TEST 2 GEOL
What kind of melting is expected at subduction zones?
Flux-induced melting
What rocks have banded foliations?
Gneiss and Migmatite
Give an example of a place currently undergoing continental rifting:
East African Rift
With increasing P, inside the earth:
High density minerals are formed
Dikes and sills are
High-angle, low-angle igneous intrusions
What does sorting of a clastic sedimentary rock indicate?
Number of sources involved
What is the primary factor that keeps the mantle rocks from melting at very high temperatures of 3000 C?
Overburden pressure
Metamorphic grade implies
P, T Conditions of a rock environment
Metamorphism implies
P, T, Stress, Fluid conditions of a rock environment
what rock displays glassy black textures
obsidian
What is a chemical sedimentary rock?
Oolitic Limestone
Burial metamorphism is common in
Sedimentary basins
The Grand Canyon has what type of rocks exposed?
Sedimentary, Igneous and metamorphic rocks
What would you call a very fine clastic grained sedimentary rock with clay minerals?
Shale
T/F: A conglomerate can contain volcanic glass
T
T/F: Sedimentary formations are arranged in layers
T
T/F: Sedimentary formulations are mappable
T
T/F: Sedimentary formulations may contain sedimentary structures
T
Does tabular or spherical chambers cool faster
Tabular
What does red shale tell us about its depositional environment?
The enviro of deposition was exposed to atmosphere
The original, unmetamorphosed rock from which a given metamorphic rock is formed (parent rock)
protolith
another name for fragmental texture is
pyroclastic texture
What minerals are part of Bowen's Reaction Series?
Ca- and Na- rich plagioclase
What is the dominant mineral composition of marble?
Calcite
What is the dominant mineral in limestone?
Calcite
Give an example of LIP in continental US:
Columbia River Flood Basalts
Vesicles in vesicular textures are remnants of
Volatile passages in an igneous rock
The rock type produced by contact metamorphism is called
hornfels
Match: Volcano tops
High T/Low P metamorphism
fragmental texture is formed from
Volcanic ash and rock debris
What is a temperature adequate for Metamorphism?
200-700 F
Alternating red and black shales in a sedimentary sequence indicate that the deposition environment experienced:
A rise and fall of sea level
What is a biochemical sedimentary rock?
Chalk
What words may be used t describe portions of rock with porphyritic texture
Aphanitic, Phenocrysts, Groundmass
Cross beds indicate
Average flow direction
Where would you expect a chemical sedimentary rock like salt to be deposited?
Beaches
What would you call a rock that has pebble-size angular clasts?
Breccia
What sequence represents a correct sequence of deposition away from source?
Breccia-Conglomerate-Sandstone-Shale
Lithification involves:
Burial, Compaction & Cementation
in a flux-inducing melt, what can act as flux
CO2, H2O, SO2
Alluvial fan is a type of depositional environment where the following happens:
Changes in riverflow velocity, change in slope of the land, deposition of sediments eroded from mountain tops
A low-grade metamorphic rock containing chlorite-biotite-muscovite is subjected to higher P/T conditions> Which mineral will be replaced first during neocrystallization?
Chlorite
All phaneritic textures are
Coarse-grained, derived from magma, and cooled slowly
What is process that can turn a sedimentary rock into a metamorphic rock?
Contact, Subduction, Burial - metamorphism
List 3 tectonic and/or mantle processes that trigger decompression melting
Continental rifting, sea floor spreading, mantle plume
What rock is made entirely of marine organisms?
Coquina
Ripple marks on sandstone indicate
Current flow conditions
What kind of melting is expected at mid-ocean ridges?
Decompression melting
What kind of melting is expected in a continental rift tectonic setting?
Decompression melting
Graphite after new P/T conditions that causes it to become unstable and convert into a new phase:
Diamond
Match: Mylonites
Dynamic metamorphism
Quartzite and marble lack foliation why?
Equant mineral grains
What process cools rocks inside the Earth?
Exhumation
T/F: A granite can contain olivine
F
T/F: A metamorphic rock can contain shell fragments
F
Pyroclastic flow occurs in:
Felsic melt flows and Extrusive settings
All aphanitic textures are
Fine-grained, derived from lava, and cool faster
Principle of uniformitarianism states that:
Geologic processes occurring now, happen throughout Earth's history
The characteristic mineral for subduction zone metamorphism which imparts blue hue to the subduction zone metamorphic rocks is:
Glaucophane
During metamorphic crystallization, there is a change in:
Grain size of the protolith minerals and the texture
A coarse grained magmatic igneous rock with 65% SiO2 and containing minerals like quartz, K-feldspar may be called:
Granite
Porphyritic rocks are named for the size of
Groundmass grains
Match: Deeper parts of subduction zones
High P/High T metamorphism
Chemical alteration of ocean floor basalts is an example of
Hydrothermal metamorphism
A dike intrudes into
Igne, Sedi, Meta rocks
A metamorphic rock-specimen contains the minerals muscovite and biotite but no chlorite, what can you infer about the P/T conditions where the rock was formed?
Intermediate P/T
Felsic magma:
Is more viscous than mafic magma
Flood basalts are characteristic of
LIPs
LIP is
Large Igneous Provinces
Hot rock melt outside the earth:
Lava
The dominant rock type in coral reefs is:
Limestone
What is the parent rock of marble?
Limestone
Hot rock melt inside the earth:
Magma
Match: Accretionary Prism
Low T/High P metamorphism
What kind of igneous rocks do you expect at mid-ocean ridges?
Mafic fine-grained
Composition of the earths mantle is
Mafic to Ultramafic
How would you get an igneous rock from an igneous rock?
Melting
What rock would react with acid?
Micrite, Limestone, Chalk
What is an example of a rock with banded foliations?
Migmatite
Which is a mixed rock (meta-igne)
Migmatite
During metamorphism in a compressive stress field, how does the mineral acquire preferred orientation?
Mineral long axes aligns normal/perpendicular to the direction of maximum compressive stress
Why does molten rock move upward through the Earth's mantle?
Molten rock is less dense than the surrounding solid rocks
Regional metamorphism is typical of
Mountain belts
A small stream in an arid region which is experiencing severe droughts for a few years continuously is expected to best preserve the following sedimentary structures:
Mudcracks
What minerals crystallize via the discontinuous reaction series
Olivine, Pyroxene, amphibole
What is the dominant mineral in sandstone?
Quartz
When sandstone is metamorphosed, it turns to:
Quartzite
What is a metamorphic rock that is coarse-grained?
Quartzite, Gneiss, Schist
What does black shale tell about its depositional environment
Reducing marine conditions
How would you get a metamorphic rock from an igneous rock?
Reheating
What is a rock with visible mineral grains?
Schist
What is a protolith of Gneiss?
Schists, Shale, Granite
What is the sequence of increasing grain size inside Earth: Schist, Slate, Phyllite, Gneiss?
Slate-phyllite-schist-gneiss
What is the sequence of increasing metamorphic grade inside Earth: Schist, Slate, Phyllite, Gneiss?
Slate-phyllite-schist-gneiss
What is a mineral found in impact craters only?
Stishovite
List 4 tectonic settings where igneous activity occurs
Subductions, Midocean ridges, continental rifts, hotspots
Where would you expect coal to be deposited?
Swamps
Sediments eroded from Putnam County by the Caney Fork River may be deposited in:
The gulf of mexico
Shock metamorphism is associated with:
Ultrahigh P/High T
Formation of migmatite is and indication of:
The rock has just entered the zone of melting in the Earth
what rock is not derived from an igneous rock ment?
Tuff
What is the correct order of melt compositions arranged in order of increasing viscosity
Ultramafic < Mafic < Intermediate < Felsic
What is the correct order of melt compositions arranged in order of increasing volcanic explosivity
Ultramafic < Mafic < Intermediate < Felsic
An igneous rock containing <45% SiO2 is called
Ultramafic Rock
A metamorphic rock contains the minerals coesite and diamond
Very high P conditions
How would you get a conglomerate from granite?
Weathering
Correct order of clastic rock formation: Erosion, Weathering, Deposition, Burial, Compaction, Cementation
Weathering-Erosion-Deposition-Burial-Compaction-Cementation
Does depth inside earth correlate to slower cooling (the deeper the slower)
Yes
Extrusive igneous rock textures can be:
aphanitic or glassy or fragmental in texture
Mafic igneous rocks tend to have _____ color shades
dark
an example of a hotspot induced volcanism
hawaii
intra-plate volcanism is seen at:
hotspots
a porphyritic texture is one in which
individual crystals are a mix of fine and coarse grained crystals
A phaneritic texture is one in which
individual crystals can be seen with the naked eye
An aphanitic texture is one in which
individual crystals cannot be seen with the naked eye
porphyritic textures indicate
initial slow cooling then fast cooling
Felsic igneous rocks tend to have _____ color shades
light
All intrusive igneous rocks have
phaneritic texture
coarse-grained crystals in porphyritic textures are called
phenocrysts
Vesicular texture is one in which
pores are abundant
In most types of metamorphism, bulk element composition of a parent rock is:
same as that of the parent rock
Bowen's Reaction Series
shows that minerals in a cooling magma crystallize in a predictable order.
Magma that is rich in volatiles is called
wet magma