Geology Exam 2
Give an example of a place currently undergoing continental rifting.
East african rift
What kind of a melting do you expect at a subduction zone?
Flux-induced melting
Dikes and sills are
High-angle and low-angle igneous intrusions
what is the primary factor that keeps the mantle rocks melting at very high temp of ~3000 C
Overburden pressure
Metamorphic grade implies
P, T conditions of a rock environment
Metamorphism implies
P, T, Stress, Fluids, conditions of a rock environment
Burial metamorphism is common in
Sedimentary basin
Bowen's Reaction Series
Shows that minerals in a cooling magma crystallize, in a predictable order
Which is the correct sequence for increasing grain size inside the Earth?
Slate, phyllite, schist, and gneiss
Which is the correct sequence for increasing metamorphic grade inside the Earth?
Slate, phyllite, schist, and gneiss
Regional metamorphism is typical of
mountain belt
How would you get a metamorphic rock from an igneous rock
reheating
What is the dominant mineral composition of marble
Calcite
Given an example of LIP in continental US
Columbia River Flood Basalt
Vesicle in vesicular textures are remnants of
Volatile passages in an igneous rock
The rock type produced by contact metamorphism is called
hornfels
A metamorphic rock contains the minerals coesite and diamond. what can you infer about the P/T conditions of the rock?
very high pressure
Which of the following is a possible metamorphic temperature?
450 C
Which of the following situations are impossible in nature?
A granite rock olivine and a metamorphic rock with marine shell fragments
Which of the following rocks would you expect to react with acid? A. Micrite B. Fossiliferous limestone C. Chalk D. All of them
All of them
Extrusive, igneous rock texture can be
Aphanitic or glassy fragmental texture
Which of the following words may be used to describe portions of rocks with for porphyritic texture
Aphantic, phenocrysts, groundmass
Which of the following melt compositions do you expect to travel long distances?
Basalt melts
What would you call a rock that has purple size angler clasts
Breccia
Two magma chambers of similar size are undergoing crystallization. Chamber A is tubular. Chamber B is spherical which chamber cools faster
Chamber A
All phaneritic textures are:
Coarse-grained, derived from magma, and cooled slowly
List three tectonic and or mental processes that trigger decompression melting
Continental rifting, sea floor spreading, mantle plume
mafic igneous rocks tend to have color shades
Dark
Graphite in a metamorphic rock is stable up to a certain P/T condition. Imagine metamorphic rock containing graphite is subjected to more intense P/T conditions, such that the graphite becomes unstable at the new P/T conditions. What will be the resulting new mineral phase?
Diamond
Which of the following tectonic processes cools rock inside the Earth?
Exhumation
pyroclastic flow occurs in
Felsic melt flows Extrusive settings
All aphantic textures are
Fine-grained, derived from lava, called faster
The characteristics mineral for subductions zone metamorphism which imparts a blue hue to the subduction zone metamorphic rock is
Glaucophane
Which of the following rocks contain banded foliations?
Gneiss, Migmatite
Porphyritic rocks are named for the size of
Ground mass grains
Given an example of a location experience hotspot, it is volcanism
Hawaii
With increasing pressure, inside the Earth:
High density mineral are formed
Intra-plate volcanism is seen at
Hotspots
A dike intrudes into:
Igneous, sedimentary, and metamorphic rocks
A porphyritic texture is one in which
Individual crystals are a mix of coarse and fine-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 indicated
Initial slow cooling, and then fast cooling
A metaphoric rock specimen contains the minerals Muscovite and biotite but no chlorite. What cna you infer about the P/T conditions where the rock formed?
Intermediate P/T
Flood basalts are characteristics of
Large igneous province
LIP
Large igneous province
Hot rock melts on the earths surface is called
Lava
Felsic igneous rocks tend to have. color shades
Light
Hot rock melts inside the Earth is called
Magma
What kind of igneous rocks do you expect at mid-ocean ridges
Mafic fine-grained
Composition of the earths mantle is
Mafic to Ultramafic
Which of the following is a mixed rock?
Migmatite
Which of the following rocks have banded foliations?
Migmatite
During metamorphism in a compressive stress field, how does the minerals acquire preferred orientation?
Mineral long axes align normal to the direction of maximum compressive stress
During metamorphism recrystallization, there is a change in:
Minerals composition of the protolith and texture
How does molten rock move upwards through the earths mantle?
Molten rock is less dense than the surrounding solid rocks
Which of the following rocks displays a stunning, black, glassy texture
Obsidian
Which of the following minerals crystallizes via the discontinuous reaction series?
Olivine, pyroxene, and amphibole
Coarse green crystals in for porphyritic texture are called
Phenocrysts
A vesicular texture is one in which
Pores are abundant
Another name for fragmental texture is
Pyroclastic texture
When a sandstone is metamorphosed, it turns to:
Quartzite
Which if the following metamorphic rocks are coarse-grained?
Quartzite, gneiss, schist
How would you get a gneiss from phyllite?
Reheating
Which of the following metamorphic rocks have visible mineral grains?
Schist
Which of the following rocks may be a protolith of gneiss?
Schist, shale, and granite
Which of the following minerals is found in the impact craters only?
Stishovite
Listing for tectonics settings, where igneous activity occurs
Subduction zones, mid ocean ridges, continental rifts, hotspots
formation of migmatite is an indication of:
The rock has just entered the zone of melting the Earth
Shock metamorphism is associated with
Ultrahigh P/ high T
Which of the rocks is not derived from an igneous rock melt
Tuff
Which of the following melt compositions are arranged in the order of increasing volcanic explosivity
Ultramafic < mafic < indeterminate < Felsic
Which of the following melt compositions are arranged in the order of increasing velocity
Ultramafic < mafic< intermediate < Felsic
An English rock contains less than 45% SiO2 is called
Ultramafic rock
Fragmental texture is formed from
Volcano, ash, and volcanic rock debris
And a flux induced melting, which of the following can act as a flux
Water vapor, carbon dioxide, sulphuric dioxide
I'm magma that is rich in volatiles is called
Wet magma
which of the following pairs of minerals are part of the continuous reaction series in the Bowen's reaction series
ca rich plagioclase and na rich plagioclase
A low grade metamorphic rock containing chlorite biotite muscovite is subjected to higher P/T conditions. Which of the following minerals will be replaced first during Neo crystallization?
chlorite
Which of the following processes can turn a sedimentary rock into a metamorphic rock
contact metamorphism, subduction metamorphism, and burial metamorphism
What kind of melting do you expect in a continental rift tectonic setting?
decompression melting
What kind of melting do you expect just under a mid-ocean ridge
decompression melting
quartzite and marble lack foilation because they have
equant mineral grains
a course-grained magmatic igneous rock with 65% SiO2 and containing minerals like quartz, K-feldspar may be called
granitie
Chemical alteration of ocean floor basalts is an example of
hydrothermal metamorphism
Felsic magma
is more viscous than mafic magma.
What is the parent rock for marble
limestone
How would you get an igneous rock from another igneous rock
melting
All intrusive igneous rocks have
phaneritic texture
In most types of metamorphism, bulk element composition of a parent rock is:
same as that of the parent rock
How would you get a conglomerate from a granite?
weathering
