Geology Test #1 – Flashcards
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asthenosphere
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the soft layer of the mantle that the lithosphere floats on
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climate system
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all the earth system components that determine climate on a global scale and how climate changes with time
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core
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the central part of the Earth
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crust
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the outer layer of the Earth
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earth system
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all of the parts of our planet and all their interactions
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fossil
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the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil
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geodynamo
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the self-sustaining process responsible for maintaining the earth's magnetic field in which the kinetic energy of convective motion of the earth's liquid core is converted into magnetic energy
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geosystem
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specialized subsystems that describe specific types of terrestrial behavior
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inner core
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a dense shpere of solid iron and nickel in the center of the Earth
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lithosphere
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the solid part of the earth consisting of the crust and outer mantle
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magnetic field
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the lines of force surrounding a permanent magnet or a moving charged particle
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mantle
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the layer of the earth between the crust and the core
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outer core
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a layer of molten iron and nickel that surrounds the inner core of the Earth
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plate tectonic system
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the convecting mantle and its overlying mosaic of lithospheric plates
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principle of uniformitarianism
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Processes that act upon the Earth today are the same processes that have acted upon it in the past. The present is the key to the past.
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scientific method
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a method of investigation involving observation and theory to test scientific hypotheses
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seismic wave
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A vibration that travels through Eath carrying the energy released during an earthquake
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topography
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The art of representing on a map the physical features of any locality or region with accuracy.
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continental drift
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the gradual movement and formation of continents (as described by plate tectonics)
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geodesy
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the branch of geology that studies the shape of the earth and the determination of the exact position of geographical points
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island arc
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a string of islands foremd by the volcanoes along a deep ocean trench
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isochron
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a contour that connect rocks of equal age
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magnetic anomaly
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evidence that the ocean floor is spreading apart. It shows that the earth's magnetic field has reversed several times throughout the earth's history
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magnetic time scale
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the history of magnetic reversals through geologic time
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pangaea
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the name of the single landmass that broke apart 225 million years ago and gave rise to today's continents
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plate tectonics
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the branch of geology studying the folding and faulting of the earth's crust
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relative plate velocity
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velocity at which one plate moves relative to another
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rodinia
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supercontinent that formed about 1.1 billion years ago and began to break up 750 million years ago
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seafloor spreading
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process of plates moving apart and asthenosphere filling in
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spreading center
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a linear zone in the sea floor along which magma rises and from which adjacent crustal plates are moving apart.
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subduction
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a geological process in which one edge of a crustal plate is forced sideways and downward into the mantle below another plate
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transform fault
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boundaries where plates slide past each other and lithosphere in neither created nor destroyed
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anion
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a negatively charged ion
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atom
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smallest particle still retaining the chemical characteristics of an element
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atomic mass
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the average mass of all the isotopes of an element
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atomic number
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number of protons in the nucleus of an atom
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bedding
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the formation of parallel layers of sediment as particles settle to the bottom of the sea, a river, or a land surface
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cation
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a positively charged ion
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chemical and biochemical sediments
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new chemical substances that form by precipitation when some of a rock's components dissolve during weathering and are carried in river waters to the sea
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chemical reaction
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a process that changes one set of chemicals into another set of chemicals
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cleavage
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tendency of a crystal to break along flat planar surfaces
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contact metamorphism
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process in which rocks are transformed by contact with an intrustion
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covalent bond
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a chemical bond that involves sharing a pair of electrons between atoms in a molecule, a chemical bond that involves sharing a pair of electrons between atoms in a molecule
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crystal
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a rock formed by the solidification of a substance
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crystal habit
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shape in which its individual crystals or aggregates of crystals grow
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crystallization
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the atoms of a gas or liquid coming together in the proper chemical proportions and crystalline arragement
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density
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the mass per unit volume of a material
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electron
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a negatively charged particle
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electron sharing
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the sharing of an electron between two atoms
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electron transfer
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the donation of valence electrons from one atom to anther to form a cation and an anion
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erosion
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process by which fragments of rock and soil are broken off from the ground surface and carried away
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extrusive igneous rock
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an igneous rock, such as basalt, made of fine grains. It is formed when magam cools quickly on Earth's surface
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foliation
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the arrangement of leaflike layers in a rock
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fracture
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a crack in the earth's crust resulting from the displacement of one side with respect to the other
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hardness
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a measure of how easily a mineral can be scratched.
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hydrothermal solution
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hot solutions that are formed around bodies of molten rock
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igneous rock
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rock formed by the solidification of molten magma
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intrusive igneous rock
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forms when magma cools in earth's surface. (large crystals)
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ionic bond
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a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains to electron to form a negative ion
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isotope
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one of two or more atoms with the same atomic number but with different numbers of neutrons
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lithification
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the set of processes transforming sediment into rocks
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luster
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the appearance of a mineral surface in reflected light: metallic vs. nonmetallic
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metallic bond
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a chemical bond in which electrons are shared over many nuclei and electronic conduction occurs
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metamorphic rock
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rock formed when any kind of rocks recrystallize in response to elevated temperature, increased pressure, chemical change, and/or deformation
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mineral
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solid homogeneous inorganic substances occurring in nature having a definite chemical composition
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mineralogy
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the branch of geology that studies minerals: their structure and properties and the ways of distinguishing them
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mohs scale of hardness
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a scale based on the ability of one mineral to scratch another
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neutron
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subatomic particle found in the nucelus; has a neutral charge
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nucleus
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the positively charged dense center of an atom
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ore
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rich deposits of minerals from which valuable metals can be recovered profitably
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polymorph
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alternative structures for a single chemical compound
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precipitate
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crystals that drop out of a solution
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proton
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positively charged particle of an atom
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regional metamorphism
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pressure and heat from mountain-building or plate-tectonic movements
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rock
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solid, cohesive aggregate of one or more minerals or glass
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rock cycle
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sequence of events in which rocks are formed, destroyed, altered, and reformed by geological processes
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sediment
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solid rock or mineral fragments transported and deposited by wind, water, gravity, or ice, precipitated by chemical reactions, or secreted by organisms, and that accumulates as layers in loose, unconsolidated form
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sedimentary rock
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rock formed by the lithification of sediments usually after transportation; may also be formed by chemical precipitation
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siliciclastic sediments
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physically deposited particles, such as grains of quartz and feldspar derived from weathered granite
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specific gravity
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the density of a substance relative to the density of water
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streak
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is the color of a mineral when it is powdered.
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texture
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the size, shape, and arrangement of mineral grains, or crystals in a rock
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vein deposit
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A metal-rich accumulation of mineral matter that occurs along a fracture or bedding plane
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weathering
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the decompocition and disintegration of rocks and minerals at the earth's surface by a mechanical and chemical process
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andesite
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Intermediate in composition between mafic basalt and felsic rhyolite,
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basalt
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A hard, dense, dark volcanic rock composed chiefly of plagioclase, pyroxene, and olivine, and often having a glassy appearance.
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batholith
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large mass of intrusive igneous rock believed to have solidified deep within the earth
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concordant construction
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boundaries that lie parallel to layers of preexisting bedded rock
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country rock
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rock that surrounds intrusive igneous rock
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dacite
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a gray volcanic rock containing plagioclase and quartz and other crystalline minerals
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decompression melting
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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.
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dike
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thin pluton that forms when magma enters a crack in rock; cuts through pre-existing material
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diorite
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a granular crystalline intrusive rock
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discordant intrusion
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masses of rock that cut across the layers of the country rock they intrude
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extrusive igneous rock
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formed from material that has erupted onto the earth's surface
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felsic rock
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rich in felsic minerals like quartz and feldspar. are light in colour and weight, ex. granite, rhyolite, lower siliccate content, more fluid
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fluid-induced melting
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melting that takes place when water laden sediments on a subducting oceanic plate are carried downward into the subduction zone
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fractional crystallization
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process in which the crystals formed in a cooling magma are segregated from the remaining liquid
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gabbro
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A mafic, coarse-grained igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar.
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granite
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a coarse-grained igneous rock composed chiefly of orthoclase and albite feldspars and of quartz, usually with lesser amounts of one or more other minerals, as mica, hornblende, or augite.
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granodiorite
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light colored felsic rock that looks like granite but its predominant feldspar is plagioclase not orthoclase
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hydrothermal vein
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veins that are filled with minerals that contain large amounts of chemically bound water and are known to crystalize from hot-water sollutions
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intermediate igneous rock
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rocks that are midway between mafic and felsic
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intrusive igneous rock
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formed when magma solidifies within bodies of pre-existing rock
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mafic rock
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Silica-deficient igneous rock with a relatively high content of magnesium, iron, and calcium.
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magma chamber
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a pocket beneath the earth's surface that holds magma
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magmatic differentiation
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a process by which rocks of varying composition can arise from a uniform parent magma
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obsidian
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hard, black, glassy volcanic rock
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ophiolite suite
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assemblages of rocks that were characteristic of the seafloor but were found on land
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partial melting
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The process in which a silicate rock only partially melts as it is heated, to form magma that is more silica rich than the origional rock.
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pegmatite
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a form of igneous rock consisting of extremely coarse granite resulting from the crystallization of magma rich in rare elements
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peridotite
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a dark coarse-grained igneous rock consisting principally of olivine
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pluton
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large mass of intrusive igneous rock believed to have solidified deep within the earth
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porphyry
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any igneous rock with crystals embedded in a finer groundmass of minerals
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pumice
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igneous- very light gray to a medium gray- contains a large number of gas bubbles each surrounded by a thin layer of volcanic glass- looks something like a sponge- very light weight- most pieces will float in water- flow lines or bands may show
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pyroclast
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rocks that form when broken pieces of lava are thrown high into the air
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rhyolite
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A fine-grained, felsic, igneous rock made up mostly of feldspar and quartz.
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sill
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a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock
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stock
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smaller plutons
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tuff
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a light, porous rock formed by consolidation of volcanic ash
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ultramafic rock
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Rock composed entirely or almost entirely of ferromagnesian minerals.
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vein
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deposits of minerals found within a rock fracture that are foreign to the host rock
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viscosity
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resistance of a substance to flow
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volcanic ash
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Somewhat larger volcanic debris, up to 5 millimeters in diameter, which is shot into the atmosphere during an eruption.
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andesitic lava
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a lava of medium thickness (viscosity)
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ash-flow deposit
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deposits from fissure eruptions of pyroclastic materials on continents that produce extensive sheets of hard volcanic tuffs
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basaltic lava
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lava of mafic composition that has a low silica content, erupts at high temperatures, flows readily; extrusive equivalent of gabbro
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caldera
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a large crater caused by the violent explosion of a volcano that collapses into a depression
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crater
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bowl-shaped pit found at the summit of most volcanoes, centered on the vent
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diatreme
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volcanic vent formed by the explosive escape of gases and often filled with breccia
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fissure eruption
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the eruption of magma out of a crack in the lithosphere, rather than from a single pipe or vent
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flood basalt
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Basaltic lava that gently erupts in great volume from cracks at the earth's surface to cover large areas of land and forms plateaus
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hot spot
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volcanic center found at the beginning of progressively older aseismic ridges or within a continent far from a plate boundary
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hydrothermal activity
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circulation of water through hot volcanic rocks and magmas, produces hot springs and geysers on the surface
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lahar
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an avalanche of volcanic water and mud down the slopes of a volcano
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large igneous province
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voluminous emplacement of predominantly mafic extrusive and intrusive rock whose origins lie in the processes other than "normal" seafloor spreading
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mantle plume
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Narrow column of hot mantle rock that rises and spreads radially outward.
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pyroclast
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volcanic rock fragmented ejected into the air during an eruption
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rhyolitic lava
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lava that is richest in silica, sticky and least fluid lava
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shield volcano
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A low, flat, gently sloping volcano built from many flows of fluid, low-viscosity basaltic lava
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stratovolcano
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A composite volcanic cone built of interlayered lava flows and pyroclastic materials
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volcanic geosystem
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total system of rocks, magmas, and interactions needed to describe the entire sequence of events from melting to eruption
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volcano
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a fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt
