structural Contour map
B) isopach map
C) isochore map
|
C) isochore map
|
What is the environment that corresponds to "ALLUVIAL" deposition?
|
Continental
|
What is the environment that corresponds to "FLUVIAL" deposition?
|
Continental
|
What is the environment that corresponds to "DELTA" deposition?
|
Transitional
|
What is the environment that corresponds to "LAGOON AND REEF" deposition?
|
Marine
|
Turbidites are deposited in?
A) Alluvial Environment
B) Fluvial Environment
C) Beach Environment
D) Shallow water carbonate platform
E) Deep marine fan
|
E) Deep marine fan
|
What is the environment that corresponds to "REEF" deposition?
|
High wave energy
|
What is the environment that corresponds to "PLATFORM SLOPE" deposition?
|
Low wave energy
|
What is the environment that corresponds to "LAGOON" deposition?
|
Medium wave energy
|
The closer to a hydrocarbon reservoir, the salinity of the connate water tends.....
A) to be higher
B) to be less
C) to remain the same
|
A) to be higher
|
Gas is said to be "sweet" or "sour", based on the absence or presence of?
A) H2S
B) CO2
C) N2
|
A) H2S
|
What are the major effects of subsidence due to basin fills on sediments?
A) Porosity reduction
B) Permeability Reduction
C) Pressure increase
D) Temperature increase
E) All of the above
|
E) All of the above
|
Which of the following sequences will most likely result in a petroleum accumulation? from beginning to end
A) source rock, deposition of reservoir, formation of structural trap, maturation and migration, overburden rock
B) source rock, reservoir, seal, overburden rock, structural t…
|
B) source rock, reservoir, seal, overburden rock, structural trap, maturation and migration
|
Earth's lithosphere is broken into large plates. the 3 major kinds of plate boundaries are...
|
Divergent Margin, Convergent margin, and transform margin
|
MC: What is the major cause for the movement of tectonic plates?
A)Rapid convection in liquid outer core
B) slow convection in solid mantle over geologic time
C) Earthquakes
D) Volcanoes
|
B) slow convection in solid mantle over geologic time
|
Which of Earth's layers corresponds to "AUGITE (PYROXENE) AND OLIVINE WITH NO FELDSPAR" composition?
A) Core
B) Mantle
C) Oceanic crust
D) continental crust
|
B) Mantle
|
Which of Earth's layers corresponds to "HIGH SiO2, K2O, AND Na2O" composition?
A) Core
B) Mantle
C) Oceanic crust
D) continental crust
|
D) continental crust
|
Which of Earth's layers corresponds to "BASALT AND GABBRO" composition?
A) Core
B) Mantle
C) Oceanic crust
D) continental crust
|
C) Oceanic crust
|
Which of Earth's layers corresponds to "Fe AND Ni metal" composition?
A) Core
B) Mantle
C) Oceanic crust
D) continental crust
|
A) Core
|
Which rock corresponds to the mineral "CLAY"?
A) Shale
B) Sandstone
C) limestone
D) Dolostone
E) Granite
F) Basalt
|
A) Shale
|
Which rock corresponds to the mineral "QUARTZ"?
A) Shale
B) Sandstone
C) limestone
D) Dolostone
E) Granite
F) Basalt
|
B) Sandstone
|
Which rock corresponds to the mineral "CALCITE"?
A) Shale
B) Sandstone
C) limestone
D) Dolostone
E) Granite
F) Basalt
|
C) limestone
|
Which rock corresponds to the mineral "DOLOMITE"?
A) Shale
B) Sandstone
C) limestone
D) Dolostone
E) Granite
F) Basalt
|
D) Dolostone
|
Which rock corresponds to the mineral "MICA, FELDSPARS"?
A) Shale
B) Sandstone
C) limestone
D) Dolostone
E) Granite
F) Basalt
|
E) Granite
|
A) Shale
B) Sandstone
C) limestone
D) Dolostone
E) Granite
F) Basalt
|
F) Basalt
|
Types of Faults?
|
*strike-slip fault
*transform fault
*normal fault
*reverse fault
*etc
|
Folds and reverse faults in a mountain belt suggest?
A) Compressional Stress
B) Volcanoes
C) Tensional stress
D) All of the above
|
A) Compressional stress
|
Which of the following minerals can be transported a long distance by water without being dissolved or broken down?
A)Orthoclase (K-spar)
B) Calcite
C) Quartz
D) plagioclase
|
C) Quartz
|
What is the correct order of grain size deposition when moving from "close to the source" to "far away from the source"?
|
1. Pebbles
2. Very coarse sand
3. Coarse Sand
4. Medium sand
5. fine sand
6. very fine sand
7. silt
8. clay
|
What region corresponds to "BOUNDSTONE, and GRAINSTONE" rocks?
A)reef
B) slope
C) lagoon
|
A)reef
|
What region corresponds to "PACKSTONE, WACKESTONE, and MUDSTONE" rocks?
A)reef
B) slope
C) lagoon
|
B) slope
|
What region corresponds to "PACKSTONE, and WACKESTONE" rocks?
A)reef
B) slope
C) lagoon
|
C) lagoon
|
List the 5 major steps of the wilson cycle in the order of their occurence.
|
1) continental rift-New Young Basin
2) Passive margin boundaries-strike slip
3) Ocean closing- island arc formation
4) island arc- continent collision
5) Continent-continent collision
|
What are Hydrocarbons?
|
*Made of complex molecules of hydrogen and carbon
*Organic matter is chemically transformed into hydrocarbons
|
Petroleum system:
|
source rock, reservoir rock, seal, trap, maturation and migration
|
What are the 4 levels of petroleum investigation? from level of assessment
|
1)Sedimentary Basin
2) Petroleum system
3) Play
4) Prospect
|
What is a gas hydrate?
|
*12-sided cages (dodecahedrons) with gas molecules inside results in a stable crystalline structure at proper temperature and pressure
*A unit volume of methane Hydrate stores > 160 volumes of free gas equivalent at STP
*are crystalline water-based solids physically resembling ice, in w…
|
What is the cause of Earth's magnetic field?
|
Rapid convection in the liquid outer core
|
What causes plate movement?
|
Slow convection in the solid mantle
|
Types of Margins?
|
1. Divergent
2. Convergent
3. Transform
|
Explain Divergent Margin...
*Motion:
*Effect:
*Topography:
*Volcanic Activity?:
|
*Motion: Spreading
*Effect: Constructive
*Topography: Ridge/Rift
*Volcanic Activity?: Yes
|
Explain Convergent Margin...
*Motion:
*Effect:
*Topography:
*Volcanic Activity?:
|
*Motion: Subduction
*Effect: Destructive
*Topography: Trench
*Volcanic Activity?: Yes
|
Explain Transform Margin...
*Motion:
*Effect:
*Topography:
*Volcanic Activity?:
|
*Motion: Lateral sliding
*Effect: Conservative
*Topography: no major effect
*Volcanic Activity?: No
|
Examples of a Convergent margin....
|
*Arabian Plate and Eurasion Plate Boundary
*Pacific Plate and Eurasian Plate
|
Examples of a Divergent margin....
|
*Arabian Plate and African Plate
*Eurasian Plate and North American Plate
|
Examples of Transform margin...
|
Scotia Plate
|
Decompression Melting process...
|
*hot rocks move into area of lower pressure without losing heat
*occurs in upper mantle below spreading centers (divergent plates)
*Occurs where mantle material rises to hot spots or plume
|
What crust?
*mafic
*denser, younger
*High thermal gradient
*Basalt/Gabbro/olivine
|
Oceanic Crust
|
What crust?
*Felsic
*lighter, thicker, old
* low thermal gradient
*rhyolite/granite/quartz/mica
*K,Al,Ca,Na,SiO4
|
Continental Crust
|
Continental Rifting
|
*Break up o continental lithosphere (weaker than ocean crust)
*Breakups form graben (normal/listric faults)
*sediments deposit in graben
|
Hydration
|
*water added to lower melting temp of mantle
*occurs at sinking ocean crust
|
Mineral Groups
|
*Silicates (quartz, olivine, feldspar, clay)
*Carbonates (calcite, dolomite)
*Sulfates (gypsum)
*Halides (salt)
*Oxides
|
Contact Metamorphism
|
*increasing porosity
*Chlorite/ Amphibole/ epidote/ garnet/ pyroxen/ hornfels
|
Carbonate Rocks
|
*limestone (calcite)
*dolostone (dolomite)
|
Sedimentary Process
|
1. Weathering/Erosion
2. Transport
3. deposition
4. lithification
|
hydrolosis
|
*dissolution of minerals carbonic acid
*hydrogen ions replace rock
|
Stable minerals
|
*Quartz
*Muscovite
*Clay
|
Clastic Deposition (bedforms)
|
*low velocity: ripples (small cross bedding)
*Medium velocity: dunes (large cross bedding)
*High velocity: planar bed (horizontal stratification)
|
Carbonate Deposition
|
*high wave energy: platform edge (reef) "boundstone, grainstone"
*medium wave energy: lagoon "wackestone, packstone"
*low wave energy: platform slope "wackestone, mustone"
|
Biochemical Rock
|
*Diatoms/radiolariums remove Si from water to make shells (chert)
|
Transitional Deposition
|
*Sabkha: stranded ocean
*strand: beach
*delta: river outlet
*littoral:
|
Marine Deposition
|
*sublittoral: shelf
*lagoon
*Buthynl: slope
* Abyssal: deep ocean
*Hadal: trenches
|
Alluvial Fans
|
*cone shaped body of sediment: stream enters valley, shape created by shifting channels
*coarse grains at top of fan
|
Sabkha
|
*tract of land with high evaporation
*occurs in hot climate between desert and shore
*Percipitates: gypsum, salt, halite, calcite
|
Braided Stream
|
*interlaced tangled streams
*common between alluvial fan and meandering stream
*occurs from river fluctuation/ erodible banks
|
Meandering Stream
|
*single confined stream (low gradient)
*particle size decreases downstream
|
Delta Deposition
|
*river enters large body of water
*high accumulation
*good sorting
*major petroleum reservoir in clastics
|
Beach Deposition
|
*clastic
*sand is deposited parallel to slightly inclined layers
|
Deep Marine Deposition
|
*Deep marine fans
*deposition of turbidites (graded beds) from density currents
|
Stratographic Sequences (length)
|
*continental rifting (>50 my)
*Plate movements (3-50 my)
*uplift, subsidence (.5-3 my)
climatic cyclic event (10,000-50,000 years)
|
Regression
|
*sea level retreats (deposition: sandstone on top, mudstone on bottom)
|
Transgression
|
*increase sea level (deposition: Mudstone on top, sandstone on bottom)
|
Types of folds
|
*Anticline: Petroleum tram (upwards dome shape)
*Syncline: (U shape)
*Monocline: minor fold
|
Affect of (T, P) on deformation
|
*15-20 km gives way to ductile
*few deep earthquakes/faults (too hot to break: except in subduction zone)
*water weakens rock: increase ductility
|
Know Normal Fault
|
*caused by tension
**PICTURE**
|
Know Reverse Fault
|
*caused by compression
**PICTURE**
|
Know Thrust Fault
|
*caused by compression (shortening of crust by .5-20-750 km)
**PICTURE**
|
Listric Fault
|
*fault plane becomes closer to horizontal with depth
*normal and thrust can be listric
**PICTURE**
|
Strike Slip Fault
|
*horizontal movement
**PICTURE**
|
Deformations in Rocks
|
*folds: bent structures (ductile deformation)
*Faults: brittle with offset
*Fractures: brittle with no offset (result from bending/stress/cooling volcanic rock
|
Structural Cross Section
|
*shows depth using sea level TVD
*Shows rock layer position and deformation
*used to show potential traps
|
Stratigraphic Cross-Section
|
*hung along a reference surface (subsurface marker)
*shows layers as originally deposited and how they relate
*NO deformation!!!!!
|
Net Sand Map
|
*Contours sand: shale ratio of formation
*also called reservoir quality map
|
Net Pay Maps
|
*contours gross pay to net pay ratio
*gross pay: total vertical interval from top to bottom
*Net pay: cumulative thickness from where petroleum can be produced
|