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Glossary of terms
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A-B | C-D | E-F | G-H | I-K | L-N | O-Q | R-T | U-Z | [Sources]

calcite: A mineral composed of calcium carbonate [LCOTE]

calving: Formation of icebergs by breaking off of glaciers entering the ocean [LCOTE]

Cambrian explosion: A rapid radiation of species that occurred as a result of a large adaptive space, including numerous habitats and a mild climate [LCOTE]

carbonaceous: A substance containing carbon, namely sedimentary rocks such as limestone and certain types of meteorites [LCOTE]

carbonaceous chondrites: Stony meteorites that contain abundant organic compounds [LCOTE]

carbonate: A mineral containing calcium carbonate such as limestone and dolostone [LCOTE]

carbon cycle: The flow of carbon into the atmosphere and ocean, the conversion of carbonate rock, and the return by volcanoes [LCOTE]

Cenozoic: An era of geologic time comprising the last 65 million years [LCOTE]

cephalopod: Marine mollusks including squids, cuttlefish, and octopuses that travel by expelling jets of water [LCOTE]

chalk: A soft form of limestone composed chiefly of calcite shells of microorganisms [LCOTE]

chert: An extremely hard, cryptocrystalline quartz rock resembling flint [LCOTE]

chondrule: Rounded granules of olivine and pyroxine found in stony meteorites called chondrites [LCOTE]

class: In systematics, the category of plants and animals below a phylum comprising several orders [LCOTE]

climate: The average course of the weather for a certain region over time [LCOTE]

coal: A fossil-fuel deposit originating from metamorphosed plant material [LCOTE]

coelacanth: A lobe-finned fish originating in the Paleozoic and presently living in deep seas [LCOTE]

coelenterate: Multicellular marine organisms, including jellyfish and corals [LCOTE]

comet: A celestial body believed to originate from a cloud of comets that surrounds the Sun and develops a long tail of gas and dust particles when traveling near the inner solar system [LCOTE]

conglomerate: A sedimentary rock composed of welded fine-grained and coarse-grained rock fragments [LCOTE]

conodont: A Paleozoic, toothlike fossil probably from an extinct marine vertebrate [LCOTE]

continental glacier: An ice sheet covering a portion of a continent [LCOTE]

continental drift: The concept that the continents drift across the surface of the Earth [LCOTE]

continental shelf: The offshore area of a continent in shallow sea [LCOTE]

continental slope: The transition from the continental margin to the deep-sea basin [LCOTE]

convection: A circular, vertical flow of a fluid medium by heating, from below; as materials are heated, they become less dense and rise, cool down, become more dense, and sink [LCOTE]

coprolite: Fossilized excrement, generally black or brown, used to determine the eating habits of animals [LCOTE]

coquina: A limestone comprised mostly of broken pieces of marine fossils

coral: A large group of shallow-water, bottom-dwelling marine invertebrates comprising reef-building colonies common in warm waters [LCOTE]

correlation: The tracing of equivalent rock exposures over distance usually with the aid of fossils [LCOTE]

craton: The ancient, stable interior region of a continent, usually composed of Precambrian rocks [LCOTE]

crinoid: An echinoderm with a flowerlike body atop a long stalk of calcite disks [LCOTE]

crossopterygian: Extinct Paleozoic fish thought to have given rise to terrestrial vertebrates [LCOTE]

crust: The outer layers of a planet's or moon's rocks [LCOTE]

crustacean: An arthropod characterized by two pairs of antenna-like appendages forward of the mouth and three pairs behind it, including shrimps, crabs, and lobsters [LCOTE]

danburite: a borosilicate of calcium, of a white to yellowish color, often occurring in fine crystals resembling topaz. CaB2(SiO4)2 [from Danbury, city in Connecticut, where it occurs + -ite] [AHDOS]

datolite: a silicate containing boron and calcium, found as glassy crystals in various colors. CaBSiO4(OH) [from Greek dateisthai to divide + English -ite] [AHDOS]

debouchure: or debouchment the mouth or outlet of a river or pass: Some rivers, like the Mississippi, combine all three stages from source to debouchure, being youthful in the upper course and old at the outlet, maturity prevailing midway. [AHDOS]

deflation: the process by whihc the wind sorts and moves sand, rock particles, etc. [AHDOS]

delta: the deposit of earth and sand, usually fanning out, that collects where a stream flows into a slower river, or into a lake or sea. – deltal: adj. of or having to do with a delta. [AHDOS]

dendrite: a mineral with a branching, treelike pattern, usually a manganese oxide; a crystallilne growth of branching form. – dendritic: adj. formed or marked like a dendrite, treelike. – dentritically: adv. [AHDOS]

denude: to lay (a rock, etc.) bare as by erosion. – denudant: n. any agent or agency causing denudation. – denudation: n. the process of denuding. [AHDOS]

deposit: a concentrated aggregate of one or more minerals, especially one of potential economic value; a mass of some mineral in rock or in the ground. [AHDOS]

deposition: the laying down of sediments by floodplains, glaciers, alluvial fans, etc. [AHDOS]

depression: a low place or hollow on a plain surface. [AHDOS]

desert: a dry, barren region that is usually sandy or rocky and without trees. – desertic: of or having to do with a desert or deserts. – desertification: the process of turning into arid land or desert. [AHDOS]

detritus: and accumulation of small fragments such as sand, silt, etc. worn away from rock. – detrital (de-TRI-tl), adj. composed of or involving detritus. [AHDOS]

Devonian: the fourth period of the Paleozoic era, after the Silurian and before the Mississippian, characterized by the appearance of amphibians, wingless insects, and forests; rocks formed during this period. [AHDOS]

diabase: a fine-grained, dark-colored, crystalline, granular igneous rock related to basalt and gabbro, consisting essentially of augite and calcite plagioclase feldspar; an altered form of basalt or dolerite. [AHDOS]

diagenesis: any modification in a sediment between its desposition and its metamorphism, including its conversion into rock. [AHDOS]

diamond: an isometric crystallized form of pure carbon, used as a precious stone and as an abrasive. The varieties used as gems are colorless. Diamond is the hardest natural substance known, ranking 10 on the Mohs scale. [AHDOS]

diapir: an anticlinalfold in which a mobile core, such as salt or gypsum, has pierced through the more brittle overlying rock. [AHDOS]

diaspore: a naative hydroxide of aluminum varying in color from white to violet, occuring in bauxite in scaly, crystalline masses. [AHDOS]

diastem: a minor break in sedimentary rocks, accompanied by little or no erosion. [AHDOS]

diastrophism: the action of the forces that have caused the deformation of the earth's crust, producing mountains, continents, etc. [AHDOS]

diatomite: a light, porous rock consissting of the fossil remains of diatoms, used as an abrasive, insulator, filter, etc. [AHDOS]

diatreme: a volcanic vent blasted through solid rock by exploding gases. [AHDOS]

dike: a long mass of igneous rock that was intruded into a crosscutting fissure in older rock; a discordant intrusive body of tabular rock. [AHDOS]

diluvial: of or having to do with a flood; made up of debris left by a flood. [AHDOS]

dinosaur: any of a large group if extinct terrestrial or amphibious reptiles that were chiefly herbivorous, had usually very long limbs and tails, and walked on two or four feet. [AHDOS]

dioptase: a translucent silicate of copper, found in green, hexagonal crystals. CuSiO2(OH)2 [AHDOS]

diorite: a coarse-grained igneous rock solidified far below the earth's surface and consisting essentially of hornblende and plagioclase containing sodium. [AHDOS]

dip: a downward slope of a stratum or vein. [AHDOS]

discontinuity: the boundary of a layer or formation at which marked changes in earthquake waves occur, such as Mohorovicic discontinuity. [AHDOS]

dolomite: a rock consisting mainly of calcium magnesium carbonate; the mineral, calcium and magnesium carbonate, that composes this rock. [AHDOS]

dome: a structure or formation in which the beds dip away approximately equally from a central point; any structure or formation resembling the dome of a building. [AHDOS]

drainage basin: the area drained by a stream and its tributaries. [AHDOS]

dripstone: deposits of calcium carbonate built up by dripping water in caves and forming stalactites and stalagmites. [AHDOS]

druse: a crust of small crystals lining the sides of a cavityin a rock. [AHDOS]

dune: a mound or ridge of loose sand heaped up by the wind. [AHDOS]


Ed resources
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Geologic time scale

Geology museums

Glossary of terms

Mineral identification

MOHS hardness scale

US National Parks

US State Fossils

US State Gems/Minerals

US State Parks


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