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  • subdivision (geography)

    servitude: In subdivisions and planned developments, burdens and benefits are often reciprocal. Each lot or unit is burdened by servitudes for the benefit of all the others. In most U.S. states, if a project developer represents to prospective purchasers, either explicitly or implicitly, that all the property…

  • Subdivisions du Paléolithique supérieur et leur signification, Les (work by Breuil)

    Henri Breuil: In particular, his paper “Les Subdivisions du Paléolithique supérieur et leur signification” (1912; “The Subdivisions of the Upper Paleolithic and Their Meaning”) established for the period a classification system that is of enduring value. In his attempt to explain the significance of these Ice Age objects, he developed a…

  • subdominant (music)

    Subdominant, in Western music, the fourth note of the diatonic (seven-note) scale (e.g., F in a scale based on C), so named because it lies at the interval of a fifth below the tonic; by contrast, the dominant lies at the fifth above the tonic (e.g., G in a scale based on

  • subduction (geology)

    Africa: General considerations: …the present Nile River, by subduction processes identical to those observed today. (Subduction involves the descent of the edge of one lithospheric plate beneath that of another where two such plates collide.)

  • subduction volcano (geology)

    volcano: Subduction volcanoes: As an oceanic plate is subducted beneath a continental plate, seafloor sediments rich in water and carbon dioxide are carried beneath the overriding plate. These compounds may act as fluxes, reducing the melting temperature of magma. Although the process is not clearly understood,…

  • subduction zone (geology)

    Subduction zone, oceanic trench area marginal to a continent in which, according to the theory of plate tectonics, older and denser seafloor underthrusts the continental mass, dragging downward into the Earth’s upper mantle the accumulated trench sediments. The subduction zone, accordingly, is the

  • subdural hematoma (medicine)

    Subdural hematoma, bleeding into the space between the brain and its outermost protective covering, the dura. It typically results when a traumatic force applied to the head creates significant fast-changing velocities of the contents inside the skull. The expanding hemorrhage can increase the

  • subdural space (anatomy)

    meninges: …the arachnoid by the narrow subdural space, which is filled with fluid. In a few places, the subdural space is absent, and the arachnoid is intimately fused with the dura mater. The most important area of fusion between these two meninges is in the walls of the large venous channels…

  • Subei (region, China)

    Jiangsu: Land: …“South of the River”) and Subei (“North [Jiang]su”). Jiangnan is fertile and well-watered, famed for its silk and handicrafts, and very densely populated and industrialized. The cities of Suzhou (Soochow), Nanjing, and Wuxi, as well as Shanghai, are all located in this region. Shanghai is situated at the mouth of…

  • Subei Canal (canal, China)

    Subei Canal, canal in Jiangsu province, eastern China, designed to provide a direct outlet to the sea for the waters of the Huai River, which discharged near the mouth of the Guan River. In the late 12th century ad the Huang He (Yellow River) changed its course to discharge south of the Shandong

  • Subei Guangai Zong Qu (canal, China)

    Subei Canal, canal in Jiangsu province, eastern China, designed to provide a direct outlet to the sea for the waters of the Huai River, which discharged near the mouth of the Guan River. In the late 12th century ad the Huang He (Yellow River) changed its course to discharge south of the Shandong

  • suberakashi (hairdressing)

    dress: Japan: …an elaborate coiffure known as suberakashi, and affixed directly over the forehead are special hair ornaments consisting of a lacquered, gold-sprinkled comb surmounted by a gold lacquered chrysanthemum crest.

  • suberin (biochemistry)

    angiosperm: Dermal tissue: …inner walls are lined with suberin, a fatty substance that is highly impermeable to gases and water (which is why cork is used to stop wine bottles). The walls of cork cells may also contain lignin.

  • Suberites domuncula (species of sponge)

    sponge: Associations with other organisms: …is that of the sponge Suberites domuncula and hermit crabs, which live in the shells of gastropod mollusks. The advantage to the sponge is that it is carried by the mollusk; the hermit crab gains protection not only by living in the shell of the mollusk but also through the…

  • subfornical organ (physiology)

    human nervous system: Vasopressin and cardiovascular regulation: Another circumventricular organ, called the subfornical organ, lies in the dorsal part of the third ventricle; it is particularly sensitive to hormones such as angiotensin II and signals that changes are needed for the regulation of salt and water balance. Both regions project directly to vasopressin-producing hypothalamic neurons. The area…

  • subgiant star (astronomy)

    star: Hertzsprung-Russell diagram: Subgiants are stars that are redder and larger than main-sequence stars of the same luminosity. Many of the best-known examples are found in close binary systems where conditions favour their detection.

  • subglacial lake

    Whillans Ice Stream: Subglacial lakes: Multiple subglacial lakes exist beneath Whillans Ice Stream, where they form part of an interconnected system of channels and lakes that underlies Whillans and neighbouring ice streams. Beneath Whillans Ice Stream, fluctuations in water movement through the system cause repeated filling and draining…

  • Subglacial Lake Vostok (lake, Antarctica)

    Lake Vostok, largest lake in Antarctica. Located approximately 2.5 miles (4 km) beneath Russia’s Vostok Station on the East Antarctic Ice Sheet (EAIS), the water body is also the largest subglacial lake known. Running more than 150 miles (about 240 km) long with a maximum width of about 31 miles

  • subglacial volcanism (geology)

    volcano: Determinants of size and shape: Subglacial volcanism produces landforms that are dramatically different from those produced by subaerial volcanism. This is particularly apparent in Iceland, where glaciers covered the entire island 15,000 years ago, and large ice caps still cover extensive areas today. Fissure eruptions beneath the ice form steep…

  • subgraywacke (rock)

    Subgraywacke, dark-coloured sedimentary rock that contains from 65 to 95 percent free quartz, in grains 0.06 to 2 mm in diameter, held together by a matrix with a low mud content and often a high carbonate content. Some geologists favour a definition of graywacke (q.v.) that permits no more than

  • ?ub? al-a?shā (work compiled by al-Qalqashandī)

    encyclopaedia: The Arab world: …more important and well-organized encyclopaedia, ?ub? al-a?shā (“The Dawn for the Blind”), that covered geography, political history, natural history, zoology, mineralogy, cosmography, and time measurement. Al-Ibshīhī (1388–c. 1446) compiled a very individual encyclopaedia, the Musta?raf fī kull fann musta?raf (“A Quest for Attainment in Each Fine Art”), that covered the…

  • sub?a (Muslim prayer beads)

    Sub?ah, string of Muslim prayer beads whose units (100, 25, or 33) represent the names of God. As the beads (made of wood, bone, or precious stones) are touched one by one, Muslims may recite any of numerous formulas, the most common being “Glory to Allāh.” But because prayer may also be recited

  • Subhadra (Hindu deity)

    Jagannatha: …Balabhadra (Balarama), and his sister Subhadra. Modern representations made in Puri of the 10 avatars (incarnations) of Vishnu often show Jagannatha as one of the 10 in place of the more usually accepted Buddha.

  • sub?ah (Muslim prayer beads)

    Sub?ah, string of Muslim prayer beads whose units (100, 25, or 33) represent the names of God. As the beads (made of wood, bone, or precious stones) are touched one by one, Muslims may recite any of numerous formulas, the most common being “Glory to Allāh.” But because prayer may also be recited

  • subhā?ita (literature genre)

    South Asian arts: The short lyric: Authors of subhā?itas often collected them themselves, the favourite form being that of the ?ataka (“century” of verses), in which 100 short lyrics on a common theme were strung together. Mention has been made of Hāla’s Sattasaī (“The Seven Hundred,” consisting of lyrics in the Māhārā??rī dialect).…

  • subhedral crystal (geology)

    igneous rock: Fabric: …euhedral or panidiomorphic (fully crystal-faced), subhedral or hypidiomorphic (partly faced), or anhedral or allotriomorphic (no external crystal faces). Quite apart from the presence or absence of crystal faces, the shape, or habit, of individual mineral grains is described by such terms as equant, tabular, platy, elongate, fibrous, rodlike, lathlike, needlelike,…

  • Subhuman Redneck Poems (poetry by Murray)

    Les Murray: Subhuman Redneck Poems (1996) brings to the fore Murray’s ever-present disdain for Western intellectual attitudes; many critics found his satirical assaults unbalanced. In Fredy Neptune (1999) Murray presented a verse narrative of the misfortunes of a German Australian sailor during World War I. Later collections…

  • Subiaco (Italy)

    Subiaco, town, Lazio (Latium) regione, central Italy. It lies along the Aniene River, 1,345 feet (410 m) above sea level, about 45 miles (73 km) east of Rome. Its ancient name recalls its position below three small lakes where the emperor Nero built a villa. An inundation destroyed the lakes in

  • Subiaco (typeface)

    typography: The private-press movement: …types for his own use: Subiaco, based upon Sweynheim’s and Pannartz’ semiroman of the 1460s, and Ptolemy, based upon a late 15th-century German model. The Ashendene Press books, like those of Morris, were often illustrated with wood engravings, and many had coloured initials.

  • Subic Bay (bay, Philippines)

    Subic Bay, embayment of the South China Sea, southwestern Luzon, Philippines. The bay is located 35 miles (55 km) northwest of the mouth of Manila Bay and extends northward into the Luzon coastline. Rice, corn (maize), and bananas are grown in the area, and there are secondary forests around the

  • Subic Bay Naval Station (United States military base, Philippines)

    Subic Bay: …States operated a naval base, Subic Bay Naval Station, on the southeast coast of the bay, the largest naval installation in the Philippines. The area suffered heavy damage during World War II; it was taken by the Japanese in 1942 and retaken by Allied forces in 1944. Its proximity to…

  • Subida al amor (poetry by Bouso?o)

    Carlos Bouso?o: …his first volume of poetry, Subida al amor (“Ascent to Love”), which deals with struggles for religious faith. In 1946 he went to Mexico and then to the United States to teach literature at Wellesley College (Massachusetts). In 1948 he returned to Spain and took a doctorate at the University…

  • subidor (drum)

    Latin American dance: Puerto Rico: …challenge or converse with the subidor (high-pitched drum). The more equally matched in skill that the drummer and dancer are, the more intricate and satisfying the bomba will be. The spectators add their voices to the chorus and wait their turn to enter as dancers. In many respects the bomba…

  • subimago (biology)

    mayfly: Life cycle: …a winged form, called the subimago, or dun, emerges. The subimago flies from the surface of the water to some sheltered resting place nearby. After an interval lasting a few minutes to several days, but usually overnight, the skin is shed for the last time, and the imago, or adult…

  • subincision (ritual practice)

    Australian Aboriginal peoples: Socialization: Subincision (incisura of the urethra) was especially significant in its association with secret-sacred ritual. Other rites included piercing of the nasal septum, tooth pulling (in New South Wales this was central in initiation), and the blood rite, which involved bloodletting from an arm vein or…

  • subinfeudation (law)

    vassal: …they obtained the right to subinfeudate—that is, to become lords themselves by granting parts of their fiefs to vassals of their own. If a vassal died without heir or committed a felony, his fief went back to the lord (see escheat).

  • Subirà, Margarita Xirgu i (Spanish actress)

    Margarita Xirgu, Catalan actress and producer whose greatest contribution was her advancement of the plays of Federico García Lorca. Xirgu made her professional debut in Barcelona in 1906 and five years later joined the Teatro Principal. She made her first appearance in Madrid in 1914, performing

  • subirrigation

    horticulture: Water management: Subirrigation is the distribution of water to soil below the surface; it provides moisture to crops by upward capillary action. Trickle irrigation involves the slow release of water to each plant through small plastic tubes. This technique is adapted both to field and to greenhouse…

  • subject (logic)

    history of logic: Categorical forms: …negative quantifier “no”), (2) a subject, (3) a copula, (4) perhaps a negation (“not”), (5) a predicate. Propositions analyzable in this way were later called categorical propositions and fall into one or another of the following forms:

  • subject (grammar)

    Uralic languages: Verb inflections: The widespread use of separate subjective and objective conjugations among the Uralic languages (as in Mordvin, Ugric, and Samoyedic) are the result of an original system for singling out the subject or object for emphasis (focus), and not simply a device for object–verb agreement (similar to subject agreement). For example,…

  • subject (music)

    fugue: Elements of the fugue: …which the principal theme, or subject, is stated successively in each of the constituent voices or parts. The first statement of the subject is in one voice alone. While this voice continues, the second statement enters, transposed to the key of the dominant (the fifth degree of the scale), and…

  • subject catalog (library science)

    library: Cataloging by author and subject: …by the development of a subject catalog.

  • subject collection (library)

    book collecting: Styles of collecting: The subject collection could range from fields as sweeping as classics or American literature to books on chess, coffee, prizefighting, detective fiction, or the development of nuclear energy. Two collections formed by tobacco businessman George Arents and now in the New York Public Library illustrate the…

  • subject matter (art)

    painting: Devotional: The range and interpretation of subjects in different forms of devotional painting express a particular attitude to the relationship between man and God. Early Christian and Buddhist murals, for example, portrayed an all-powerful, remote, and mysterious being, painted as a flat, formalized head or figure whose stern gaze dominated the…

  • Subject of the Artist (art school)

    Barnett Newman: …he cofounded the school called “Subject of the Artist” (1948), which held open sessions and lectures for other artists.

  • subject political culture (political science)

    political culture: In a subject political culture, the citizens see themselves not as participants in the political process but as subjects of the government. In a participant political culture, the citizens believe both that they can contribute to the system and that they are affected by it. Almond and…

  • Subject Was Roses, The (film by Grosbard [1968])

    Jack Albertson: …supporting actor in the 1968 motion-picture version of that play, two Emmy Awards (1975 and 1976) for his portrayal of the cranky gas station–garage owner in the television series Chico and the Man, and another Emmy for a guest appearance on the Cher show in 1975. His last theatrical motion…

  • Subjection of Women, The (work by Mill)

    John Stuart Mill: The later years: …and in 1869 he published The Subjection of Women (written 1861), the classical theoretical statement of the case for woman suffrage. His last public activity was concerned with the starting of the Land Tenure Reform Association, for which he wrote in The Examiner and made a public speech a few…

  • subjective fundamental (physics)

    sound: The ear as spectrum analyzer: This effect, known as the missing fundamental, subjective fundamental, or periodicity pitch, is used by the ear to create the fundamental in sound radiating from a small loudspeaker that is not capable of providing low frequencies.

  • subjective idealism (philosophy)

    Subjective idealism, a philosophy based on the premise that nothing exists except minds and spirits and their perceptions or ideas. A person experiences material things, but their existence is not independent of the perceiving mind; material things are thus mere perceptions. The reality of the

  • subjective probability (probability)

    probability theory: An alternative interpretation of probability: …to say that someone has subjective probability p that a proposition is true means that for any integers r and b with r/(r + b) < p, if that individual is offered an opportunity to bet the same amount on the truth of the proposition or on “red in a…

  • Subjective Spirit (Hegelianism)

    Western philosophy: The idealism of Fichte, Schelling, and Hegel: Therefore, what began in Hegel as a metaphysics of the Absolute ended by becoming a total philosophy of human…

  • subjective tinnitus (physiology)

    tinnitus: …are two types of tinnitus: subjective, which is the most common form, and objective, which is relatively rare. In subjective tinnitus, only the person with the condition can hear the noise. In objective tinnitus, a physician can detect the ringing, buzzing, or clicking sound.

  • subjective tone (acoustics)

    Combination tone, in musical acoustics, faint tone produced in the inner ear by two simultaneously sounded musical tones. Because such tones are caused by the ear rather than by the external source of the sound, they are sometimes called subjective, or resultant, tones. There are two varieties:

  • subjectivism (philosophy)

    Western philosophy: The rationalism of Descartes: From the indubitability of the self, Descartes inferred the existence of a perfect God; and, from the fact that a perfect being is incapable of falsification or deception, he concluded that the ideas about the physical world that God has implanted in human beings…

  • Subjects of Desire: Hegelian Reflections in Twentieth-Century France (work by Butler)

    Judith Butler: Butler’s first book, Subjects of Desire: Hegelian Reflections in Twentieth-Century France (1987), a revised version of her doctoral dissertation, was a discussion of the concept of desire as it figures in G.W.F. Hegel’s Phenomenology of Spirit and its subsequent interpretations by various 20th-century French philosophers.

  • subjunctive mood (grammar)

    mood: indicative, the imperative, and the subjunctive. The indicative is generally used for factual or neutral situations, as in English “John did his work” and Spanish “Juan hizo su trabajo.” The imperative conveys commands or requests—for example, “Do your work.” It is distinguished by the absence of an explicit subject, the…

  • Sublaqueum (Italy)

    Subiaco, town, Lazio (Latium) regione, central Italy. It lies along the Aniene River, 1,345 feet (410 m) above sea level, about 45 miles (73 km) east of Rome. Its ancient name recalls its position below three small lakes where the emperor Nero built a villa. An inundation destroyed the lakes in

  • Sublett, John William (American dancer)

    tap dance: Vaudeville: John Bubbles, for instance, has gone down in history as the “Father of Rhythm Tap.” Though he may not have been the very first tap dancer to use the heel tap to push rhythm from the 1920s jazz beat to the 1930s swing beat, he…

  • sublevel caving

    mining: Sublevel caving: This method owes the first part of its name to the fact that work is carried out on many intermediate levels (that is, sublevels) between the main levels. The second half of the name derives from the caving of the hanging wall and…

  • sublevel stoping

    mining: Blasthole stoping: In sublevel stoping, shorter blastholes are drilled from sublevels located at shorter vertical intervals along the vertical stope. A fairly typical layout is shown in the figure. In vertical retreat mining the stope does not take the shape of a vertical slot. Instead, the trough serves…

  • sublimation (psychology)

    defense mechanism: Sublimation is the diversion or deflection of instinctual drives, usually sexual ones, into noninstinctual channels. Psychoanalytic theory holds that the energy invested in sexual impulses can be shifted to the pursuit of more acceptable and even socially valuable achievements, such as artistic or scientific endeavours.…

  • sublimation (phase change)

    Sublimation, in physics, conversion of a substance from the solid to the gaseous state without its becoming liquid. An example is the vaporization of frozen carbon dioxide (dry ice) at ordinary atmospheric pressure and temperature. The phenomenon is the result of vapour pressure and temperature

  • sublimation curve (physics)

    liquid: Phase diagram of a pure substance: …triple point is called the sublimation curve. It represents the equilibrium between solid and gas, and when the sublimation curve is crossed, the substance changes directly from solid to gas. This conversion occurs when dry ice (solid carbon dioxide) vaporizes at atmospheric pressure to form gaseous carbon dioxide because the…

  • sublimation line (physics)

    liquid: Phase diagram of a pure substance: …triple point is called the sublimation curve. It represents the equilibrium between solid and gas, and when the sublimation curve is crossed, the substance changes directly from solid to gas. This conversion occurs when dry ice (solid carbon dioxide) vaporizes at atmospheric pressure to form gaseous carbon dioxide because the…

  • sublimation nucleus (meteorology)

    precipitation: …atmospheric dust particles known as sublimation nuclei. In natural clouds, ice crystals form at temperatures colder than about ?15 °C (+5 °F). The exact temperature of ice crystal formation depends largely on the physical-chemical nature of the sublimation nucleus.

  • sublimation, heat of (physics)

    carbon group element: Crystal structure: … energies associated with fusion (melting), sublimation (change from solid to gas), and vaporization (change from liquid to gas) among these four elements, with increasing atomic number and atomic size, indicate a parallel weakening of the covalent bonds in this type of structure. The actual or probable arrangement of valence electrons…

  • sublime (art)

    Sublime, in literary criticism, grandeur of thought, emotion, and spirit that characterizes great literature. It is the topic of an incomplete treatise, On the Sublime, that was for long attributed to the 3rd-century Greek philosopher Cassius Longinus but now believed to have been written in the

  • Sublime Faith, Book of (work by Ibn Daud)

    Abraham ben David Halevi ibn Daud: …for his major philosophic work, Sefer ha-emuna ha-rama (“Book of Sublime Faith”), extant only in Hebrew and German translations.

  • Sublime Object of Ideology, The (work of Zi?ek)

    Slavoj ?i?ek: The Sublime Object of Ideology: The influence of Hegel is apparent in ?i?ek’s first major work, Le Plus Sublime des Hystériques: Hegel Passe (1988; “The Most Sublime of Hysterics: Hegel Passes”), a revision of his second dissertation. German idealism was subsequently an abiding interest for…

  • Sublime Porte (Ottoman government)

    Sublime Porte, the government of the Ottoman Empire. The name is a French translation of Turkish Bab?ali (“High Gate,” or “Gate of the Eminent”). which was the official name of the gate giving access to the block of buildings in Constantinople, or Istanbul, that housed the principal state d

  • Sublime Porte (government building, Istanbul, Turkey)

    vizier: …official residence known as the Bab?ali (Sublime Porte), which replaced the palace as the effective centre of Ottoman government. Beginning in the 19th century, the grand viziers presided over the council of ministers, appointed by the sultan; and after 1908 they acquired the right to appoint the cabinet ministers. The…

  • Sublime Porte Incident (Ottoman history)

    Ottoman Empire: Rise of the CUP: …23, 1913), known as the Sublime Porte Incident, to force the resignation of the grand vizier Mehmed Kamil Pa?a and establish a new cabinet under ?evket Pa?a. ?evket Pa?a, however, was not a Unionist, and it was only after his assassination (June 11, 1913) that the CUP at last succeeded…

  • sublingual gland (anatomy)

    human digestive system: Salivary glands: The sublingual glands lie directly under the mucous membrane covering the floor of the mouth beneath the tongue.

  • sublingual nicotine tablet (drug)

    smoking: Sublingual nicotine tablets: The sublingual nicotine tablet is approved for use in several European countries. Each tablet commonly contains 2 mg of nicotine and is placed under the tongue until it dissolves; the nicotine is absorbed through the oral mucosa. Common side effects include irritation…

  • sublingual tablet (drug)

    pharmaceutical industry: Tablets: Sublingual tablets generally do not have a coating and are designed so that they will dissolve when placed under the tongue.

  • sublitharenite (geology)

    sedimentary rock: Classification of sandstones: Sublithic arenites likewise contain more rock fragments than feldspar, but the amount of rock fragments is lower, ranging from 5 to 25 percent. Lithic arenites can be further subdivided according to the nature of the rock fragments, as shown in the smaller triangle of Figure…

  • sublittoral zone (marine ecology)

    marine ecosystem: Geography, oceanography, and topography: The sublittoral is the environment beyond the low-tide mark and is often used to refer to substrata of the continental shelf, which reaches depths of between 150 and 300 metres. Sediments of the continental shelf that influence marine organisms generally originate from the land, particularly in…

  • submachine gun (weapon)

    Submachine gun, lightweight automatic small-arms weapon chambered for relatively low-energy pistol cartridges and fired from the hip or shoulder. Most types utilize simple blowback actions. Using cartridges of such calibres as .45 inch or 9 mm, they usually have box-type magazines that hold from

  • submain entry (mining)

    coal mining: Ground control and roof support: Submain entries can be regarded as feeders from the mains that subdivide each major area. From the submains, panel entries take off to subdivide further a block of coal into panels for orderly coal extraction.

  • submandibular ganglion (physiology)

    human nervous system: Facial nerve (CN VII or 7): …facial nerve) and to the submandibular ganglion by way of the chorda tympani nerve (another branch of the facial nerve, which joins the lingual branch of the mandibular nerve). Postganglionic fibres from the pterygopalatine ganglion innervate the nasal and palatine glands and the lacrimal gland, while those from the submandibular…

  • submandibular gland (anatomy)

    human digestive system: Salivary glands: …serous type; those of the submandibular glands, of both serous and mucous types, with the serous cells outnumbering the mucous cells by four to one. The acini of the sublingual glands are composed primarily of mucous cells.

  • submarine (naval vessel)

    Submarine, any naval vessel that is capable of propelling itself beneath the water as well as on the water’s surface. This is a unique capability among warships, and submarines are quite different in design and appearance from surface ships. Submarines first became a major factor in naval warfare

  • submarine cable (communications)

    Undersea cable, assembly of conductors enclosed by an insulating sheath and laid on the ocean floor for the transmission of messages. Undersea cables for transmitting telegraph signals antedated the invention of the telephone; the first undersea telegraph cable was laid in 1850 between England a

  • submarine canyon (geology)

    Submarine canyon, any of a class of narrow steep-sided valleys that cut into continental slopes and continental rises of the oceans. Submarine canyons originate either within continental slopes or on a continental shelf. They are rare on continental margins that have extremely steep continental

  • submarine fan (geology)

    Submarine fan, accumulation of land-derived sediment on the deep seafloor; in configuration, a fan is like the section of a very low cone, with its apex at the lower mouth of a submarine canyon incised into a continental slope. Submarine canyons have steep courses with high walls and funnel

  • submarine fracture zone (geology)

    Submarine fracture zone, long, narrow, and mountainous submarine lineation that generally separates ocean-floor ridges that differ in depth by as much as 1.5 km (0.9 mile). The largest fracture zones, in the eastern Pacific, are several thousand kilometres long, 100 to 200 km (60 to 125 miles)

  • submarine gap (geology)

    Submarine gap, steep-sided furrow that cuts transversely across a ridge or rise; such a passageway has a steeper slope than either of the two abyssal plains it connects. Grooves known as interplain channels exist in many submarine gaps; the sediments in these channels are continuously graded. The g

  • Submarine Geology (work by Shepard)

    Francis P. Shepard: Among his principal works are Submarine Geology (1948) and, with R.F. Dill, Submarine Canyons and Other Sea Valleys (1966).

  • submarine landform (geology)

    mountain: Mid-ocean ridges and rises: Thus, such submarine landforms comprise very long, narrow volcanic centres. Although volcanoes do form as isolated seamounts along the axes of mid-ocean ridges, they constitute only a small fraction of the erupted material. Moreover, areas along the ridges and rises where volcanism is particularly abundant are considered…

  • submarine mine (weapon)

    Submarine mine, underwater weapon designed to explode when a target presents itself. See

  • submarine photometer

    undersea exploration: Collection of biological samples: …transparency and absorption include the submarine photometer, the hydrophotometer, and the Secchi disk. The submarine photometer records directly to depths of about 150 metres the infrared, visible, and ultraviolet portions of the spectrum. The hydrophotometer has a self-contained light source that allows greater latitude in observation because it can be…

  • submarine plateau (geology)

    Oceanic plateau, large submarine elevation rising sharply at least 200 m (660 feet) above the surrounding deep-sea floor and characterized principally by an extensive, relatively flat or gently tilted summit. Most oceanic plateaus were named early in the 20th century prior to the invention of

  • submarine rocket (missile)

    tactical weapons system: Surface-to-surface systems: Subroc and the Soviet SS-N-15. These missiles break the ocean surface, streak through the air at supersonic speed for about 30 miles (50 km), and then release a nuclear depth bomb that drops back into the water and sinks to the level of the target…

  • submarine sandwich (food)

    Hoagie, a submarine sandwich filled with Italian meats, cheeses, and other toppings. The name likely comes from the Philadelphia area where, during World War I, Italian immigrants who worked at the Hog Island shipyard began making sandwiches; they were originally called “hoggies” before the name

  • submarine slump (geology)

    Submarine slump, in a submarine canyon or on a continental slope, relatively rapid and sporadic downslope composed of sediment and organic debris that has built up slowly into an unstable or marginally stable mass. The greatest documented distance that an individual slump has transported sediment

  • submarine volcanic cone (geology)

    Seamount, large submarine volcanic mountain rising at least 1,000 m (3,300 feet) above the surrounding deep-sea floor; smaller submarine volcanoes are called sea knolls, and flat-topped seamounts are called guyots. Great Meteor Tablemount in the northeast Atlantic, standing more than 4,000 m

  • submarine volcano

    volcano: Submarine volcanoes: These structures occur in various forms, but many are cone-shaped seamounts. Some ancient island volcanoes were eroded flat or covered with a coral cap at sea level before they sank below the sea surface as they and the crust supporting them cooled and…

  • submarine-launched ballistic missile (military technology)

    arms control: The Cold War: Soviet and U.S.-led arms-control agreements: …of each side’s ICBMs and submarine-launched ballistic missiles (SLBMs) at current levels. The SALT II agreement (1979) set limits on each side’s store of multiple independent reentry vehicles (MIRVs), which were strategic missiles equipped with multiple nuclear warheads capable of hitting different targets on the ground. This agreement placed limits…

  • submaturity (geology)

    sedimentary rock: Texture: Submature sandstones are created by the removal of the clay matrix by current action. The sand grains are, however, still poorly sorted in these rocks. Submature sandstones are common as river-channel sands, tidal-channel sands, and shallow submarine sands swept by unidirectional currents. Mature sandstones are…

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