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| loose rock material that forms a sloping fan-shaped mass at the point where a stream emerges from an upland area into a broad plain or valley |
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| widespread silicate minerals found in many igneous and metamorphic rocks |
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| the angle at which loose material will stand without sliding; it is measured from the horizontal |
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| a typically arch-shaped fold in rock in which the oldest rocks are in the core |
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| a layer of impermeable rock adjacent to one that is permeable |
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| an aquifer in which the level of the discharge area is lower than that of the recharge area, and the water is confined by an impervious layer; when this layer is penetrated, the natural pressure will raise the water to the surface |
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| a weak zone in the upper mantle that underlies the lithosphere |
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| an island formed of coral that is circular in shape with a central lagoon |
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| a fine-grained extrusive igneous rock formed mostly of feldspar and pyroxene |
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| layering visible in rocks that results from the settling of particles during deposition |
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| a stream in which large numbers of sand bars cause the stream to flow as a series of separating and uniting channels |
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| a widespread rock-forming mineral composed of calcium carbonate;a major constituent of limestones |
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| a layer of secondary calcareous material below the surface that results from the evaporation of soil moisture, which leaves behind the calcium carbonate held in solution |
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| a theory that suggests that catastrophic events are the cause of past geologic changes |
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| the alteration of rocks surrounding an intrusion due to the heat of the intrusion |
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| the theory that continents move slowly over time on a deep-seated viscous zone |
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| the gently sloping zone of shallowly submerged land that surrounds the continents |
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| the steeply sloping zone between the continental shelf and the true ocean's depths |
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| the boundary between two crustal plates that are moving toward each other |
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| the central part of the Earth; it is composed of a nickel-iron mixture and is divided into inner solid and outer liquid parts |
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| a form of bedding in which the layers are arranged at an angle to the depositional surface |
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| the outermost layer of the solid Earth; varies in thickness from 5 km below the oceans to 60 km below the mountain chains |
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| a homogeneous ordered solid having naturally formed faces and a limited chemical composition |
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| an alluvial deposit built out into a body of water by a stream |
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| an area where subsurface waters are discharged into streams or lakes |
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| the process of chemical weathering by groundwater in which minerals and rock material pass directly into solution |
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| the boundary between two crustal plates that are moving away from each other |
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| a landform consisting of a mass of sand accumulated and moved by the wind; the movement of sand from the downwind to the upwind side results in the movement of the dune in the direction of the wind |
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| the area of the Great Plains where a combination of drought and inappropriate farming practices resulted in severe soil erosion in the 1930s |
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| the process of removal and transport of fragments and particles of weathered rock |
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| a rock formed from a rapidly cooling magma extruded on the Earth's surface |
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| a plane within rocks along which movement has taken place |
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| a group of alumino-silicate minerals that are essential to the formation of igneous rocks |
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| a sub-planar rock fabric formed by the preferred orientation of platy minerals |
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| of system of organizing geological events that is usually presented in the form of a chart; the subdivision of geologic time |
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| the study of surface features on the Earth and their evolotion |
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| a body of ice that lies wholly or largely on land and shows evidence of flowing under the influence of gravity |
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| an intrusive igneous rock formed of quartz, feldspar, and mica |
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| subsurface water in the zone of saturation; this is the water that is present below the water table |
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| a compound consisting only of hydrogen and carbon; natural gas and petroleum are mixtures of hydrocarbons |
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| a preliminary assumption or explaination that accounts for a set of facts and is assumed to be true for the purpose of investigation and experimentation |
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| rocks formed by the cooling and solidification of a magma |
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| a rock formed by a slowly crystallizing magma intruded deep within the crust |
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| a condition of balance within the Earth's crust bt which mountaion chains are balanced by extensive "roots" that project downward, in the same manner as a floating iceberg |
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| a type of landform developed in areas underlain by limestones that are easily dissolved; characeristically, solution passages and caves are developed and spires of limestone may be left as the surrounding rock is removed |
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| varieties of an element that have the same number of protons and electrons but a different number of neutrons |
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| a shallow pond or lake on the edge of the ocean but separated from it |
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| a type of mass wasting in which material moves rapidly downward and outward along a surface of separation |
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| a hard red soil that results from intense chemical weathering of the surface in tropical regions |
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| molten rock; usually results from the eruption of a volcano |
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| the process whereby sediments are converted to solid rock by the process of compaction and cementation |
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Definition
| the oceanic and continental part of the crust together with the upper, brittle part of the mantle; it varies in thickness from 1-2 km at the ocean ridges to 140-160 km below the oceanic crust |
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| a mass of molten rock that, when cooled, will form an igneous rock |
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| the zone that lies between the core and the Earth's crust and is approximately 2300 km thick |
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| hot material rising through the mantle at "hot spots" |
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| a general term for the movement of large masses of material by landslides or by flowage or soil creep |
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| rocks that have been altered due to conditions of increased temperature and pressure |
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| small extraterrestrial bodies that enter the Earth's atmosphere and land on its surface |
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| a group of sheet-silicate minerals that have a platy appearance |
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| a substance that is usually inorganic and that has a characteristic crystalline structure tat can be used to identify it; rocks are composed of minerals |
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| an accumulation of sediment deposited by the action of a glacier |
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| a mud rock that will yeild oil by distillation |
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Definition
| an iron-magnesium-silicate mineral occurring in many igneous rocks |
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| the compression of a belt of the Earth's crust to form a mountain chain |
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| the portion of a rock formation that is exposed on the surface of the ground |
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| the study of remnant magnetism or the record of the Earth's past magnetic field |
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| a hypothetical single ancient supercontinent comprised of an amalgamation of all the continental crust present at the time |
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| in geology, ameasure of how easily water can pass through rock |
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| a small planetary body accreted from the original solar nebula |
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| the unifying theory that draws together continental drift and seafloor spreading into a unifying thoery of the evolution of the surface of the Earth |
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| a shallow lake occupying the lowest part of an enclosed basin |
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Definition
| refers to igneous rocks that have crystallized at great depth |
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| a measure of the volume of a rock that consists of space |
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Definition
| silicate minerals, usually black or dark green, that occur in both igneous and metamorphic rocks |
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Definition
| the most widely distributed and common rock forming mineral; composed of silicon dioxide |
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Definition
| the area that acts as a catchment for an aquifer |
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| a sedimentary rock aggregate formed of the skeletons of colonial organisms that lived below the surface of the ocean |
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Definition
| metamorphism occurring on a regional scale, usually in areas where lithospheric plates are converging |
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Definition
| the process by which material is slowly romoved by solution and is replaced by another maineral; this can occur atom by atom so that the original structure is retained |
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Definition
| the cyclic connection between the three major groups of rock in which weathering products at the surface are converted to sedimentary rocks and then to metamorphic and igneous rocks by an increase in temperature and pressure |
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Definition
| a regional metamorphic rock with coarse texture and a planar fabric |
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Definition
| the theory that the ocean floor is created at divergent plate boundaries as the plates are moved apart by mantle convection |
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Definition
| rocks formed by the erosion of rocks on the Earth's surface and the accumulation and burial of the erosion products |
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| accumulations of loose particles of organic and inorganic material that are the precursors of sedimentary rocks |
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| a depression in the surface of the ground often connecting to a cavern or subterranean passage |
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Definition
| the original cloud of rotating gas and dust from which the solar system was formed |
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Definition
| the system that consists of the sun and the planets, satellites, and asteroids that rotate around it; its age is considered to be about 4.56 billion years |
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Definition
| a layered structure, often forming mounds, that is built up over a long period of time by mats of cyanobacteria that trap sediment |
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Definition
| the process by which dense oceanic crust material is overriddenby lighter continental crust and sinks down into the mantle |
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| a reservoir for oil which the volatiles have escaped, and the sediment is impregnated with the residue |
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| a deposit formed of suspended material picked up by a storm |
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| a set of facts, propositions, or principles used to explain scientific phenomena; a description of the world that has met many observations and experimental tests |
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Definition
| unconsolidsted and unsorted sediments deposited directly by the action of ice |
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| a density current that carries sediments very rapidly from delta fronts across the continental slope to deposit as turbidites at the foot of the slope or on the abyssal plain |
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| "the present is the key to the past"; the idea that processes operating now on the Earth's surface also operated in the past |
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| sedimants resulting from the regular deposition of material due to annual seasonal influences; in glacial lake sediments, a lower, coarser layer is deposited in the summer, and a finer layer follows in the winter |
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| describes igneous rocks that have crystallized at the surface |
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| a law that implies that a vertical sequence of sediments will be the product of a series of environments that lay adjacent to each other laterally; the environments replace each other as they move laterally |
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| the upper surface of the saturated zone within bedrock |
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| the mechanical and chemical breakdown of rocks at the Earth's surface |
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