Geology Definitions Comprehensive Exam Questions And Answers Pass At First Attempt!!!

The study of the Earth, including our planet's composition, behavior and history - correct answer geology A reasonable idea that has the possibility of being correct, but has not yet been proven - correct answer hypothesis The relatively rigid, nonflowable, outer 100 to 150 km thick layer of the earth; constituting the crust and the top part of the mantle - correct answer lithosphere The rock layer that makes up the outermost layer of the earth - correct answer crust The seismic-velocity discontinuity that defines the boundary between the Earth's crust and mantle - correct answer moho The variation in depth of the ocean floor which defines submarine ridges, plains and trenches - correct answer bathymetry The thick layer of rock below the Earth's crust and above the core - correct answer mantle One of about twenty distinct pieces of the relatively rigid lithosphere - correct answer plate The dense, iron rich center of the earth. - correct answer core The variation in elevation of the land surface which defines plains, mountains and valleys. - correct answer topography The layer of the mantle that lies between 100-150 km and 350 km deep. It is relatively soft and can flow when acted on by force. - correct answer asthenosphere A scientific idea supported by an abundance of evidence that has passed many tests and failed none - correct answer theory The gradual widening of an ocean basin as new oceanic crust forms at a mid-ocean ridge axis and then moves away from the axis - correct answer sea-floor spreading An isolated submarine mountain - correct answer seamount The process of two (2) buoyant pieces of lithosphere converging and squashing together - correct answer collision the theory that the outer layer of the Earth (the lithosphere) consists of separate plates that move with respect to one another - correct answer plate tectonics The change of the Earth's magnetic polarity. When this change occurs, the magnetic field flips from normal to reversed polarity or vice versa. - correct answer magnetic reversal The border between two adjacent lithospheric plates - correct answer plate boundary two lithospheric plates move apart from each other; they are marked by mid-ocean ridges. - correct answer divergent plate boundary one lithospheric plate slips laterally past another - correct answer transform plate boundary A deep elongate trough bordering a volcanic arc which defines the trace of a convergent plate boundary - correct answer trench the idea (hypothesis) that continents have moved and are still moving slowly across the Earth's surface - correct answer continental drift the process by which an oceanic plate bends and sinks down into the asthenosphere beneath another plate - correct answer subduction two plates move toward each other so that one sinks (subducts) beneath the other; only oceanic litosphere can subduct - correct answer convergent plate boundary 2-km-high submarine mountain belt that forms along a divergent oceanic plate boundary - correct answer mid-ocean ridge the way a mineral surface scatters light - correct answer luster a single, continous piece of a mineral bounded by flat surfaces that formed naturally as the mineral grew in unrestricted space - correct answer crystal homogenous, naturally occurring, solid inorganic substance with a definable chemical composition and an internal structure characterized by and orderly arrangement of atoms in a lattice - correct answer mineral the color of the powder produced by pulverizing a mineral on an unglazed ceramic plate - correct answer streak coherent, naturally occurring solid, consisting of an aggregate of minerals, mineral like substances or glass - correct answer rock produces smoothly curving, clamshell-shaped surfaces along which materials with no cleavage planes tend to break - correct answer conchoidal fracture a number representing the density of a mineral, as specified by the ratio between the weight of a volume of the mineral and the weight of an equal volume of water - correct answer specific gravity the resistance of a mineral to scratching - correct answer hardness basic building block of silicate minerals consists of one silicon atom surrounded by four onxygen atoms. This is called the silicon-oxygen - correct answer tetrahedron the tendency of a mineral to break along preferred planes of weakness in the mineral structure - correct answer cleavage composed of silicon-oxygen tetrahedra linked in various arrangements; most contain other elements too - correct answer silicate minerals an exposure of rock that is still attached to the Earth's crust - correct answer outcrop a mineral or form of a mineral that is particularly beautiful and/or rare, and thus has value - correct answer gem the internal arrangement of atoms or ions within a mineral - correct answer crystal structure a list of ten minerals in a sequence of relative hardness, with which other minerals can be compared - correct answer Moh's Hardness Scale a vast composite, intrusive, igneous rock body up to several hundred kilometers long and 100 km wide, formed by the intrusion of numerous plutons in the same region - correct answer batholith a tabular intrusion of rock that cuts across the layering of country rock - correct answer dike a nearly horizontal table-top-shaped tabular intrusion that occurs between the layers of country rock - correct answer sill molten rock beneath the Earth's surface - correct answer magma an open hole in an igneous rock formed by the preservation of gas bubles in magma as the magma cools into solid rock - correct answer vesicle molten rock that has flowed onto the Earth's surface - correct answer lava a process by which a magma incorporates chemicals from the wall rock of the magma chamber or blocks of detached wall rock that have fallen into the magma - correct answer assimilation a rock that forms by the freezing of lava, above the ground, after it flows or explodes onto the surface and comes into contact with the atmosphere or ocean - correct answer extrusive igneous rock a relic of wall rock (one that did not melt) surrounded by an intrusive igneous rock - correct answer xenolith a rock formed by the freezing of magma underground - correct answer intrusive igneous rock a rock made from fragments blown out of a volcano during an explosion. The fragments were then packed or welded together to form the rock - correct answer pyroclastic rock an igneous rock that consists entirely of glass, or of tiny crystals surrounded by a glass matrix - correct answer glassy igneous rock occurs when a melt is produced when the minerals with the lowest melting temperature melt, while the other minerals remain solid - correct answer partial melting an irregular or blob-shaped intrusion. It can range in size from tens of meters across to tens of kilometers across - correct answer pluton succession of sedimentary beds - correct answer strata a sedimentary rock made up of minerals that precipitate directly from water solution - correct answer chemical sedimentary rock a characteristic of sedimentary deposits that pertains to the character of bedding (layering) and/or the surface features of a bed formed during deposition - correct answer sedimentary structure inland migration of a shoreline resulting from a rise in sea level - correct answer transgression a sedimentary rock formed from carbon-rich relicts of organisms - correct answer organic sedimentary rock the phase of lithification in which minerals precipitate from the groundwater and partially or completely fill the spaces between clasts, attaching each grain to its neighbor - correct answer cementation process by which sediment settles out of a transporting medium - correct answer deposition a sedimentary rock formed from material (such as shells) produced by living organisms - correct answer biochemical sedimentary rock seaward migration of a shoreline, caused by a lowering of sea level - correct answer regression sediment that has undergone changes at the Earth's surface, including reactions with rainwater and the addition of organic material - correct answer soil transformation of loose sediment into solid rock through compaction and cementation - correct answer lithification process which removes earth surface material from its substrate - correct answer erosion the range of clast sizes in a collection of sediment - correct answer sorting a sedimentary rock consisting of cemented-together detritus derived from the physical weathering of preexisting rock - correct answer clastic sedimentary rock the vertical sinking of the Earth's surface in a region, relative to a reference plane - correct answer subsidence involves heat pressure and shearing over a broad region. It is usually the result of deep burial during an orogeny (mountain building event) - correct answer regional metamorphism the original rock from which a metamorphic rock is formed - correct answer protolith a set of metamorphic mineral assemblages indicative of metamorphism under a specific range of pressures and temperatures - correct answer metamorphic facies caused by heat conducted into country rock from an igneous intrusion - correct answer contact metamorphism a rock that is formed when gneiss is heated high enough so that it begins to partially melt, creating layers or lenses, of new igneous rock that mix with layers of the relict gneiss - correct answer migmatite 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 - correct answer metasomatism the region between two metamorphic isograds, typically named after an index mineral found within the region - correct answer metamorphic zone layering formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock - correct answer foliation due to the increase in temperature and pressure in a rock when it has been buried to a depth of several kilometers - correct answer burial metamorphism the region around a pluton in which heat transferred into the country rock and metamorphosd the country rock - correct answer metamorphic aureole a change that occurs in a rock due to interaction with high temperature water solutions - correct answer hydrothermal metamorphism an older, interior region of a continent. It is a region of long-lived stable continental crust where Precambrian rocks are exposed - correct answer shield occurs as a consequence of shearing alone, with no change in temperature or pressure - correct answer dynamic metamorphism an informal designation of the degree or intensity to which a rock has undergone metamorphism - correct answer metamorphic grade a curving chain of active volcanoes on the overiding plate near a subduction zone - correct answer volcanic arc the movement of one lithosphere plate with respect to another plate - correct answer relative plate velocity a column of very hot mantle material that rises upward from a fixed location in the mantle - correct answer mantle plume continental margin that is also a plate boundary - correct answer active margin drives the plates away from the mid-ocean ridge. Gravity causes the elevated lithosphere to move away from the ridge axis. - correct answer ridge-push force a vent along a mid-ocean ridge where hot water spews out carrying with it a cloud of suspended minerals. When the hot water mixes with sea water, the dissolved sulfides precipitate. - correct answer black smoker a continental margin that is not a plate boundary - correct answer passive margin applied to oceanic lithosphere at a convergent margin as the plate goes downward because the plate is denser than the asthenosphere - correct answer slab-pull force a location at the base of the lithosphere where melting occurs because a column of very hot mantle material rises upward from a fixed location in the mantle - correct answer hot spot a point where three lithospheric plate boundaries intersect - correct answer triple junction a magnetic entity that has a north and south end - correct answer magnetic dipole the movement of a plate relative to a fixed point in the mantle - correct answer absolute plate velocity a linear belt along which continental lithosphere stretches and pulls apart - correct answer continental rift the record of ancient magnetism preserved in rock - correct answer paleomagnetism the process of two boyant pieces of lithosphere converging and squashing together - correct answer collision basaltic lava flow with a rubbly, sharp surface - correct answer A'a' a subareal volcano with a broad, gentle dome, formed by low viscosity basaltic lava - correct answer shield volcano very fine particulate matter erupted by a volcano. Consists of glass shards formed during the rapid cooling of lava droplets erupted into the air and/or tiny rock particles blasted into the air by the volcanic explosion - correct answer ash an eruption that yields mostly lava and not ash - correct answer effusive eruption a large circular depression with steep walls and a fairly flat floor, formed after an eruption, as the center of the volcano collapses into the drained magma chamber below - correct answer caldera large, frozen blocks of rock, typically streamlined in shape, that formed when magma (ejected from a volcano) freezes in flight - correct answer bombs a subareal volcano consisting of a cone-shaped pile of tephra whose slope approaches the angle of repose - correct answer cinder cone an unconsolidated accumulation of pyroclastic material - correct answer tephra a thick slurry of volcanic ash and debris mixed with water from rivers and/or melted snow and ice from the flanks of the volcano - correct answer lahar marble to plum sized fragments of pyroclastic debris - correct answer lapilli large, cone shaped, subareal volcano consisting of alternating layers of lava and tephra - correct answer stratovolcano a circular depression at the top of a volcanic mound - correct answer crater large chunks of igneous rock blasted out of a volcano - correct answer blocks a basaltic lava flow with a smooth texture and rope-like ridges - correct answer pahoehoe a conduit from a magma chamber with the shape of a long crack through which magma rises and erupts at the surface - correct answer fissure a band between 103 and 180 degrees from an earthquake epicenter, as measured along the circumference of the earth, inside which S-waves do not arrive at seisograph stations - correct answer s-wave shadow zone seismic waves in which particles of material move back and forth perpendicular to the direction in which the wave itself moves - correct answer shear waves a series of smaller earthquakes that preceed a larger earthquake - correct answer foreshocks a large wave along the sea surface that is triggered by an earthquake - correct answer tsunami seismic waves that pass through the interior of the earth - correct answer body waves the point below the Earth's surface where the energy is released during an earthquake - correct answer hypocenter the transformation of seemingly solid sediment into a liquid like slurry, in response to ground shaking - correct answer liquefaction seismic waves that travel along the Earth's surface - correct answer surface waves an instrument that can record the ground motion from an earthquake - correct answer seismograph the point of the Earth's surface directly above the earthquake focus - correct answer epicenter seismic waves in which particles of material move back and forth parallel to the direction in which the wave itself moves - correct answer