Geology
Due to old oceanic crust being recycled at subduction zones, all oceanic crust is less than _____
200 MA
Minerals are divided into mineral classes based on anionic groups. Carbonates, such as calcite (CaCo3), display _______ directions of cleavage where the cleavage planes are _____ to one another.
3; Inclined
The age of the earth is approximately ______
4.54GA
Phyllite (Metamorphic)
A fine-grained metamorphic rock with a well-developed laminar structure, and is intermediate between slate and schist rocks. Crinkled or wavy appearance.
Batholith
A mass of rock formed when a large body of magma cools inside the crust
Laccolith
A massive igneous body intruded between preexisting strata
cinder cone
A steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening
Dikes
A structure built to prevent ocean waters from flooding adjacent land
glassy texture
A term used to describe the texture of certain igneous rocks, such as obsidian, that contain no crystals.
gneissic texture
A texture of metamorphic rocks in which dark and light silicate minerals are separated, giving the rock a banded appearance.
plate tectonics
A theory stating that the earth's surface is broken into plates that move.
slate
A type of Metamorphic rock that was once shale rock formed by heat and pressure.
slaty cleavage
A type of foliation that is characteristic of slates, in which there is a parallel arrangement of fine-grained metamorphic minerals.
dormant volcano
A volcano that has not erupted for a long time, but may erupt again one day.
extinct volcano
A volcano that has not erupted for thousands of years and probably will not erupt again.
alluvial fan
A wide, sloping deposit of sediment formed where a stream leaves a mountain range
flux melting
AKA Volatile-Driven Melting: Melting aided by the addition of water or other fluid -the addition of water to the already hot mantle rocks lowers their melting temperature resulting in partial melting of ultramafic mantle rocks to yield mafic magma.
hot spot
An area where magma from deep within the mantle melts through the crust above it
Foliation
An arrangement of minerals in flat or wavy parallel bands.
effusive eruption
An eruption that yields mostly lava, not ash.
Igneous rock has a different name depending on whether the rock is intrusive or extrusive, an intermediate composition igneous rock is called a ____ if extrusive and ____ if intrusive.
Andesite; Diorite
The distance a volcanic arc occurs from the trench is determined by the _____ of the down going lithospheric plate.
Angle
physical weathering
Any process that breaks rock down into smaller pieces without changing the chemistry of the rock; typically wind and water.
volcaniclastic debris
Ash, cinders, and blocks are all types of ____________.
Magmas can be modified in a number of ways, what is the process called where a magma body incorporates surronding country rock?
Assimilation
The lithosphere floats on a plastic layer called the ______ that flows very slowly at temperatures > 1,280 C
Asthenosphere
graded bedding
Bedding in which the particle sizes become progressively heavier and coarser toward the bottom layers
______ states that all matter and energy was packed into an infitesimally small point which exploded _____ years ago.
Big Bang Theory, 13.8 GA
The heated, mineral-laden water then circulates back out of the crust, which causes minerals to precipitate forming what feature?
Black Smokers
A turbidity current is the rapid downslope movement of a mizture of sediment and water which is denser than the surronding clear water producing a graded deposit with coarser grains at the _____ with finer grains at the _____
Bottom;Top
When a critical volume of magma have been evacuated from a magma chamber during an eruption, a collapse feature called a _____ is formed
Caldera
grain sizes
Clay, Silt, Sand, Gravel/Pebble, Cobble, Boulder
If a mineral breaks to form distinct planar surfaces that have specific orientation in relation to the crystal lattice, then the mineral exhibits _________
Cleavage
As a basaltic lava flow cools, the rock contracts due to heat loss, which may cause the rock to frature into a polygonal pattern called ____
Columnar Jointing
The viscosity of lava is primarily determined by it's ____, which in addition to _____ control the explosivity of an erruption.
Composition; volatiles
Conglomerate
Conglomerate is a coarse-grained clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts, e.g., granules, pebbles, cobbles, and boulders, larger than 2 mm in diameter.
What type of metamorphism develops in response to heat without change in pressure or differential stress, typically due to an igneous intrustion, and would the metamorphic rock produced be foliated or non foliated?
Contact Metamorphism, Nonfoliated
_____ boundaries are marked by deep-ocean trenches and volcanic arcs where oceanic lithosphere subducts beneath an overriding plate
Convergent
Continental collision occurs at _____ when a buoyant piece of crust or an island arc moves into the subduction zone, causing the continetal crust to become _________ during collison.
Convergent Boundaries, Thicker
Lamination
Covering the surface of a material with a thin sheet of another material typically for protection, preservation or aesthetic reasons.
Sedimentary rock structures and textures
Cross Bedding and Ripple Marks, Dunes, Scour Marks, Tool casts, fossils, mud cracks, lamination, layering, stratification
What is the process called which modifies the composition of magma by mafic minerals crystallizing first and settling out of a magma body (therefor not reacting with it), enriching the liquid component of the magma in silica?
Crystal Fractionation
The _____ of a mineral referes to the shape of a single crystal with well-formed crystals faces.
Crystal Habit
Obsidian is often a black volcanic glass that has a similar chemical composition to the mineral quartz (SiO2). What feature does quartz have that obsidian does not that prevents it from being classified as a mineral?
Crystalline Lattice
What is the process called where hot mantle rock undergoes a decrease in pressure, commonly near mid-ocean ridges, causing a melt to form?
Decompression Melting
What process is responsible for gerenating a melt and the formation of new crust at Mid-ocean Ridges?
Decompression Melting
A _____ is a wedge of sediment that accumulates where moving water enters standing water and deposits sediment load, composed of gravely topset sandy foreset and silly bottomset beds.
Delta
cross bedding
Depositional feature of sedimentary rock that forms as inclined layers of sediment are carried forward across a horizontal surface
scour marks
Depressions or erosional features formed as a current flows across a bed of sand.
Which process caused the internal stratification of Earth into different layers, where heavier elements formed the core and mantle, while lighter elements formed the crust?
Differentiation
Eruptive Styles of Volcanoes
Effusive vs. Explosive Volatiles Viscosity Silica Content
If a mineral displays well-formed crystal faces then it is often described as a ____ crystal.
Euhedral
eustatic sea level
Eustatic (global) sea level refers to the sea level change of the volume of Earth's oceans. This is not a physical level but instead represents the sea level if all of the water in the oceans were contained in a single basin.
As the viscosity of a magma/ lava is increased, the resulting eruption is more likely to be ____
Explosive
At convergent plate boundaries, such as the Cascadia Subduction zone, an arc is formed where ____ eruptive styles are expected due to the ____ composition of magamas that are generated.
Explosive; silica-rich
Viscosity, or resistance to flow, depends on temperature, volatile content, and silica content. Based upon this information, which magma type would be the most viscous?
Felsic
What magmas are characterized by having the lowest concentration of iron (Fe) and magnesium (Mg) and the highest silica (SiO2)
Felsic
Large igneous provinces (LIPS') such as the columbia river plateau are broad pleateaus built by successive basaltic lava flows called ______
Flood Basalts
During subduction, volatiles such as H2O and CO2 are realses from the descending oceanic plate which lower the melting point of the hot rock above it, causing a melt to form in a process called _______
Flux melting
The rate of change in temperature with depth is called the:
Geothermal Gradient
Cementation/ Compaction
Gluing together of sediment and rock
What high grade metamorphic rock is typically composed of alternating felsic and mafic layers that range in thickness from millimeters to meters?
Gneiss
What perssure-temperature environment produces a blue amphibole called glaucophane?
High Pressure, Low Temperature
nonfoliated metamorphic rock
Hornfels, Quartzite, Marble
Ultramafic
Igneous rocks with low silica content and very high levels of magnesium and iron. Periodite, dunites, and doirite are examples.
Volcanic ash, or ash mixed with lapilli, typically deposited from a pyroclastic flow, form a/an ____ when transformed into a coherent rock after cooling and solidification.
Ignimbrite
The presence of certain minerals, known as ___ minerals, indicate the metamorphic grade which corresponds to the pressure and temperature of the parent rock was exposed to.
Index
Transgression vs. Regression
Ingression, Regression, and Transgression. A transgression is a landward shift of the coastline while regression is a seaward shift. The terms are applied generally to gradual changes in coast line position without regard to the mechanism causing the change.
Neocrystallization
Initial minerals become unstable and change to new minerals, original minerals are digested by chemical reaction
A magma with >55% and <65% SiO2 would be classified as a _____ type magma?
Intermediate
Plutons
Intrusive igneous rock bodies, including batholiths, stocks, sills, and dikes, formed through mountain-building processes and oceanic-oceanic collisions; can be exposed at Earth's surface due to uplift and erosion.
Igneous rock with a course grained interlocking crystalline texture is typically _____ and therefore has a _____ cooling rate.
Intrusive; slow
Which four elements make up approximately 91% of the Earths Mass?
Iron (FE), Oxygen (O), Silicon (SI), and Magnesium (MG)
Wet, ash-rich debris flows formed from the mixture of volcaniclastic debris with snow, ice, rain or water produce a volcanic debris flow with the consistency of wet cement is called
Lahar
The tranformation of a loose sediment into a solid rock is referred to as _________. Thus process involves two steps, compaction wher the weight of the overlying material squeezes out water and air trapped between clasts and ____ where sediments are stuck together by minerals that precipitate from groundwater to form a cohert sedimentary rock.
Lithification, Cementation
Plate Tectonics theory explains of all of the following except:
Location of polar ice caps
Shield volcanoes from broad, gentle domes due to the ____ viscosity of the lavas, causing them to spread out of large areas.
Low
Volatiles are released from subducting oceanic lithosphere, hydrous minerals, and water-rich sediments, which causes melting in the overiding plate due to volatiles ____ (Raising/Lowering) the melting point of minerals in the mantle wedge above.
Lowering
Lava vs. Magma
Magma is composed of molten rock and is stored in the Earth's crust. Lava is magma that reaches the surface of our planet through a volcano vent.
The heat source for hot spot volcanism is a ____ a column of very hot rock rising up through the mantle to the base of the lithosphere
Mantle Plume
Recrystalization of limestone forms a nonfoliated rock called _____ composed of interlocking calcite crystals
Marble
If the ripple crest is symmetrical, that indicates formation within a _____ enviornment while an inclined ripple crest indicates formation within a ______ environment
Marine; Fluvial
Continental Crust is _________ buoyant, and _________ dense than oceanic crust.
More, Less
As you increase the silica content and decrease the temperature of a magma, it becomes ____ viscous, typiaclly resulting in ____ style eruptions.
More; Explosive
Tephra (cinder) cone
Much steeper, much shorter, a lot of pyroclasts, not much lava, can't pack on pyroclasts for very high-nothing to consolidate it together
____ is the growth of new mineral crystals that differ from those of the parent rock due to chemical reactions
Neocrystalization
Based on Bowen's Reaction series, as you cool a mafic melt, what is the first mineral expected to crystalize?
Olivine
active volcano
One that is erupting or shows signs that it may erupt in the near future.
orogenic belts
Orogeny refers to forces and events leading to a large structural deformation of the Earth's lithosphere (crust and uppermost mantle) due to the interaction between tectonic plates. Orogens or orogenic belts develop when a continental plate is crumpled and is pushed upwards to form mountain ranges, and involve a great range of geological processes collectively called orogenesis. How mountains are built on continents.
Convection of the liquid iron alloy that composed the ___ generates the Earth's magnetic field. It remains molten despite the great pressure due to the extreme heat not allowing atoms to form a solid crystalline structure.
Outer Core
lithostatic overburden
Overburden pressure, also called lithostatic pressure, confining pressure or vertical stress, is the pressure or stress imposed on a layer of soil or rock by the weight of overlying material.
Which two gases compose 99% of Earth's Atmosphere?
Oxygen (O2) and Nitrogen (N2)
Basalt flows whose surfaces are warm and pasty wrinkle into smooth, glassy, rope-like ridges called _____
Pahoehoe
Decompression Melting
Partial melting of hot mantle rock when it moves upward and the pressure is reduced to the extent that the melting point drops to the temperature of the body.
_____ transforms one mineral into another mineral with the same composition but a different crystal struction
Phase Change
When submarine volcanic eruptions occur, the lava is rapidly quenches forming a blob with a glassy rind called a ____
Pillow Basalts
A large body of magma emplaced within the crust is called a _____
Pluton
Two different minerals (like diamond and graphite) that have the same composition but different crystal structures are called _____
Polymorphs
A sedimentary rock composed of gravel-sized clasts with pointed edges in a silt - or clay sized matric would be classified as a _____ and _____
Poorly-Sorted, Angular
The sedimentary deposits formed from glacial activity are typically ____ and ____ called glacial till, due to how ice transports and deposits clasts.
Poorly-Sorted, angular.
Erosion
Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation)
A ____ is the "parent" rock that undergoes a solid-state (without melting) transformation in response to changes in pressure and/or temperate.
Protolith
_____ is a felsic volcanic rock that consists of tiny bubles, each of which is surronded by a thin wall of glass that forms from quickly cooling, volatile-rich frothy lava.
Pumice
A fine grain crystalline texture with a glassy groundmass typically results from magamas which cooled ___ and ____ ground
Quickly, Above
____ changes the size and shape of grains without changing the mineral compositon or struction making up the grains, typically resulting in larger, interlocking grains.
Recyrstallization
Scientists call this the expanding universe theory. This is demonstrated by the _______ shift observed in light emitted by distant stars.
Red
formation
Relative disposition of parts.
A large continent can split into smaller ones by the process of ________
Rifting
intermediate rock or magma
Rock with a chemical content between felsic and mafic compositions.
dunes
Sand accumulates when there is an obstruction across the wind path. The more sand gets collected, the steeper the slope will be.
chemical rock
Sedimentary rock that forms when minerals crystallize from a solution
Layering
Separating components of a design individually or into groups in order to make specific adjustments
shear (of rocks)
Shear is the response of a rock to deformation usually by compressive stress and forms particular textures. ... The process of shearing occurs within brittle, brittle-ductile, and ductile rocks. Within purely brittle rocks, compressive stress results in fracturing and simple faulting.
Biochemical sedimentary rock, one of four major sedimentary rock classes, typically consists of ___ and is composed of ____
Shell Fragments, Calcium Carbonate
Volcano Types
Shield, Cinder, Strato
Magmas are broadly classified into four categories based on the ____ weight percentage.
Silica
_____ minerals are the most common crust minerals, composing of >95% of the continental and oceanic crust and most the mantle.
Silicate
Silicate Minerals are distinguished from each other by the ways in which the _____ that compose them are linked or arranged
Silicon-oxygen tetrahedra
What is the feature called where an igneous intrusion is injected parallel to the bedding or layering of the rock?
Sill
______ and _____ forces contribute to driving tectonic plate motions, with some contribution from convection within the mantle.
Slab-Pull, Ridge-Push
List in order of increasing metamorphic grade the foliated metamorphic rocks formed from a shale (pelitic) protolith.
Slate, Phyllite, Schist, Gneiss, Migmatite
ripple marks
Small waves of sand that develop on the surface of a sediment layer by the action of moving water or air.
The Earth's magnetic field deflects the _____ being continuously emitted from the sun that is composed of fast moving, high energy particles.
Solar Wind
intrusive magma
Solidifies at a depth; has a coarse grain. Example is granite
extrusive magma
Solidifies at or near the surface; cools quickly and has a fine grain. Example basalt
The degree to which all clasts in a sediementary rock are the same size or variety of different sizes is referred to as
Sorting
Elements greater than atomic number 5 (boron) are created through a process called ______
Stellar Nucleosynthesis
Large, typically felsic cone-shaped volcanoes with steep slopes composed of layers of lava, tephra/ash and volcaniclastic debris are called
Stratovolcanoes
Stress vs. Strain
Stress is the total force acting on crustal rocks per unit of area Strain is the deformation of materials in response to stress
Compression
Stress that squeezes rock until it folds or breaks
tension
Stress that stretches rock so that it becomes thinner in the middle
Geologists use the term _____ to refer to the process where the surface of the crust sinks over a long period of time, allowing thick piles of sedimentary rocks to accumulate.
Subsidence
Geologist use the term _____ for unconsolidated fragments resulting from an eruption
Tephra
Weathering
The breaking down of rocks and other materials on the Earth's surface.
pyroclastic flow
The expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption
Silica content of magma
The main factor that accounts for the difference between quiet and explosive volcanic eruptions is
exhumation
The process (involving uplift and erosion) that returns deeply buried rocks to the surface.
Recrystallization
The process by which bonds between atoms in minerals break and re-form in new ways during metamorphism.
fractional crystallization
The process by which the crystals formed in a cooling magma are segregated from the remaining liquid at progressively lower temperatures.
chemical weathering
The process that breaks down rock through chemical changes
Lithification
The process that converts sediments into solid rock by compaction or cementation.
metamorphic zone
The region between two metamorphic isograds, typically named after an index mineral found within the region.
Geologists refer to a point where three plate boundaries meet as a ______
Triple Junction
Weather on our planet is limited to what layer of the atmosphere?
Troposphere
Underwater debris flows called ____ leave normally graded deposits due to settling out in water with the larger clasts towards the bottom and the smaller clasts towards the top.
Turbidity currents
Pahoehoe vs. Aa
Two major types of basaltic lava flows: Pahoehoe: very smooth or ropey lava, looks like flowing toothpaste Aa: broken jumbles of sharp fragments with rough edges
The strongest portion of the magnetic field is called the _________, it is located about 3,000 and 10,500 km away from earth and stop high energy cosmic rays.
Van Allen Radiation Belts
flood basalt
Vast sheets of basalt that spread from a volcanic vent over an extensive surface of land; they may form where a rift develops above a continental hot spot, and where lava is particularly hot and has low viscosity.
Volcanic gases come out of a solution as pressure is released while magma is rising during an eruption, the last bubles to form are trapped within the cooling lava generating ____
Vesicles
transporting medium
Water, Wind, Ice
Aeolian procecsses selectively sort clasts based on grain size. Given this information, what sorting characteristics and grain size would you expect sediments in a desert enviornment
Well sorted, sand-sized clasts
How is magma formed?
When Metamorphic or any rock melts it will form magma
Compaction rock
When pieces of a rock are pushed together. If "glue" is there too, a new rock can form.
Assimilated wall rock does not entierely melt within a magma body is called a _______
Xenolith
cement
a building material that is a powder made of a mixture of calcined limestone and clay
phase change
a change from one state (solid or liquid or gas) to another without a change in chemical composition
Diagenesis
a collective term for all the chemical, physical, and biological changes that take place after sediments are deposited and during and after lithification
mantle plume
a column of very hot rock rising up through the mantle
Cratons
a large, stable block of the earth's crust forming the nucleus of a continent.
columnar jointing
a pattern of cracks that forms during cooling of molten rock to generate columns
metamorphic grade
a representation of the intensity of metamorphism, meaning the amount or degree of metamorphic change
Breccias
a rock composed of fragments of earlier rocks bonded together
Schistosity
a type of foliation characteristic of coarser-grained metamorphic rocks; such rocks have a parallel arrangement of platy minerals such as the micas
shield volcano
a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions
explosive eruption
an eruption that is thick and sticky, has a high gas content, and is high in silica
porphyritic texture
an igneous texture consisting of large crystals embedded in a matrix of much smaller crystals
The smoothness or roughness of clasts composing a sedimentary rock is referred to as _____
angularity
Ignimbrites
ash flow tuff
A single layer of sediment or sedimentary rock with a recognizable top and bottom is called a _____
bed
The process where minerals such as quartz and calcite precipitate from groundwater and fill the remaing spaces between clasts is referred to as _____
cementation
types of sedimentary rocks
clastic, chemical, organic, biochemical
Strato Volcano (composite cone)
conical, steep-side, symmetrical volcano (ratio of height to breadth relatively large) composed of alternating layers of silicic lavas and pyroclastics. Typical of subduction zone volcanism.
Viscosity of magma
depends on its silica content and temperature
Deltas
deposits of sand and soil at the mouth of a river form
Mafic
describes magma or igneous rock that is rich in magnesium and iron and that is generally dark in color
aphanitic texture
fine grained
foliated vs non-foliated
foliated has a banded appearance and particles that align evenly. non-foliated has particles that are scattered.
The parallel alignments of platy or elongate minerals in response to a differntial stress is called _____
foliation
mud cracks
form when fine-grained sediments at the bottom of a shallow body of water are exposed to the air and dry out
regional metamorphism
formation of metamorphic rock bodies that are hundreds of square kilometers in size
pyroclastic debris
fragmented material that sprayed out of a volcano and landed on the ground or sea floor in solid form
Volatiles
gaseous components of magma dissolved in the melt. They will readily vaporize at surface pressures
pillow basalt
glass-encrusted basalt blobs that form when magma extrudes on the sea floor and cools very quickly
Turbidity currents generate
graded bedding
Turbidites
graded layers of terrigeneous sand interbedded with finer pelagic sediments of the deep sea floor
The diameter of clasts composing a sedimentary rock is referred to as _______
grains sizeang
metamorphic facies
groupings of metamorphic rocks of various mineral compositions formed under different grades of metamorphism from different parent rocks
phaneritic texture
igneous rock texture in which minerals are easily visible without magnification
felsic magma
magma with a high silica content and large volume of gas (explosive eruptions)
The continental shields consist mostly of
metamorphic and igneous rocks
pressure solution
metamorphic formation process; happens when a rock is squeezed more strongly in one direction that in others at relatively low pressures and temperatures, in the presence of water. Mineral grains dissolve where their surfaces are pressed against other grains, producing ions that migrate through the water to precipitate elsewhere.
thermal metamorphism
metamorphism caused by heat conducted into country rock from an igneous intrusion
burial metamorphism
metamorphism due only to the consequences of very deep burial
dynamic metamorphism
metamorphism that occurs as a consequence of shearing alone, with no change in temperature or pressure
index materials
minerals that form within specific temperature and pressure ranges during metamorphism
hydrothermal metamorphism
occurs when very hot water reacts with rock, altering its mineralogy and chemistry
strata (beds)
parallel layers of sedimentary rock
Lapilli
pebble like bits of magma that cool in the air
plastic deformation
permanent change in shape by bending and folding
crustal subsidence
regions once covered by ice during the last ice age were uplifted when all ice was gone
Small, elongated ridges that form on a bed surface at right angles to direction of current flow (water/wind) are called ______
ripple marks
organic rock
sedimentary rock that forms from remains of organisms deposited in thick layers
clastic rock
sedimentary rock that forms when rock fragments are squeezed together under high pressure
biochemical rock
sedimentary rock that was formed by organisms or contains the remains of organisms
Sills
sheetlike intrusions that are oriented parallel to previous rock units
bedding plane
the boundary between two beds
shock metamorphism
the changes that can occur in a rock due to the passage of a shock wave, generally resulting from a meteorite impact
angularity
the degree of edge or corner smoothness
Heat Transfer
the flow of thermal energy from higher temperature to lower temperature
igneous activity
the formation, movement, and in some cases eruption of molten rock
deposition (of rocks)
the geological process in which sediments, soil and rocks are added to a landform or land mass
Groundmass
the matrix of smaller crystals within an igneous rock that has porphyritic texture
Protolith
the original rock from which a metamorphic rock formed
magma chamber
the pocket beneath a volcano where magma collects
Metasomatism
the process by which a rock's overall chemical composition changes during metamorphism because of reactions with hot water that bring in or remove elements
partial melting
the process by which different minerals in rock melt at different temperatures
Stratification
the process in which sedimentary rocks are arranged in layers
magma mixing
the process of altering the composition of a magma through the mixing of material from another magma body
geothermal gradient
the rate of change in temperature with depth
Fossils
the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
Bowen's Reaction Series
the simplified pattern that illustrates the order in which minerals crystallize from cooling magma according to their chemical composition and melting point
types of metamorphism
thermal, burial, dynamic, regional, hydrothermal, subduction, shock
When relative sea level drops and the shoreline migrates seaward, this process is called _____
transgression
Lahars
volcanic mudflows
Evaporties
when the water in these seas or lakes evaporates, deposits of salts are left behind
Calderas Volcanoes
• Large • Explosive • Felsic pyroclastic material. • magma chamber roof collapses Ex: Yellowstone, Crater Lake