Final REview Guide: Geo
Terms
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- Quartz
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⬢ Hardness of 7
⬢ 3D framework silicate
⬢ No cleavage plans
o Conchoidal Fractures
- Feldspar
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Hardness: 6
2 Cleavage planes
3D framework silicate
Forms under a wide range of temperatures and pressures - Calcite
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Hardness of 3
3 cleavage planes
reacts with acid - Mica
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Hardness of 3
1 Cleavage Pane
Sheet Silicate - Gypsum
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Harness of 2
Can scratch if with your finger nail
3 Cleavage planes - Hornblende
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Hardness of 5
2 Cleavage Planes
Double chain silicate - Halite
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Hardness of 2.5
2 cleavage planes
Salty taste
Cubic Structure - Galena
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Hardness of 3
Cubic cleavage planes (breaks off in cubes)
Realllly heavy - Talc
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Hardness of 1
Can be scratched with a fingernail
1 cleavage plane - Granite
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Forms deep underground
Phaneritic rock (coarse-grained)
Felsic - Rhyolite
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Forms at the surface
aphanitic (fine grained)
Felsic - Basalt
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Forms at the surface
Aphanitic (fine grained)
Mafic
Can be vesicular, has holes - Gabbro
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Forms deep underground
Phaneritic (coarse grained)
Mafic - Obsidian
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Forms at the surface when lava comes into contact with water
Glassy
Conchoidal fracture - Pumice
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Formed from composite volcanoes
Rough glassy
Floats in water
Porus
Felsic - Diorite
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Forms deep underground
Phaneritic, coarse grained
Intermediate - Andesite
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Forms at the surface
Aphanitic, fine grained
Intermediate - Sandstone
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Formed when sand lithifies together
Forms at sand dunes, beaches and oceans
- Greywacke
- Grey sandstone, forms in the oceans when sand and dirt mix in together and lithify
- Shale
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formed when mud, clay and silt compact together
Found in lagoons, deltas, shallow seas, lakes - Conglomerate
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Formed when rounded pebbles, cobbles, gravel and sand cement together
Found in high velocity streambeds - Breccia
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Formed when angular pebbles, cobbles, gravel and sand cement together
Found at the base of a mountain in an alluvial fan, glacial deposits - Limestone
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Formed from calcite
found in oceans, deep seas (chalk), coral reefs (coquina) - Coal
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Formed from organic materials and mud, clay and silt
Found in swamps
Used for oil - Gneiss
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foliated rock
Can form from slate, shist, shale or volcanic rocks - Shist
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foliated rock
can form from slate, mudstone, siltsone, shale - Slate
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foliated rock
forms from shale - Quartzite
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Non-foliated rock
Forms from quartz sandstone - Marble
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Non-foliated rock
Forms from dolostone, limestone - Convergent Plate Boundaries
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Result of compression formed when two plates push together
Often results in the creation of subduction zones
Can be ocean to ocean
Ocean to Continental
or continental to continenatl - How does compression get created
- When two plate boundaries push together. Can result in subduction zones
- Subduction Zones
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Result of Compression of a convergetnt boundary
Forms composite volcanoes - Composite Volcanoes
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Felsic magma, pyroclastic flows
Granite, Rhyolite, Pumice, Diorite, Andesite
Example: The Andes - Continental to Continental Convergence
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Resulting in mountain ranges
I.e. Himalayas - Divergent Plate Boundaries
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When two plate boundaries pull apart causing tension
Results in mid-ocean ridges and rift valleys - Mid-Ocean Ridges
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Result of tension caused by a divergent boundary
Really mafic magma
Ex: basalt, gabbro, peridotite, obsidian
Ex: The ring of fire is a mid-ocean ridge spreading apart from a divergent boundary creating new ocean floor - Sea-floor spreading
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Occurs at a mid-ocean ridge
Where new sea-floor is created - Transform plate boundaries
- When two plate boundaries move passed each other creating sheer stress
- Sheer stress
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When two plate boundaries move past eachother
Causes transform faults - Shield Volcanoes
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Enormous, gently sloping
Basaltic lava
Creates Aa or Pahoehoe volcanoes - Aa lava
- A type of lava flow with a jagged or rocky surface
- Pahoehoe
- A type of lava flow with a smooth, pillowy surface
- Cinder Cones
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Built from ejected lava fragments
Normally a one eruption volcano
Erupts with a pyroclastic flow - Caldera
- A large depression typically formed from the collapse of a magma chamber from a volcano following a violent eruption
- Extrusive Rock
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Igneous rock formed on the surface, normally Aphanitic
obsidian, basalt, pumice, andesite, rhyolite - Intrusive Rock
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Igneous rock formed on the surface, normally Aphanitic
Obsidian, basalt, pumice, andesite, rhyolite - Porphyritic Rock
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An igneous rock containing both Phaneritic and Aphanitic crystals
Created when rock that has already formed large crystals deep underground is erupted resulting in the creation of fine-grained crystals forming around it
Phenocrysts are teh larger crystals - Dike
- An igneous intrusion that cuts across sediment layers
- Sill
- an igneous intrusion that runs in accordance with sediment layers
- Batholith
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the largest intrusive body
typically granite - Volcanic Neck
- Remnant of a volcano that has been eroded away leaving pieces behind
- Valley/Alpine Glacier
- a glacier confined to a mountain valley which had previously been a stream valley
- Continental glacier
- An enormous glacier covering hundreds of miles of land, most commonly found during the Pleistocene Ice Age
- Firn
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The coarse grained, sand-like crystallization of snow (one step before freezing completely)
Layer after layer firn gets compacted and compressed solififying into glacial ice - Advancing glacier
- A glacier that continues to grow and move down the valley
- Receding glacier
- As temperatures begin to drop and ice begins to melt glaciers retreat
- Crevasse
- When the glacier moves the zone of fracture is subjected to tension resulting in cracks
- Does the top or bottom of a glacier move faster?
- The Top moves faster
- Glacial Till
- The sediment, often angular and unsorted, that is deposited by glaciers. Most commonly breccia
- Terminal Moraine
- the till deposited at the terminus of a glacier
- Lateral moraine
- the till deposited along the sides of a glacial valley
- Medial moraine
- As a tributary glacier joins another glacier the till that is combined when the two meet is medial moraine
- Glacial Erosion
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2 Ways-- abrasion and plucking
Striations can be formed when the bottom of the glacier moves across teh bedrock
- Striations
- Long marks carved into the bedrock as a result of the bottom of a glacier moving across the bedrock
- Drumlins
- Streamline asymmetrical hills composed of till
- Eskers
- Ridges composed largely of sand and gravel
- Erratics
- random placed rocks that were brought to its present location by a glacier while it was moving and then melted leaving it exposed
- Icebergs
- pieces of glaciers that fall off into a body of water
- Abrasion
- as the ice travels over the bedrock it acts as a sandpaper scraping and glossing the rock below it
- Earthquake
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-Vibration of earth produced by the rapid release of energy
-Result of tension built up in a fault - Fracture
- break in the rock
- Joint
- break in the rock but no movement occurs
- Elastic rebound theory
- rock elasically returns to its orginal shape and springs back
- Aftershocks
- result of the adjustments in the Earth following a larger earthquake
- Foreshocks
- smaller earthquakes that precede a larger, major earthquake
- Dip-Slip Fault
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A fault that occurs vertically, along a dip
- Normal Dip-Slip Fault
- hanging wall moves down, footwall moves up
- Reverse Dip-Slip Fault
- Hanging wall moves up and the footwall moves down
- Strike-Slip Fault
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A fault that occurs horizontally, along a strike
Earth either moves to the left or the right - Right-lateral strike-slip fault
- When earth shifts to the right
- Left-lateral strike-slip fault
- when the Earth shifts to the left
- Thrust Fault
- Dip-Slip fault along which no scarp is produced
- basin and range
- fault-block mountains with a down dropped basin called "graben" and an uplifted section called "horst"
- Seismograph
- When the built up energy is released waves and produced and measured by a seismograph
- Body Waves
- Trael thru the first waves to arrive, they push (compress) and pull (expand) rocks in the direction the wave is travelling
- S-Waves
- second to arrive, they shake at right angles to the direction they travel, more destructive than p-waves
- Intensity
- ammount of damage that the earthquake creates at a location
- The Richter Scale
- estimates the magnitude of an earthquake
- Magnitude
- Ammount of energy that is released by the earthquake
- Epicenter
- Center of quake above the surface, above the focus
- Tsunami
-
disastrous result of earthquakes
massive wave of water caused by large undersea earthquakes - Drainage Basin
- land area that contributes water to a river system
- Drainage divide
- The imaginary line that seperates one drainage basin to another
- Discharge
- The volume of water flowing past a certain point in a given unit of time
- Dissolved Load
- portion of a stream load carried in a solution
- Suspended load
- fine sediment carried within a body of flowing water
- Bed load
- sediment rolled along the bottom of a stream by moving water
- Saltation
- Sediment appears to jump or skip along the stream bed
- Sorting
- degree of similarity in particle size in sediment
- What happens when a stream enters still water of an ocean
- Velocity drops, resulting sediment forms a delta
- Braided streams
- form when gravel deposition builds in the center of a stream causing a part in it.
- Natural levees
- built by successive floods over a period of time which deposit coarse grained sediment right at the banks of the river
- V-shaped valley
- when a river is young it forms a v-shaped valley and as it runs along this valley it laterally erodes
- Meander
- Loop-like bend created as the river matures