Earth Science, Geologic Time & Fossils, CEL-COS

Planet Earth has billions of years of history, from the time when it was an inhospitable ball of hot magma to when its surface stabilized into a variety of diverse zones capable of supporting many life-forms. Many are the species that lived through the various geologic eras and left a trace of their existence in the fossils that we study today. But Earth is never done settling, as we can see from the earthquakes, tsunamis, volcanic eruptions, and other phenomena manifested in Earth’s crust, oceans, and atmosphere.
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Earth Science, Geologic Time & Fossils Encyclopedia Articles By Title

Cellini’s halo
Cellini’s halo, bright white ring surrounding the shadow of the observer’s head on a dew-covered lawn with a low......
cementation
cementation, in geology, hardening and welding of clastic sediments (those formed from preexisting rock fragments)......
Cenozoic Era
Cenozoic Era, third of the major eras of Earth’s history, beginning about 66 million years ago and extending to......
Cephalaspis
Cephalaspis, extinct genus of very primitive, jawless, fishlike vertebrates found in Lower Devonian rocks (the......
cerargyrite
cerargyrite, gray, very heavy halide mineral composed of silver chloride (AgCl); it is an ore of silver. It forms......
Ceratites
Ceratites, extinct genus of cephalopods (whose modern members include the octopus, the squid, and the nautilus)......
ceratopsian
ceratopsian, any of a group of plant-eating dinosaurs from the Cretaceous Period (146 million to 66 million years......
Ceraurus
Ceraurus, genus of trilobites (extinct arthropods) found as fossils in rocks of Ordovician period (505 to 438 million......
cerussite
cerussite, lead carbonate (PbCO3), an important ore and common secondary mineral of lead. It is formed by the chemical......
chalcanthite
chalcanthite, a widespread sulfate mineral, naturally occurring hydrated copper sulfate, CuSO4·5H2O. It occurs......
chalcocite
chalcocite, sulfide mineral that is one of the most important ores of copper. Valuable occurrences include deposits......
chalcopyrite
chalcopyrite, the most common copper mineral, a copper and iron sulfide, and a very important copper ore. It typically......
Chalicotherium
Chalicotherium, genus of extinct perissodactyls, the order including the horse and rhinoceros. Fossil remains of......
Challenger Expedition
Challenger Expedition, prolonged oceanographic exploration cruise from Dec. 7, 1872, to May 26, 1876, covering......
Chamberlin, Thomas Chrowder
Thomas Chrowder Chamberlin was a U.S. geologist and educator who proposed the planetesimal hypothesis, which held......
Chapman, Sydney
Sydney Chapman was an English mathematician and physicist noted for his research in geophysics. Chapman was educated......
Charney, Jule Gregory
Jule Gregory Charney was an American meteorologist who contributed to the development of numerical weather prediction......
charnockite
charnockite, any member of a series of metamorphic rocks with variable chemical composition, first described from......
chatoyance
chatoyance, the property of some minerals to exhibit a wavy, luminous band with a silky lustre, reminiscent of......
Cheirolepis
Cheirolepis, extinct genus of primitive fishes whose fossils are found in European and North American rocks of......
chemical hydrology
chemical hydrology, subdivision of hydrology that deals with the chemical characteristics of the water on and beneath......
Chengjiang fossil site
Chengjiang fossil site, formation in China containing fossils dating to the Terreneuvian Epoch of the Cambrian......
Chernozem
Chernozem, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO).......
Chichester, Sir Francis
Sir Francis Chichester was an adventurer who in 1966–67 sailed around the world alone in a 55-foot sailing yacht,......
Chile earthquake of 1960
Chile earthquake of 1960, the largest earthquake recorded in the 20th century. Originating off the coast of southern......
Chile earthquake of 2010
Chile earthquake of 2010, severe earthquake that occurred on February 27, 2010, off the coast of south-central......
Chile saltpetre
Chile saltpetre, sodium nitrate, a deliquescent crystalline sodium salt that is found chiefly in northern Chile......
Chiricahua National Monument
Chiricahua National Monument, wilderness of unusual volcanic rock formations—tall and slender pinnacles crowded......
Chondrosteiformes
Chondrosteiformes, an extinct order of ray-finned saltwater fishes (class Actinopterygii) comprising a single family......
Chonetes
Chonetes, genus of extinct brachiopods, or lamp shells, found as fossils in marine rocks of Silurian to Permian......
Christchurch earthquakes of 2010–11
Christchurch earthquakes of 2010–11, series of tremors that occurred within and near the city of Christchurch,......
chromate mineral
chromate mineral, any member of a small group of rare inorganic compounds that have formed from the oxidation of......
chrysoberyl
chrysoberyl, gemstone, beryllium and aluminum oxide (BeAl2O4). A variety that is often cloudy, opalescent, and......
chrysocolla
chrysocolla, a silicate mineral, hydrated copper silicate, CuSiO3·2H2O, formed as a decomposition product of copper......
chrysotile
chrysotile, (Greek: “hair of gold”), fibrous variety of the magnesium silicate mineral serpentine; chrysotile is......
cinnabar
cinnabar, mercury sulfide (HgS), the chief ore mineral of mercury. It is commonly encountered with pyrite, marcasite,......
Cizin
Cizin, (Mayan: “Stinking One”), Mayan earthquake god and god of death, ruler of the subterranean land of the dead.......
Cladoselache
Cladoselache, genus of extinct sharks, known from fossilized remains in Upper Devonian rocks (formed 385–359 million......
Clarke, Edward Daniel
Edward Daniel Clarke was an English mineralogist and traveler who amassed valuable collections of minerals, manuscripts,......
clay
clay, soil particles the diameters of which are less than 0.005 millimetre; also a rock that is composed essentially......
clay mineralogy
clay mineralogy, the scientific discipline concerned with all aspects of clay minerals, including their properties,......
claystone
claystone, hardened clay. Some geologists further restrict the term to a sedimentary rock that is composed primarily......
clear-air turbulence
clear-air turbulence (CAT), erratic air currents that occur in cloudless air between altitudes of 6,000 and 15,000......
cleavage
cleavage, tendency of a crystalline substance to split into fragments bounded by plane surfaces. Although cleavage......
Cleve, Per Teodor
Per Teodor Cleve was a Swedish chemist who discovered the elements holmium and thulium. Cleve became assistant......
Clidastes
Clidastes, (genus Clidastes), extinct ancient marine lizards belonging to a family of reptiles called mosasaurs.......
Climacograptus
Climacograptus, genus of graptolites, extinct colonial animals related to the primitive chordates, found as fossils......
climate
climate, conditions of the atmosphere at a particular location over a long period of time; it is the long-term......
climate classification
climate classification, the formalization of systems that recognize, clarify, and simplify climatic similarities......
climate stripes
climate stripes, any graphical representation of historical temperature data that appears as a series of colored......
climatic map
climatic map, chart that shows the geographic distribution of the monthly or annual average values of climatic......
Climatius
Climatius, genus of extinct, primitive jawed vertebrates common as fossils in Devonian rocks in Europe and North......
climatology
climatology, branch of the atmospheric sciences concerned with both the description of climate and the analysis......
Clonograptus
Clonograptus, genus of graptolites (extinct, small floating colonial animals related to the primitive chordates),......
Cloos, Hans
Hans Cloos was a German geologist who was a pioneer in the study of granite tectonics (the deformation of crystalline......
cloud
cloud, any visible mass of water droplets, ice crystals, or a mixture of both that is suspended in the air, usually......
cloud seeding
cloud seeding, deliberate introduction into clouds of various substances that act as condensation nuclei or ice......
cloud whitening
cloud whitening, untested geoengineering technique designed to increase the reflectance of Earth’s cloud cover......
cloudburst
cloudburst, a sudden, very heavy rainfall, usually local in nature and of brief duration. Most so-called cloudbursts......
Clüver, Philipp
Philipp Clüver was a German geographer, a principal figure in the revival of geographic learning in Europe and......
coal ball
coal ball, a lump of petrified plant matter, frequently spheroid, found in coal seams of the Upper Carboniferous......
Coatlicue
Coatlicue, Aztec earth goddess, symbol of the earth as both creator and destroyer, mother of the gods and mortals.......
cobaltite
cobaltite, a cobalt sulfoarsenide mineral in which iron commonly replaces part of the cobalt [(Co,Fe)AsS], that......
coccolith
coccolith, minute calcium carbonate platelet or ring secreted by certain organisms (coccolithophores, classed either......
cohenite
cohenite, an iron nickel carbide mineral with some cobalt [(Fe,Ni,Co)3C] that occurs as an accessory constituent......
cold front
cold front, leading edge of an advancing mass of relatively cold air. In middle and higher latitudes of both hemispheres......
colemanite
colemanite, borate mineral, hydrated calcium borate (Ca2B6O11·5H2O) that was the principal source of borax until......
collophane
collophane, massive cryptocrystalline apatite, composing the bulk of fossil bone and phosphate rock, commonly carbonate-containing......
Colorado National Monument
Colorado National Monument, scenic wilderness area in west-central Colorado, U.S., just west of the city of Grand......
colour index
colour index, in igneous petrology, the sum of the volume percentages of the coloured, or dark, minerals contained......
columbite
columbite, hard, black (often iridescent), heavy oxide mineral of iron, manganese, and niobium, (Fe, Mn)Nb2O6.......
compaction
compaction, in geology, decrease of the volume of a fixed mass of sediment from any cause, commonly from continual......
Composita
Composita, genus of extinct brachiopods, or lamp shells, found as fossils in marine rocks of the Carboniferous......
Conchidium
Conchidium, genus of extinct brachiopods, or lamp shells, that is a valuable index fossil in marine rocks of the......
condensation nucleus
condensation nucleus, tiny suspended particle, either solid or liquid, upon which water vapour condensation begins......
Condylarthra
Condylarthra, extinct group of mammals that includes the ancestral forms of later, more-advanced ungulates (hoofed......
Confuciusornis
Confuciusornis, genus of extinct crow-sized birds that lived during the Late Jurassic and Early Cretaceous (roughly......
conglomerate
conglomerate, in petrology, lithified sedimentary rock consisting of rounded fragments greater than 2 millimetres......
conodont
conodont, minute toothlike fossil composed of the mineral apatite (calcium phosphate); conodonts are among the......
Constellaria
Constellaria, genus of extinct bryozoans (small colonial animals that produce a skeletal framework of calcium carbonate)......
continent
continent, one of the larger continuous masses of land, namely, Asia, Africa, North America, South America, Antarctica,......
continental air mass
continental air mass, vast body of air that forms over the interior of a continent, excluding mountainous areas.......
continental drift
continental drift, large-scale horizontal movements of continents relative to one another and to the ocean basins......
continental subarctic climate
continental subarctic climate, major climate type of the Köppen classification dominated by the winter season,......
continentality
continentality, a measure of the difference between continental and marine climates characterized by the increased......
contrail
contrail, streamer of cloud sometimes observed behind an airplane flying in clear cold humid air. A contrail forms......
Conybeare, William Daniel
William Daniel Conybeare was an English geologist and paleontologist, known for his classic work on the stratigraphy......
Cope, Edward Drinker
Edward Drinker Cope was a paleontologist who discovered approximately a thousand species of extinct vertebrates......
Copernicus, Nicolaus
Nicolaus Copernicus Polish astronomer who proposed that the planets have the Sun as the fixed point to which their......
copper
copper (Cu), chemical element, a reddish, extremely ductile metal of Group 11 (Ib) of the periodic table that is......
coprolite
coprolite, the fossilized excrement of animals. The English geologist William Buckland coined the term in 1835......
Cordaitales
Cordaitales, an order of coniferophytes (phylum, sometimes division, Coniferophyta), fossil plants dominant during......
Cordaites
Cordaites, extinct genus of seed plants with leathery, strap-shaped leaves from the Pennsylvanian Subperiod (318......
cordierite
cordierite, blue silicate mineral that occurs as crystals or grains in igneous rocks. It typically occurs in thermally......
Cordilleran Geosyncline
Cordilleran Geosyncline, a linear trough in the Earth’s crust in which rocks of Late Precambrian to Mesozoic age......
Coryphodon
Coryphodon, genus of extinct primitive hoofed mammals known from Late Paleocene and Early Eocene deposits (those......
Cosmas
Cosmas was a merchant, traveler, theologian, and geographer whose treatise Topographia Christiana (c. 535–547;......

Earth Science, Geologic Time & Fossils Encyclopedia Articles By Title