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69 Cards in this Set
- Front
- Back
Geological Principles: Uniformitarianism |
Processes operating at the present are the same processes that have operated in the past. |
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Geological Principles: Original Horizontality |
Beds of sediment deposited in water were formed as horizontal of nearly horizontal layers. Normal for most sedimentary rocks. |
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Geological Principles: Superposition |
The layers of undistributed sedimentary rocks get younger going from bottom up. Oldest--> youngest. |
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Geological Principles: Principle of Lateral Continuity |
Usually sediments will accumulate as continuous sheets in an area. Subsequent erosion can remove materials making them discontinuous. |
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Geological Principles: Cross-Cutting Relationship |
The disruption (folding/tilting) is younger that the original layering of the rocks. |
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Geological Principles: Principle of Fossil Succession |
Fossils are the preserved remains or traces of organisms from the past. |
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Geological Principles: Inconclusions |
Fragments of rock unit that are found within another rock unit. |
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Stratigraphic Column |
A vertical cross-section where the rock layers are divided into stratigraphic fragments. |
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Unconformities |
Rock layers that are deposited over time mainly without interruptions are said to be conformable beds. (GAP IN TIME) |
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Unconformities- Three Types 1. Angular |
Where the tilted beds underlies a horizontal bed. |
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Unconformities- Three Types 2. Non-conformity |
Where a break in time occurs between older metamorphic or igneous rocks and younger sedimentary rocks. |
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Unconformities- Three Types 3. Disconformity |
Where a gap in time is not readily apparent with horizontal beds on either side. |
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Metamorphic Rock |
Are formed by the transformation of pre-existing rock by high pressure, temperature, or chemically active fluids. |
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Foliated Rocks |
Occur when there is pressure and the composition of the rock includes minerals such as mica. Platy mineral, layered look. |
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Non-Foliated Rocks |
Occur when the pressure is low or not a factor or the composition of the rocks does not include platy minerals such a mica. Marble. |
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Deformation |
The changes in size or form of a rock that occurs when subjected to forces greater than its strength. |
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Force |
A force is any influence that causes a free body to undergo an acceleration. |
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Pressure |
A type of stress. |
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Differential Stress |
Describes when stress is unequally applied. |
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Compositional Stress |
Occurs with collisions when plate margins come together, causes folding and some faulting. |
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Tensional Stress |
When plate margins or rocks are pulled apart. Results in faulting. |
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Shear Stress |
Slippage, rock surfaces of plates sliding past each other. Stress that acts parallel to a surface. |
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Deformation is Depedent on? |
Speed- Slow speed, the rock deforms elastically and can snap back to original shape. Rock Type- Some are brittle, some can bend. Location- Often fractures occur in rocks near the surface with low confining pressure and temp. |
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Strike and Dip Box |
Water flows down an inclined surface parallel to the dip. The strike is always 90' to the dip. |
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Dip |
Angle of the inclined surface from horizontal (45') |
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Strike |
The compass bearing of a horizontal surface when intersects an inclined surface. |
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Anticlines |
The upfolded parts of the rock layers (arch). |
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Syncline |
The down folded parts of the rock layer (trough). |
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Faults |
Fractures along which there has been some movement. |
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Hanging Wall |
The wall directly above the fault line. |
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Foot Wall |
The wall directly below the fault line. |
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Fault Surface (PLANE) |
The fracture surface between one block and another along which movement occurs. |
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Focus |
Origin of the earthquake, the point within the crust where movement first occurred. |
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Body Waves |
Travel through the earths interior. P-waves (primary) push waves, and S-waves (secondary) up and down. |
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Surface Waves |
Travel through the lithosphere. Love waves and Rayleigh waves. Form from unexpended P and S waves |
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P-Waves |
Push waves, compression waves, the first to be detected at a recording station. Velocity 4-10km/sec. Transmit through solid of fluid material. |
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S-Waves |
Shear waves, a shearing motion only goes through rock material. Velocity 2-5km/sec. |
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Mercalli Intensity Scale |
Perceptions by people near the epicenter, therefore is subjective. has 12 degrees of intensity. |
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Richter Scale |
Based on the maximum amplitude of seismic waves (P/S) and to distance. |
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Movement Magnitude (Mw) |
Expresses the total energy released over the entire fault zone and the volume of rock involved. |
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Six Volcanos/Eruption Types 1. Flood Basalts |
Made of basaltic lava. Very fluid, ejected from a fissure, and the low viscosity lava floods over the land. |
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Six Volcanos/Eruption Types 2. Shield Volcanos |
Largest Volcanos. Form from basalt, gentle slopes (5'-12'). Eruptions via fissures and vents. |
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Six Volcanos/Eruption Types 3. Cinder Cones |
A small volcano cone. The slope angle is approx. 24'-32' to the horizontal. |
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Six Volcanos/Eruption Types 4. Composite Cones or Stratovolcanos |
Intermediate in size, variable slope angles. |
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Six Volcanos/Eruption Types 5. Caldera |
A volcanic crater that develops from the explosion and collapse of a composite volcano. |
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Six Volcanos/Eruption Types 6. Other |
Lava Domes- Lava flows quickly and piles up at vent. Splatter Cones- Very small. Volcanic Plugs- Lava cools and plugs the vent. |
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Weathering Processes 1. Frost Wedging |
Block fields surface with angular blocks likely due to weathering. |
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Weathering Processes 2. Thermal Expansion |
Heating and cooling results in differential expansion and contraction. Stresses the rock and eventually breaks the bonds within the rocks. |
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Weathering Processes 3. Salt Crystal Growth |
Occurs in arid regions, and marine coastlines. |
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Weathering Processes 4. Plant Wedging |
Seed exploits crack in rock as root grows it exerts force on surrounding rock. |
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Six Main Weathering Processes 1. Dissolution |
Dissolving of solid rock material in water. Not a permanent process. |
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Six Main Weathering Processes 2. Carbonation |
Water and Co2 combine to form a weak acid that is effective on certain rock groups. |
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Six Main Weathering Processes 3. Hydration |
The absorption of water molecules in the mineral molecules. Results in swelling of rock and disruption of structure. |
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Six Main Weathering Processes 4. Hydrolysis |
The absorption of water by a rock to form a new material. |
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Six Main Weathering Processes 5. Oxidation |
Formation of rust. |
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Six Main Weathering Processes 6. Chelation |
Rocks decomposed by the action of organic acids produced by organisms. |
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Soil |
Soil = f (CLORPT) + HI Climate, organisms, relief, parent material, time, and human impact. |
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Zone of Leaching |
Removal and transportation of soil mineral in suspension and/or in solution within the soil by downward or lateral movement of water. |
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Zone of Accumulation |
Where ion and clays accumulate. |
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Illuvation |
Depositional processes of soil material that has been transported from one horizon to another. |
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Mass Wasting |
Based on rate of movement, type of material, and type of movement. |
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Mass Wasting Movement 1. Creep |
Slowest type of movement by gravity of any type of material. Very widespread, imperceptible. |
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Mass Wasting Movement 2. Flow |
Materials on a slope becomes saturated with water, from heavy rain/snow melt and material is liquified leading to fluid deformation. |
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Mass Wasting Movement 3. Slide (slip/slump) |
Occurs on a very steep slope where materials slide along a well defined shear zone. |
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Mass Wasting Movement 4. Fall |
Free fall of materials detached from steep surfaces (cliffs), little contact with face once launched, so reaches high speeds. |
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Geological Time Scale |
Geological events are placed into a chronological (absolute time) and hierarchical framework (relative time). |
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Geological Time Periods Pretty Cold Oysters Seldom Develop Coloured Pearls, Their Juices Congeal Too Quickly |
Pre-cambiran, cambrian, ordovician, silurian, devonian (develop), carboniferous, permian, triassic, jurassic, cretaceous, tertiary (mammals), quaternary. |
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Absolute Age |
Actual age/ time in years (carbon dating). |
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Relative Age Dating |
The relative order of events within a sequence. |