Earth Science, Geologic Time & Fossils, MON-OXI
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.
Earth Science, Geologic Time & Fossils Encyclopedia Articles By Title
montebrasite, phosphate mineral (LiAl(PO4)(OH,F)) similar to amblygonite...
monzonite, intrusive igneous rock that contains abundant and approximately equal amounts of plagioclase and potash......
Moon, Earth’s sole natural satellite and nearest large celestial body. Known since prehistoric times, it is the......
Raymond Cecil Moore was an American paleontologist known for his work on Paleozoic crinoids, bryozoans, and corals......
Morganucodon, extinct genus of tiny mammals known from fossils dated to the Triassic-Jurassic boundary (approximately......
Morocco earthquake of 2023, severe earthquake that struck near the town of Oukaïmedene in western Morocco on September......
The Morocco earthquake of 2023 was a magnitude-6.8 temblor that struck central Morocco on September 8, 2023, at......
Moropus, extinct genus of the chalicotheres, a group of very unusual perissodactyls (“odd-toed” ungulates) related......
moroxite, clear blue variety of the mineral apatite...
morphogenetic region, theoretical area devised by geomorphologists to relate climate, geomorphic processes, and......
morphometric analysis, quantitative description and analysis of landforms as practiced in geomorphology that may......
Morrison Formation, series of sedimentary rocks deposited during the Jurassic Period in western North America,......
Jedidiah Morse was an American Congregational minister and geographer, who was the author of the first textbook......
mosasaur, (family Mosasauridae), extinct group of aquatic lizards that attained a high degree of adaptation to......
Moschops, extinct genus of mammal-like reptiles (Therapsida) found as fossils in rocks of Permian age (299 million......
mottramite, vanadate mineral (PbCu(VO4)(OH)) similar to descloizite...
Mucrospirifer, genus of extinct brachiopods (lamp shells) found as fossils in Middle and Upper Devonian marine......
mud volcano, mound of mud heaved up through overlying sediments. The craters are usually shallow and may intermittently......
mudstone, sedimentary rock composed primarily of clay- or silt-sized particles (less than 0.063 mm [0.0025 inch]......
multiringed basin, any of a class of geologic features that have been observed on various planets and satellites......
multituberculate, any member of an extinct group of small, superficially rodentlike mammals that existed from about......
Walter Munk was an Austrian-born American oceanographer whose pioneering studies of ocean currents and wave propagation......
Sir Roderick Impey Murchison was a geologist who first established the geologic sequence of Early Paleozoic strata......
Sir John Murray was a Scottish Canadian naturalist and one of the founders of oceanography, whose particular interests......
Mylodon, extinct genus of ground sloth found as fossils in South American deposits of the Pleistocene Epoch (2.6......
Myophoria, genus of extinct clams found as fossils in Triassic rocks. It is readily identified by its distinctive......
myrmekite, irregular, wormy penetration by quartz in plagioclase feldspar; these wartlike, wormlike, or fingerlike......
Sophus Otto Müller was a Danish archaeologist who, during the late 19th century, discovered the first of the Neolithic......
Sebastian Münster was a German cartographer, cosmographer, and Hebrew scholar whose Cosmographia (1544; “Cosmography”)......
nahcolite (NaHCO3), colourless to white carbonate mineral, a naturally occurring sodium bicarbonate. (The name......
Fridtjof Nansen was a Norwegian explorer, oceanographer, statesman, and humanitarian who led a number of expeditions......
nappe, in geology, large body or sheet of rock that has been moved a distance of about 2 km (1.2 miles) or more......
National Geographic Magazine, monthly magazine of geography, archaeology, anthropology, and exploration, providing......
National Geographic Society, American scientific society founded (1888) in Washington, D.C., by a small group of......
National Oceanic and Atmospheric Administration (NOAA), U.S. governmental agency established in 1970 within the......
native element, any of a number of chemical elements that may occur in nature uncombined with other elements. The......
Nazca Plate, major tectonic plate composed of oceanic crust underneath the Pacific Ocean adjacent to the western......
Neanderthal, (Homo neanderthalensis, Homo sapiens neanderthalensis), member of a group of archaic humans who emerged......
neap tide, tide of minimal range occurring near the time when the Moon and the Sun are in quadrature. This condition......
Neogene Period, the second of three divisions of the Cenozoic Era. The Neogene Period encompasses the interval......
neoprioniodiform, conodont, or small toothlike phosphatic fossil of uncertain affinity, that is characterized by......
Neospirifer, genus of extinct brachiopods (lamp shells) found as fossils in Late Carboniferous to Permian marine......
Nepal earthquake of 2015, severe earthquake that struck near the city of Kathmandu in central Nepal on April 25,......
nepheline syenite, medium- to coarse-grained intrusive igneous rock, a member of the alkali-syenite group (see......
nephelinite, silica-poor (mafic) lava that contains nepheline and pyroxene and is usually completely crystallized.......
nesosilicate, compound with a structure in which independent silicate tetrahedrons (each consisting of a central......
New Madrid earthquakes of 1811–12, series of three large earthquakes that occurred near New Madrid, Missouri, between......
New Madrid Seismic Zone (NMSZ), region of poorly understood, deep-seated faults in Earth’s crust that zigzag southwest-northeast......
niccolite, an ore mineral of nickel, nickel arsenide (NiAs). It is commonly found associated with other nickel......
nickel–iron, very rare native alloy of nickel and iron that contains between 24 and 77 percent nickel. It occurs......
nightglow, weak, steady light emanating from the whole night sky. See...
Nitisol, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO).......
nitrate and iodate minerals, small group of naturally occurring inorganic compounds that are practically confined......
noctilucent cloud, rare cloud form, probably composed of ice crystals and dust from meteor smoke, that occurs at......
nodule, rounded mineral concretion that is distinct from, and may be separated from, the formation in which it......
normal fault, type of fault in which lengthening, or extension, of a portion of Earth’s crust causes a block of......
North America, third largest of the world’s continents, lying for the most part between the Arctic Circle and the......
- Introduction
- Geology, Plate Tectonics, Erosion
- Geology, Forests, Lakes
- Tectonics, Evolution, Geology
- Prehistoric, Geology, Plate Tectonics
- Late Mesozoic, Cenozoic, Geology
- Glaciation, Migration, Megafauna
- Marginal Mountains, Geology, Climate
- Lowlands, Plains, Coastlines
- Lakes, Rivers, Coastlines
- Grassland, Desert, Tundra
- Air Masses, Climate, Weather
- Climate, Geography, Wildlife
- Boreal Forest, Wildlife, Ecosystems
- Prairies, Steppes, Savannas
- Indigenous, Settlers, Immigration
- Dispossession, Indigenous, Colonization
- African Heritage, Culture, History
- Economy, Trade, Resources
- Coal Deposits, Mining, Geology
- Wildlife, Flora, Fauna
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- Hydroelectricity, Rivers, Dams
- Trade, Resources, Markets
- Transportation, Infrastructure, Trade
North Pole, the northern end of Earth’s axis, lying in the Arctic Ocean, about 450 miles (725 km) north of Greenland.......
northern lights, luminous atmospheric display visible in the Northern Hemisphere. See...
Northridge earthquake of 1994, earthquake that struck the densely populated San Fernando Valley in southern California,......
About 50,000 earthquakes large enough to be noticed without the aid of instruments occur annually worldwide. Some......
Notharctus, extinct genus of small primates (family Adapidae) that shares many similarities with modern lemurs,......
Nothosaurus, (genus Nothosaurus), marine reptiles found as fossils from the Triassic Period (251 million to 200......
Notoungulata, extinct group of hoofed mammals found as fossils, mostly in South America, although the oldest forms......
nuclear winter, the environmental devastation that certain scientists contend would probably result from the hundreds......
nummulite, any of the thousands of extinct species of relatively large, lens-shaped foraminifers (single-celled......
Pedro Nunes was a mathematician, geographer, and the chief figure in Portuguese nautical science, noted for his......
Obolus, genus of extinct brachiopod, or lamp shell, of the Cambrian Period (from 542 million to 488 million years......
obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes.......
obsidian–hydration–rind dating, method of age determination of obsidian (black volcanic glass) that makes use of......
ocean, continuous body of salt water that is contained in enormous basins on Earth’s surface. When viewed from......
ocean acidification, the worldwide reduction in the pH of seawater as a consequence of the absorption of large......
ocean current, stream made up of horizontal and vertical components of the circulation system of ocean waters that......
ocean fertilization, untested geoengineering technique designed to increase the uptake of carbon dioxide (CO2)......
ocean warming, the absorption of surplus heat attributed to global warming by water in the oceans. Ocean warming......
oceanography, scientific discipline concerned with all aspects of the world’s oceans and seas, including their......
Odessa Meteor Crater, shallow, cone-shaped impact crater in the High Plains just southwest of Odessa, Texas, U.S.,......
odontolite, fossil bone or tooth that consists of the phosphate mineral apatite (q.v.) coloured blue by vivianite.......
Richard Dixon Oldham was a British geologist and seismologist who discovered evidence for the existence of the......
Olenellus, genus of trilobites (extinct arthropods) common in but restricted to Early Cambrian rocks (542 million......
olivine, any member of a group of common magnesium, iron silicate minerals. Olivines are an important rock-forming......
Jean-Baptiste-Julien d’ Omalius d’Halloy was a Belgian geologist who was an early proponent of evolution. D’Omalius......
Albert Oppel was a German geologist and paleontologist, who was one of the most important early stratigraphers.......
Alcide Dessalines d’ Orbigny was the founder of the science of micropaleontology. During eight years of travel......
Ordovician Period, in geologic time, the second period of the Paleozoic Era. It began 485.4 million years ago,......
oreodont, any member of a diverse group of extinct herbivorous North American artiodactyls (even-toed ungulates)......
Oreopithecus, extinct genus of primates found as fossils in Late Miocene deposits in East Africa and Early Pliocene......
ornithischian, any member of the large taxonomic group of herbivorous dinosaurs comprising Triceratops and all......
Ornithomimus, (genus Ornithomimus), ostrichlike feathered dinosaurs found as fossils in Mongolian, European, and......
ornithopod, any member of the group of ornithischian dinosaurs characterized by a two-legged (bipedal) stance,......
orographic precipitation, rain, snow, or other precipitation produced when moist air is lifted as it moves over......
orpiment, the transparent yellow mineral arsenic sulfide (As2S3), formed as a hot-springs deposit, an alteration......
orthopyroxene granite, member of the charnockite (q.v.) series of metamorphic...
Henry Fairfield Osborn was an American paleontologist, eugenicist, and museum administrator who greatly influenced......
Osteolepis, extinct genus of lobe-finned fishes from the Late Devonian; Osteolepiformes is a variation of this......
John Ostrom was an American paleontologist who popularized the theory that many species of dinosaurs were warm-blooded......
Ouachita Geosyncline, a linear trough in the Earth’s crust in which rocks of the Paleozoic Era (from 542 million......
Richard Owen was a British anatomist and paleontologist who is remembered for his contributions to the study of......
oxide mineral, any naturally occurring inorganic compound with a structure based on close-packed oxygen atoms in......
Oxisol, one of the 12 soil orders in the U.S. Soil Taxonomy. Oxisols form principally in humid tropical zones under......