Igneous Rocks
Ternary
A triangular graph in which the relative proportions of three minerals is used to classify a rock is called a __ diagram.
Vesicles
Basalt in the tops of subaerial lava flows and cinder cones commonly contains lots of:
Air
Basalt which erupts into this medium forms scoria, breccia and lava flows:
Gabbro
Beneath the basalt of the oceanic crust is a layer of what rock type?
Olivine
The first mineral to crystallize out of a melt:
Bowens Reaction Series
The order that minerals crystallize out of a melt:
Volcanic
Extrusive:
Ultramafic
Igneous rock, with more than 90% of dark minerals (mostly olivine), are referred to as:
95%
Igneous rocks make up about __ of the Earth's crust.
Meteorites
Impacts by __ during accretion of the Earth led to extensive melting.
Pegmatite
In some locations extremely course-grained __ masses with beautiful crystals occur with granite.
Divergent Boundaries
In what plate tectonic boundary settings is 3/4 of all extrusive rock produced?
Diorite
Large intrusions in the Andes Mountains are likely what rock type?
Quartz
The last element to crystallize as a magma cools:
Incompatible Elements
The last parts of a melt to crystallize as a magma cools:
Columns
During the cooling of a thick lava flow, contractional fractures form to create basalt:
Basalt
The lava flows of the Deccan Traps in India, the Siberian Traps in Russia, and the Columbia River Plateau of Washington are what rock type?
Silicon, Oxygen, Aluminum, Sodium, Potassium, Calcium, Iron, and Magnesium
The magma from which the minerals crystallize is rich in what eight elements?
Basalt
The most common extrusive volcanic rock:
Andesite
This lava is intermediate between felsic and mafic in composition and quite viscous:
Calcium Rich
This plagioclase composition is the first to crystallize out of a cooling melt?
Viscosity
This property of magma which governs its flow is determined by temperature, composition, and crystal content:
Pyroclastic
This term describes the texture of volcanic airfall rocks like tuffs:
Porphyritic
This texture involves visible crystals within a fine grained matrix:
Igneous Rocks
This type of rock is formed when molten magma cools:
Rhyolite, Andesite, and Basalt
Three types of lava:
Pyroclasts
Volcanic bombs, lapilli and volcanic ash are all called:
Subduction
Water is driven out of the oceanic lithosphere in __ zones, and it causes melting in the overlying mantle.
Diorite
A grey intermediate intrusive igneous rock:
Plutonic
Intrusive:
Conchoidal
Obsidian is easy to sharpen because it breaks with a __ fracture.
Gabbro
A dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt:
Melt
A decrease in pressure, an addition of water, an increase in temperature. Any of these can __ rock.
Batholith, Stock
A large irregular intrusion is a __, whereas a smaller irregular discordant is a __.
Melt
Decrease the pressure, add some water, increase the temperature. These are three ways that can result in this phenomenon:
Dike, Sill
A tubular discordant body is a __, whereas a relatively thin tubular concordant body intruded along bedding planes is a __.
Pumice
A volcanic rock that is a solidified glassy foam that floats:
Volcanic
An extrusive igneous rock can also be called:
Plutonic
An intrusive igneous rock can also be called:
Greenstones
Ancient lava flows, often altered to minerals like chlorite, are known as:
Fractional Crystallization
As magma cools, minerals typically crystallize from the melt at different temperatures. This is called:
Dark
Despite its felsic composition, obsidian is __ in color.
Vesicles
Beautifully crystallized species of zeolites, opal, quartz or calcite are frequently found in basalt:
Countertop
Because of its durability, granite has become a popular kitchen __ in modern houses.
Basalt
Ca-Plag, pyroxene and olivine form this type of lava:
Radon
Cellars sunk into soils formed over uraniferous granites can become a trap for __ gas.
Peridotite
Course-grained ultramafic rock:
Midocean Ridges
Decompression melting creates the ocean crust at what plate boundaries?
Pressure
Decompression melting occurs because of a decrease in __ as solid rock rises toward the surface.
Rhyolite
Felsic lava:
Light, Low
Felsic rocks are usually __ colored, and have a __ density.
Obsidian
Felsic volcanic glass:
Texture
Fine grained vs. course grained is an igneous rock classification based on:
Thin Sections
Generally, the mineral constituents of fine-grained extrusive igneous rocks can only be viewed in:
Phaneritic and Aphanitic
Geology jargon for course and fine grained respectively:
Phaneritic
Geology word for course-grained:
Porphyritic
Geology word for courser-grains in a finer-grained matrix:
Aphanitic
Geology word for fine-grained:
Magma
Geology word for melted rock:
Construction Stone
Granite is nearly always massive, hard and tough, and therefore it has gained widespread use as a:
Continental
Granitic rock is widely distributed throughout which type of crust on Earth?
Concordant, Discordant
If the intrusion is parallel to the country rock, the body is__. While if it cuts across the country rock, it is __.
Granite, Diorite, Gabbro, Peridotite
List four intrusive rocks ranging in order, from felsic to ultramafic:
Rhyolite, Andesite, Basalt
List three extrusive rocks ranging in order, from felsic to mafic:
Dark, High
Mafic rocks are usually __ colored, and have a __ density.
Partial Melting
Magma can be derived from preexisting rocks by this process:
Coarse
Magma cools slowly at depth, and as a result, intrusive igneous rocks are:
Lava
Magma extruded onto the surface either beneath water or air:
Lava
Magma extruded onto the surface is called:
Magmas
Most __ are mixes of melt and crystals, and gas bubbles.
Yellowstone
Most obsidian in archaeological sites in our region probably originated in:
Igneous Rock
Most radiometric dating is done on this general type of rock:
Granite
Name a common and widely occurring type of intrusive, felsic, igneous rock:
Amorphous
Obsidian is not a mineral because it is:
Tephra
Particles falling from the eruption clouds form layers of ash on the ground technically called:
Obsidian
Perhaps the sharpest known natural material:
Diorite
Phaneritic equivalent of andesite:
Gabbro
Phaneritic equivalent of basalt:
Granite
Phaneritic equivalent of rhyolite:
Mode of Occurrance
Plutonic vs. Volcanic is an igneous rock classification based on:
Tuffs
Pyroclastic deposits which have been lithified:
Volcanic
Pyroclastic rocks are clastic rocks composed of __ materials.
Granite
The central cores of major mountain ranges consist of intrusive igneous rocks, usually:
Emplacement
Stoping, assimilation, and forceful injection are three mechanisms that might explain the:
Solidus (Melting Point)
Temperatures can exceed the __ __ __ of a crustal rock due to compression at a plate boundary.
Continents, Oceans
The Earth's crust is about 35km thick under the __, but is only some 7-10km beneath the __.
AA, Pahoehoe
The __ form of lava flow is rough; the __ form of lava is smooth and ropey.
Bowens
The reaction series is important for understanding the idealized sequence of fractional crystallization of a magma:
Particle Size and Mineral Composition
The two most important variables used for the classification of igneous rocks. What are:
Quartz
The very last mineral to crystallize from a melt:
Rhyolite
The volcanic equivalent of plutonic granite is:
Pillows
These are very common in underwater basaltic flows and are diagnostic of an underwater eruption:
Intrusive
These igneous rocks are formed from magma that cools and solidifies within the earth:
Decompression
This cause of melting is responsible for mid-ocean ridges and ocean islands such as Hawaii:
Temperature Increase
This cause of melting is responsible for rhyolitic magmas in continental crust in collision zones such as the Himalayas:
Water
This cause of melting is responsible for the rise of andesitic magmas above subduction zones:
Pumice
This forms the grit in Lava Soap:
Magma
This is most commonly a mixture of melt, crystals, and gas bubbles:
Andesite
This lava is characteristic of subduction tectonic environments in active oceanic margins, such as the western coast of South America:
Igneous Rocks
What we do know about the composition of the mantle is derived from what general type of rocks?