Study Guide Test 2 Flashcards
Magma Differentiation
process that changes magma’s chemistry towards a more felsic composition over time
fractionation and assimilation
Fractionation
Magma composition erodes as mienrals crystallize out- remaining melt becomes silica rich and felsic
mafic to felsic
Burial Meta
Rock deeply buried 7200 m
Deep sedimentary basins
Extension of diageneis
Increasing temp, CONFINING pressure at depth- low grade- zeolic facus
Quartz sandstone- quartzite
Pegmatitic
very slow crystallization
Bedding Planes
Sedimentary material or deposition in horizontal layers forming beds
Beds are bigger than 1 cm thick
Defined by differene in color, sediment size, and/or resistance to erosion
A different bed incidactes change in sediment deposition conditions
texture
crystal grain size
Magma compositions of Calderas
Intermediate to felsic comp
Chemical Sedimentary rocks classification
organic
inorganic
biochemical
Inorganic Sedimentary- Banded Ions Formations
iron oxide precipitated from ocean water depositing on ocean floor in concentration bands, alternating with chert
Pressure Solution
Material is dissolved from highly stressed edges of grains
Styolid- pressure solution streams
Inorganic Sedimentary Rocks - Inorganic Chert
Microcrysyalline quartz precipitated out of silica rich groundwater
Jasper, Flint, Onyx, Agate
Fossiliferous limestone
abundant visible fossiles (marine invertebrates)
Coral reefs, shallow ocean setting, lakes
How does crystal size and metamorphic fabric (foliation degree) relate to metamorphic grade?
Smaller crystal size- low
Bigger crystal size- high
Foliation- high
Non-foliation- low
Rotation
Elongated and platy minerals can rotate so they become almost parallel to one another
Minerals that crystallize or grow in the differential stress field can have a preferred orientation
Schistosity- mica and other minerls with dominant orientation
Coal
large quantities of plant debris in wetlands/swamplands decays to peat and alters into an organic sedimentary rock
Order of Bowen’s reaction series
Ultramafic, Mafic, Intermediate, Felsic
Igneous Dikes
intrustion that cuts across the layer
vertical
6 different types of volcanoes
Cinder/Scoria Cones
Shield Volcanoes
Stratovolcanoes
Lava Domes
Calderas
Flood Basalts
Foliation Texture
A planer alignment of minerals and textures within a rock
Line on plane with no common direction
what controls magma viscosity
Magma Composition and temperature
compaction
pressure of overlying sediments decrease pore space between the grain
A sedimentary rock which contains environmental clues, such as grey-green mudstones with laminations and freshwater fossils, would mostly likely indicate which depositional environment?
lacustrine (lake)
Magma compositions of Flood Basalts
low viscosity
Basalt lava flows
Volcanic Hazards
Gases
Tephra
Pyroclastic Flow
lahar
Landslide
Tsunamis
Hot Spot has what type of igneous rock comp
oceanic- mafic to intermediate
continetal- mafic to felsic
Which statement is INCORRECT about Peridotite?
It is composed of an abundance of feldspar and quartz minerals.
Heat induced Melting
INCREASE in temp
melting of surrounding rocks from magma intruction of rising mantle plume
MANTLE PLUME
HOTSPOT
In what environments does low pressure/high temperature metamorphism occur
near magma intrustion at shallow depth
Mudstone
general term for fine grained sedimentary rocks
Transgressions
Rise of sea level and submergence of the continent under seawater
Depositional environments shift landwards (go further towards land, ocean expanding)
Difference between metamorphic texture and igneous texture
Metamorphic-
Descriptin of mineral grain shapes and orientation
Foliated or nonfoliated- granular, equi distance
Line up or not
Igneous
based on grain size and other features
cooling rate big influence
magma textures
Continental Subduction has what type of igneous rock comp
Ultramafic rock
mafic melt
Effusive Eruption
Non-explosive eruptions
low gas and low viscosity
lava dome and lava flow
Deltas
Transitional - Where rivers enters oceans
Three types- river delta, wave delta, tide dominated delta
Main sediment: channelized sand, mud, organic matter (swamp)
Main rock- clastic rocks, coal/organic sedimentary rocks (swamps)
Main structure- cross bed, delta seidments, sequence (muds to fine sand to coarse sands and organic rich rocks)
Main fossils- many to few fossils
What is incorrect about Batholiths
Most mafic in comp
How is temperature and pressure involved in metamorphism?
Temperature
Heat driven metamorphism occurs at 200 and continues until 700-1100
Pressure
Force exerted over an area, stress= applied force
Strain is product of stress/metamorphic dchanges within minerals
What are two things that influence initial magma compositions
Source of rock
degree of partial melting
True/False
Occasionally fine-grained sediments of the abyssal plane near continental slopes can contain courser sand-sized sediment carried by submarine landslides called turbidite deposits.
true
metamorphic grade
range of metamorphic change a rock undergoes, progressing from low (little metamorphic change) grade to high (significant metamorphic change) grade.
What does grain size, sorting, and clast shape indicate and environemtn distance
grain size- as size gets smaller, longer transport time
sorting- more well sorted the rock is, longer the distance
shape- rounder (smoother) it is, the longer the distacance
Shearing
Shear stress causes objects to be smeared out in the direction of applies stress
Augens- eye shaped
Bioturbation
Reworking of soft sediment by burrowing organisms
SHALLOW MARINE environments
Used to indicate WATER DEPTH
why are caldera, flood basalts, volcanic dome, stratovolcano more dangerous than scoria or shield
Scoria and Shielf- localized eruptions
Others- explosive eruptions that are far reaching
Composition
what minerals are present
Clastic Sedimentary rocks classification
Breccia
conglomerates
sandstones
mudstone
shale
Dunes
Meter Scale Ripples
Igneous rocks are classified based on which
texture
composition
True or False:
The presence of pillow basalts indicate lava flowed within a body of water.
true
Assimilation
incorporates the host rock that magma is intruding into
piece of surrounding block gets added to melt/magma, pieces partially melt
Contact meta
High temp low pressure
Local, small instruction
Shallow depth
Produce NON-FOLIATED rocks
Heat from magma alters rok in comes in contact with (heating, NO deformation)
What metamorphic rocks are diagnostic of subduction metamorphism?
Greenstone, greenschist, blueschist, eclogice
Inorganic Sedimentary rocks- rich groundwater
abundant dissolved ions precipiate out of solution-
lakes streams hot spring, caves
stalagmaite and stalactite
Physical processes metamorphism
Deformation of objects
Rotation
Shearing
Ultramafic
Mantle rocks
Contains MOST of Fe, Mg, and Ca
LEAST amount of silica
Periodite- intrusive
Kmoatite- Extrusive
Biochemical
formed from shells/skeletons of marine/freshwater organisms
Organisms extract dissolved material out of water to form shells, when dies, the hard parts deposit on sea floor as sediment that lithifies when buried
fossiliferous limestone
chalk
biogenic chert
stromatolites
true/false
The metamorphic rock, mylonites, are associated with fault metamorphism where fault shearing occurs at deeper depths.
true
Why does contact metamorphism produce only non-foliated metamorphic rocks?
No pressure that foliated one need
Inorganic Sedimentary rocks high evaporation rate
cause bodies of water to dry up
Dissolved ions precipitation out of solution
Forming evaporate minerals
Salt, calcite, gypsum, halite
Three ways magma can form
Decompression Melting
Flux Melting
Heat Induced Melting
Partial Melting
different minerals make up rocks, minerals melt at different times
Resulting melt more felsic
increase from ultramafic to mafic- felsic melts from rock sooner
Lacustrine
Continental- Lakes
Low energy environment
Main sediment- fine-grained
Main rock- shale
Main structure- lamination
Main fossil- freshwater organisms
Tephra
ash
explosive eruption produce it and the wind carry it long distances
WIth enough- collapse buildings, cause Silicosis (respiratory issues)
Explosive Pyroclastic Eruption
Explosive eruption
high gas and high viscosity
lava fountaining, pyroclastic flow, eruption channel + ash cloud
Pyroclastic Flow
fast flow of lava blocks, pumice, ash, and hot gases
collapse of eruption column or lava dome
MOST DANGEROUS
STRATOVOLCANO or LAVA DOME
what gives igneous rocks fine grained, aphanitic texture
When a lava has a fast cooling rate,
Biological Activity
Root wedging- plant roots work themselves into cracks, prying the bedrock apart as they grow
tunneling organisms like earthworms, termites, and ants
Graded Bedding
Change in grain size within a sediment bed
Trends from coarse to finer; or finer to coarser
Caused by changes in currents speed
Events like FLOOD, LANDSLIDES, SUBMARINE LANDSLIDES
Fault Meta
Fault where reach duxtile zone- shear rock
Mylongic form- created by dynamic recrystallization through directed shear forces
Larger, stronger mineral crystals may form augments
Magma compositions of shield volcanoes
low viscous
mafic magma chambers
Chemical weathering
water, oxygen, and other reactants chemically degrade the mineral components of bedrock
protolith for quartzite
quartz rich sandstone
what is relationship between cooling rate and igneous rock type
extrusive- faster cooling
intrusive- slower cooling
relationship between cooling rate and mineral crystal size (igneous)
faster cooling rate means smaller crystal size
slower cooling means larger crystal size
Oxidation
chemical reaction with oxygen causing rusting metallic iron
iron minerals bond with oxide minerals, exposed to Earth’s atmosphere
Vesicles- what does it indicate
pressure gas bubbles
magma is gassy- explosive
Slate-phyllite-schist-gneiss sequence
Sandstone
sand lithified to sandstone
coarse grains
wide variety of mineral grains
grain roundness varies
moderate to well sorted
Physical appearance of Flood Basalts
large igneous provinces
multiple explosive centers from fissured dikes
Low viscosity
lava spreaf out- higher temp and FEWER silica chains (mafic)
What does low vs high grade metamorphism indicate?
Low – finer grained crystals
High- coarser grained crystals
What are the differences between regional, contact, and subduction metamorphism?
Regional
Increasing temperature and Pressure
Heating AND deformation
Foliated
Range of depth
Contact
High temp, low Pressure
Heating NO deformation
Non-foliated
Shallow depth
Subduction
High Pressure low temp
Deformation NO heating
Dissolution
some minerals completely dissolve when reacting with water and natural acid
produce dissolved ions in water
followed by precipiation and often focused in fractures
As magma cools minerals crystallize out causing a change in the remaining magma composition. What is this process called?
Fractional crystallization
Metamorphic textures
foliation
lineation
non-foliated
schistosity
Which is NOT commonly associated with lava domes, stratovolcanoes, and calderas?
Mafic- Intermediate lava comp
Shield volcanoes have low slopes primarily because
the low viscosity of basaltic magma allows it to flow downhill for long distances.
How does fluids play a role in metamorphism
Interact chemically with minerals and cause new mienrals to replace existing ones
Hydrothermal metamorphic alteration
Can remove elements from rocks- seawater flows through fractures in fresh, hot basalt, reacting with and removing mineral ions
What does presence of coarser vs finer clast size indicate about energy of envionment and distance
coarser- high energy- small distance
finer- low energy- long distance
When material from a subducting slab reaches a certain depth, what gets released and added to the mantle above to cause the mantle to melt?
H2O
water
Inorganic Sedimentary Rock- Travertine
calcite slowly precipitate from water, leaving thin band/layer (caves and hot spring)
Intrusive igneous rocks
plutonic
magma solidifies BELOW the surgace
form various features called plutons
examples of chemical weathering
hydrolysis
Dissolution
Oxidation
Karst Topography
How does viscosity and gas influence eruption stlye
High gas- more explosive
High viscosity- stops more gas from escaping- more explosive pyroclastic
How are igneous rocks formed
cooling and solidification of magma/lava
as cools, minerals crystalize
What trend in clastic sedimentary rocks would you expect to see in Louisiana as time progressed from 100Ma to the present?
Coarsening of Sediment (clast size increase)
Batholiths
greater than 100 km2 igneous body; massive
hundred of miles long
form from multiple smaller plutons
associated with convergent plate boundaries
exposed by erosion
Continental Collision has what type of igneous rock comp
Felsic intermediate rock
felsic magma
Decompression Melting
lowering of Pressure WITHOUT changing the temperature of his rising mantle material
DIVERGENT boundaries (MOR, continental rifting)
HOTSPOTS
How does Metamorphism occur
Change in temperature and pressure and depth
Cause existing minerals to be unstable at new conditions
Results in growth of new stable mineral
Change in comp and or texture WITHOUT melting – igneous
chemical processes
Metamorphic
recrystallization
remobilization
pressure solution
protolith for greenschist
greenslate
Porphyitic texture and cooling rate
2 different cooling histories
one cools in magma chamber, then grows and gets to surface, erupts and rest of melt solidified
mostly extrusive
Lineation
Refer to elongated linear minerals (longer in one direction) that are aligned within a rock
NO orientation into planes
Breccia
coarse angular clasts
poorly sorted- large boulders to fine sediment
clasts of different rock types or all same type of rock
conglomerates
coarse clasts
rounder grains than breccia
poorly to moderately sorted
sand and/or mud matrix
Lineation Texture
Linear alignment of minerals within a rock.
Beach
Transitional
Important transport process- wave and tidal current
Main sediment- sand
Main rock- sandstone
Main strucute- plane bed, large cross beds
Constant wave activgity, little to no structure preserved
Main fossils- bioturbation, marine invertebrates, rare vertebrates, some corals
Which clastic sedimentary rock would be more likely deposited in a low energy environment?
mudstones or shales
Physical appearance of Cinder/Scoira cones
smallest volcanoes
conical, steep, symmetric sides
Silicate minerals in order of those first to last to crystallize
olivine
pyroxene
amphibole
biotite
K-feldspar
Muscovite
Quartz
Which of the metamorphic rocks listed does NOT have foliated texture?
Quartzite
Which of the following does NOT precede a volcanic eruption?
formation of pyroclastic flow
Flux melting
Addition of volatives allows rock to melt at lower temp
NO change in temp or pressure
SUBDUCTION ZONES
Continental Collision Meta Process
REGIONAL and FAULT metamorphism
Focused within THRUST shets (fold and thrust belt
SHEARING< folding and strongly FOLIARED Rocks, such as slates, schist, gneiss
SHEARING along deep faults
What causes initial magma composition to change
Partial Melting
Fractionantion
Assimilation
relationship between grain type, cooling rate, and type of rock
Coarse grained- slower cooling- intrusive
FIne Grained- faster cooling- extrusive
Continental Rift has what type of igneous rock comp
Felsic rock-
intermediate magma
Whan can precede a volcanic eruption
Seismic activity increases
increased gas activity
change in topography
change in temp
Stromatolites
Flat or hemispherically laminated structured of fine caebonate, fine organic matter, and clay/silt
Formed by trapping and binding of cyanobacteria
Formed today by mainly in shallow tidal zones
Oldest fossil
Occur in carbonate limestones
Viscosity
resistance to flow
Physical appearance of stratovolcanoes
distinct crater at top
rise high above landscape
snowcapped and steep symmetrical flanks
what gives igneous rocks coarse grained, phaneritic texture
When a magma cools slowly deep below the Earth’s surface,
WHy have flood basalts been a cause of extinction events
Release SO2- block sun from earth- cool- acid rain
Release CO2- global warming
long lasting eruptions
Deccan Trapps- 1/3; extinction of dinosaurs
Siberian Trapps- Great Dyinh- 95%
Chalk is considered a biochemical sedimentary rock because
It’s a carbonate that formed from the calcium-rich skeletons of microorganisms that had accumulated on the seafloor
What is used to classify igneous rocks
Texture and composition
what are three categories for depositional environemnts
Terrestrial (AKA Continental)- Diverse environments found on continents
Transitional (Marginal)- Shoreline/coastline environment zones of complex interactions between ocean and land
Marine- Completely, continuously under seawater
Types of Plutons
Igneous Dikes
Igneous Sills
Laccoliths
Stocks
Batholiths
Columnar joints
As magma melt cools and mafic silicate minerals crystallize out, the melt composition becomes
depleted in Fe, Mg, Ca and more abundant in Silica, Al, Na and K
Protolith for marble
limesotne
Remobilization
Various mienrasls in the rocks can partially melt than concentrate in areas of rocks-
producing light and dark bands
magma mixing
two different compositions of magma mix, final magma composition between the two
what are different types of sedimentary structures
Bedding planes
Laminatiosn
Graded Bedding
Bed Forms
Cross Beds
Bioturbation
Mudcracks and Raindrop impressions
Intermediate
Roughly equal amounts of light and dark mienrals
Diorite- intrusive
Andesite- extrusive
The collapse of crustal rock above a magma chamber following the emptying of that large magma chamber can result in the formation of?
formation of volcanic caldera
Schistosity is an example of which type of chemical or physical metamorphic process?
Rotation
Deformation of objects
Rounded grains become flattened in the direction of max stress
Degree of stretching increases
When a lava flow cools and forms a volcanic rock, it is considered to be
extrusive igneous rock
Organic sedimentary rocks
formed from organic material (plants) to procue coal, oil, and natural gas
Felsic rocks
MOST silica, LEAST Fe, MG
abundant light colored minerals- Quartz and Feldspar
Granite- intrusive
Rhylotite- Extrusive
Laminations
Parallel layers, less than 1 cm thick, fine grained sediments
Fine grained sediment deposited in QUIET,
LOW energy environment
Lake, deep ocean
Landslide
slop failure of steep, unstable slopes of volcano
explosive eruption, heavy rain, magma movement
STRATOVOLCANO or LAVA DOME
Hydrolysis
main proces breaking down silicate rock and create clay minerals
water and natural acids break down silicate minerals
produce dissolved ions in water and clay minerals
Mudstone (siltstone/claystone)
fine grained
silt lithified to silt
clay lithified to clay
Foliation
Refer to any planar metamorphic fabric where minerals are aligned/orientated to have lined up in planes
New minerals form
Common with abundant sheet silicate minerals
Slte, phyllite, schist, gneiss
why Hawaii volcanism mostly produces shield volcanoes, while Yellowstone volcanism has produced calderas from massive eruptions?
Yellowstone volcanism sits within continental crust resulting in more felsic-intermediate magma compositions and thus more explosive volcanic eruptions.
What are products of weathering of rocks
soil and smaller rock fragments
What are the metamorphic rock textures produced from directed stresses?
Shistosity- schist
Shearing- mylonite
Foliation- Gneiss
Ice/frost wedging
water in cracks freeze and expand, widening cracks
repeating cycles of freezing and melting pry rock apart
Regression
Drop of sea level and withdrawal of water from the land
Depositional environments shift seaward (go towards sea, ocean regressing)
Magma compositions of stratovolcanoes
high viscosity and silicate
felsic magma chamber
A sedimentary rock which contains environmental clues, such as well sorted sandstone with reddish coloring from oxidation and >1 meter (3ft) cross-beds, would mostly likely indicate which depositional environment?
aeolian
Extrusive igneous rocks
volcanic
magma erupts ABOVE earth’s surface as lava, melts, and solidifies above surface
lava flow and pyroclastic deposits
Physical appearance of shield volcano
long angles, broad flanks
small vents and craters at top
can be largest of volcano- size varies
Mechanical/Physical weathering
physical breakdown of bedrock into loose smaller particles (sediment)
How do geologists determine a regression or transgress occurred in the rock record of a stratigraphic section?
the Stacks of rocks- newer on top
recrystallization
Most common
Existing minerals recrystallize into laeger crystals
Or new mienrals growduring metamorphism
Shale to Schist- Quartz sandstone to Quartzine
Magma compositions of lava domes
high viscosity
highly fractured solified lava (intermediate-felsic)
Non-Foliation Texture
Metamorphic textures that do not have a directional component of its minerals
Mafic
Rich in Fe and Mg, poor in silica
Abundance of Ferromagnesian and K-Feldspar
Gabbro- intrusive
Basalt- extrusive
Karst Topography
thickness of limestone, dissolution create separate ind. spires
What are common volcanic features associated with mid-ocean ridges?
Lava flows on ocean floor forming pillow basalts
deep sea hydrothermal vents
Clastic sedimentary rocks are classified (dominantly) based on what?
grain size
Transform Boundaries
FAULT metamorphism- strike-slip faulting
Physical appearance of lava domes
dome feature- plugging of vent due to high viscosity
small to moderate in size
Shale
fissile mudstones, separated into thin sheets
Non-Foliated
Texture is granular and equi-dimensional (sugar)
NO alignment/orientation of minerals
NO new minerals form, usually composition of one kind of mineral
Quarts-rich sandstone- Quartzich
Interlocking Quartz cryals
Granual hard rocks
What is incorrect about intrusive igneous rocks
tend to have very small mineral crystals or glassy (no mineral crystals)
igneous sills
intrustion that runs parallel to layer
horizontal
Schistosity
Term for coarse grained, visible, platy minerals in a planar fabric, typical of schists.
Non-foliated metamorphic rocks form by which metamorphic process?
Recrystallization
Laccoliths
lens shaped, cause surface doming
What does the presence of a garnet or
Experienced much higher pressures and temperatures than chlorite
interplate and intraplate volcano
Interplate- Volcanism located at active plate boundaries like subduction zones, and divergent boundaries
Intraplate- Volcanism within a tectonic plate formed by hotspots
Biogenic Chert
Microcyralline quartz made of shells from microorganisms (plankton)
Siliceous ooze in deep ocean, lakes
when rocks are partially melted the resulting magma is always more waht
felsic and less mafic
Pophyritic
larger crystals with fine grained matrix
Stocks
less than 100 km2 igneous body; irregular shaped
Oceanic Subduction has what type of igneous rock comp
Ultramafic rock
mafic melt
Lithification
Process which loose sediments become solid rock (cementation and compaction)
Columnar Joints
way it cools; cracks form, cool outward to inward
Regional Meta
Alteration of rock by increase temp with high pressure (heating AND deformation)
Wide range in depths, temperature, and pressure
Distributed through wide geographic area
Caused by lagsacre geologic processes (mountain- compression)
Regional produced FOLIATED rocks
Bowen’s reaction series
** Illustrates the relationship of silicate minerals and temp **
Idealized model for crystallization of silicate minerals in a magmatic system
cementation
precipitation of minerals from water within pore spaces bind grain together
Pressure expansion
when rock makes way to surface from erosion and uplift,
pressure is dropped= expansion and cracking
Magma compositions of Cinder/Scoira cones
low viscous lava
mafic lava with high volatiles (gassy)
Inorganic
evaporates/precipitates from water (by chemical reactions)
Classified by composition
Which type of magma is typically silica-rich felsic or intermediate in composition and produce granites, rhyolites, tuffs, and andesites?
High Viscosity Magma
What are the two processes of lithification
cementation
compaction
Mudcracks and raindrop impressions
When wet-logged clay rich sediment dries out
Shrinking mud forms cracks- get preserved if sediment fills in cracks
Can form TIDAL FLATS; DRIED LAKES: SHORELINES
Aeolian
Continental - Wind-blown
Sand dragged along surface or briefly lifted- silt and clay blown away and carried long distances
Main sediment- very well sorted sant and silt
Main rock- sandstone
Main strucute- large cross beds
Main fossils- rare
Chalk
Soft powdery, brittle limestone, Composed mostly of calcite
Accumulation of calcium- rich shells of microorganisms and algae in deep ocean
MOR metamorphic process
NORMAL faulting, down-dropped fault blocks
CONTACT metamorphism and HYDROTHERMAL chemical alteration
Deep Marine
Relatively flat plain, low energy
Dominated by ocean currents
Main sediment0 very fine grains mud and oozes
Rocks: chert, shale, carbonate, mudstone
Difference between confining pressure and directed stress?
Confining
Same amount of stress from all direction
Uniformly distributed- all rocks
Directed
Different amounts of stress from different direction
Unequal distribution
Modifies the parent rock at mechanical level, crates identifying textures- change arrangement, size, or shape of crysalts
Diagenesis
As sediments are buried, temps and pressure increase and will cause a low temp/loq pressure alteration
Heat and pressure chemically alter sediments
Pore space between grains can reduce or increase
why volcanoes associated with subduction zones tend to be explosive.
they are generally more viscous and effectively retain gases
Order of Sedimentary rock process in rock cycle
Weathering (mechanical and chemical)
erosion, transport, deposition
Burial
lithification, diagenesis
Bed Forms
Sedimentary structures formed from a current (water or wind) working on sandy sediment
Ripples
Dunes
What metamorphism occurs along continental collision settings? (choose all that apply)
regional metamorphism focued within thrust sheets
Ripples
Small ridges in the sands creates as sand piles up
Cm scale bedforms
Asymmetrical- unidirectional flow- rivers
Symmetrical- Bidirectional flow- waves, tides
Why does regional metamorphism and fault metamorphism produce foliated, lineated textures?
lots of pressure
Physical appearance of Calderas
moderate to very large circular, steep-walled depressions
Salt Expansion
evaporation causes salt to precipitate out of solution and grow and expand into cracks in rock
two different types of igneous rocks
intrusive and extrusive
High Viscosity
lava plies out- lower temp and MORE silica chains (felsic)
peat
partially decayed vegetation or organic matter converted into carbon-rich coal under high temp and pressure
How are volcanoes monitored
seismic activity
gas activity
look for deformation
measure ground temp
past historical eruption
Shallow Marine
Continental shelf- Marine
Moderate energy, storms
Important transport process- waves and tidal current s
Main sediment- fine sand and mud
Main rock- mudstone, sandstone, carbonates
Structures- planar bedding, cross beds, storm influence
Main fossils- bioturbation, few marine invertebrates, fish
Continental Rifts Meta process
NORMAL faulting, down dropped fault nlocks
CONTACT metamorphism; SHEARING along deep faults, HYDROTHERMAL chemical alteration; BURIAL metamorphism
Protolith
The rocks that existed before the changes that lead to a metamorphic rock
Magma composition (amount of silica) and temperature controls which of the following?
magma viscosity
What is the difference between a lahar and pyroclastic flow?
Lahars involves water and pyroclastic debris, while pyroclastic flows involve very hot gasses and pyroclastic debris, both flow down the flanks of the volcano.
Bowen’s Reaction Series
The concept that describes the crystallization order of silicate minerals in melt related to temperature
Fluvial
Continental- Rivers
High low energy, water transport
Meandering and braided rivers
Meandering- 1 single channel
Braided- multiple channels
Main sediments- sand, mud, coarse grains
Main rocks- sandstone, conglomerates, siltstone
Main structure- cross beds, asymmetric ripples, channels
Main fossils- bone beds,
Cross-Beds
How do ripples and Dunes Migrate
Wind or water transport grains on upstream side and deposits grains on downstream side
Migrating dune/ripple erodes, the crest in front of it , leaving base as layer behind with crossbedding
Downstream migration of ripples produce crossbedding
Paleocurrent direction
Crossbeds tilt down- current and thus indicate DIRECTION OF FLOW
Lahars
slurry resembling wet concrete
consist of water, ash, rock fragments, other debris
Triggered by fast melting snow and glaciers
STRATOVOLCANO
examples of mechanical weathering
pressure expansion
ice/frosh wedging
salt expansion
biological activity
Which type of metamorphism occurs at a relatively low temperature and high pressure environment, and the diagnostic metamorphic rock is blueschist.
subduction zone meta
Index Mineral
Minerals that form at a specific range of temperatures and pressures. Using a collection of index minerals narrows down the conditions of rock formation
Subduction Zone
Unique: High pressure, low tempes
Slabs slow to increase in temp at depth, pressure larger affedct
Mafic oceanic lithosphere subducted and meta
Greenston, greenschist, blueschist, eclogice
what gives igneous rocks glassy texture
When a melt cools instantly
Tsunamis
Displace of large volume of water can produce a tsunami-
wide reaching impact
Subduction Zone
Convergence
SUBDUCTION and REGIONAL metamorphism
Reverse/Thrust Faulting
FAULT metamorphism and BURIAL metamorphism
CONTACT metamorphism- magma intrusion into continental crust
what are plutons
featured created by intrusive igneous rocks
Mantle Plume
RIsing Material and heat derived from mantle
MOR has what type of igneous rock comp
ultramafic rock-
mafic magma or intermediate felsic rock/melt
5 different types of metamorphism
Contact
Regional
Subduction Zone
Burial
Fault
