Dune
Dune
by Frank Herbert
THE LITERARY WORK
A novel set in the unspecified future on the fictional desert planet Arrakis; published in 1965.
SYNOPSIS
A young duke, Paul Atreides, discovers his destiny and that of his people on the planet Arrakis.
Events in History at the Time of the Novel
The first novel in a series of five, Dune introduces its readers to the Atreides family and the world of Arrakis. Frank Herbert creates in the Dune novels not merely a fictional setting but an entire world, complete with its own ecology, history, religion, and social customs. Winner of both the Hugo and Nebula awards for science fiction writing, Dune bridges the gap between the fictional future and the realistic present. Herbert’s themes, while set in the future, clearly relate to the social and historical issues of his own day.
Events in History at the Time of the Novel
Space travel
In the appendices to Dune, Herbert notes that “mankind’s movement through deep space placed a unique stamp on religion.... Immediately space gave a different flavor and sense to ideas of Creation” (Herbert, Dune, p. 501). The novel’s sacred regard for the space frontier is a reflection of the author’s own times. On October 4, 1957, the Soviet Union launched the world’s first manmade satellite, Sputnik. America looked on this aeronautic achievement as a challenge to its own struggling space program. On July 29, 1958, after months of congressional debate, President Dwight D. Eisenhower signed the National Aeronautics and Space Act of 1958, thereby establishing the National Aeronautics and Space Administration (NASA). NASA’s first project, the Vanguard satellite, added 150 researchers from the Naval Research Laboratory to its own staff of 8,000 and paved the way for the Mercury space program (1958-63). The strong scientific component formed the base for NASA’s technical leadership. By the end of 1960, the organization had built a relatively comprehensive space program.
In 1959 NASA began preparations for a manned space flight to the moon. By October of 1960, three aerospace firms had received contracts from NASA to deliver plans for a lunar-bound vehicle dubbed Apollo. Even so, Congress refused to make a definitive effort toward turning the dream into a reality. It would take another Soviet advance—this time the manned space flight of Major Yuri A. Gagarin—to spur the government into action. On May 25, 1961, President John F. Kennedy made his position clear to Congress. “I believe,” declared Kennedy “that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth” (Kennedy in Compton, p. 6). The space race had officially begun.
Throughout the decade, NASA officials worked toward achieving the goal set for them by Kennedy’s dream. His assassination in 1963 seemed to heighten the purpose of the space program, which launched the Gemini series in 1964-66. Although the United States made great strides toward the goal of reaching the moon, sending groups of two or three men into orbit between the years of 1965 and 1968, NASA also suffered severe setbacks. On January 27, 1967, three astronauts were killed on the ground in a fire that started during a test of their spacecraft. Nonetheless, the space program continued. On July 20, 1969, two American astronauts, Neil A. Armstrong and Edwin “Buzz” Aldrin Jr. became the first men to set foot on the surface of the moon. At 9:56 p.m., Central Standard Time, Armstrong declared in a transmission that was televised around the world, “That’s one small step for man, one giant leap for mankind” (Armstrong in Compton, p. 144). Indeed, once man set foot on the moon, the future possibilities for the human race seemed almost limitless. Although Herbert had published his book a few years before NASA’s landmark feat, he conveys in Dune the same sense of awe that surrounded the space program at this time.
Psychedelic drugs
The production and use of drugs plays an important role in the novel. In the story, the mining and transport of the melange spice forms the whole economic base of Arrakis. With an entire galaxy addicted to melange, Arrakis holds the key to political and economic power. The spice offers its users powers of insight that even the hero Paul cannot control.
Lysergic acid diethylamide (LSD) was first produced in 1938 by a Swiss chemist, Dr. Albert Hofmann. Hoping to use the drug in the treatment of headaches, Hofmann was disappointed when LSD proved ineffective in laboratory experiments. He left the drug in his lab untouched for five years. On April 16, 1943, Hofmann decided to attempt further experimentation. While handling the LSD, the doctor unwittingly ingested an unknown quantity. He records in his journal, “Last Friday … I was forced to stop my work in the laboratory in the middle of the afternoon and to go home, as I was seized by a peculiar restlessness associated with a sense of mild dizziness” (Hofmann in Trulson, p. 20). He notes later on in his journal that the sensation developed into a series of hallucinatory images with a kaleidoscope of colors.
LSD first came to the United States in 1949. Confined to medical and military experiments, the drug remained in research laboratories. During the 1960s, however, Dr. Timothy Leary, an assistant professor of psychology at Harvard University, brought LSD to mainstream culture. Dr. Leary had experimented with psilocybin, an LSD-like substance, and had been impressed with the drug’s ability to produce psychological effects. Convinced that the ingestion of LSD could expand consciousness, Leary became an advocate of the drug. He held sessions with his students during which everyone would take LSD and describe their experiences. With a Harvard associate, Dr. Richard Alpert, Leary founded the International Federation for Internal Freedom (1FIF). He soon gained national acclaim, with stories on the IFIF appearing in the New York Times. When Harvard fired both Leary and Alpert, it only accelerated their popularity, and LSD quickly became a recreational drug.
With no known medical value, LSD was primarily used in social settings. Looking to Dr. Leary as an example, others formed their own LSD groups. They developed a drug-related lingo, referring to LSD as “acid,” to LSD users as “acid heads,” and, more specifically, to experienced users as “gurus.” The hallucinatory experience was called a “trip,” and someone on a “bad trip” was said to be “freaking out.” This jargon developed during the social gatherings at which users consumed LSD. Within time, a small counterculture comprised mostly of young people rebelling against mainstream values and behaviors would embrace the drug. Rock lyrics referred to the virtues of LSD. In 1967 the Beatles released their Sergeant Pepper’s Lonely Hearts Club Band, an album thought to be influenced by the drug or to contain veiled references to drug experiences. Hippies congregated at rock concerts, love-ins, be-ins, and rallies where much of the crowd used the drug. Like the melange spice of Dune’s Arrakis, LSD seemed to permeate almost every corner of American culture. While it certainly was not the only catalyst for the social revolution of the 1960s, the drug did play a major role in it. In 1967 President Lyndon Johnson passed a bill making the drug illegal. While some contended that psychedelic drugs were a definite health hazard, others felt that the laws against LSD were prompted by a fear that LSD users would engage in anti-establishment activities.
The dangers of hero worship
The concept for Dune began with a longing “to do a novel about the messianic convulsions which periodically inflict themselves on human societies. I had this idea that superheros were disastrous for humans” (Herbert in O’Reilly, p. 38). Within the novel, there is a cloud hanging over Paul Atreides’s rise to power. Dune concerns itself with the dangers of hero worship, of which Paul is mindful. Although he earns the reputation of a religious leader, Paul feels uncomfortable in this position. Indeed, he envisions death and destruction when he looks into a possible future as a political and religious messiah. He struggles internally over the issue, not wanting to abuse his power.
The 1960s saw the appearance of cults and cult leaders in America. During this decade, youth dominated American society; in 1964 the median age was twenty-nine. The large number of young people coming of age in the 1960s possessed a good deal of idealism and optimism. They tended to place less emphasis on traditional Judeo-Christian religion because many of them felt that these religions were based on fear and pessimism. A group of intellectuals known as the “Death of God theologians” asserted that the Judeo-Christian God had no place in a modern world. Led by such scholars as William Hamilton, these men and women held that the decade of the 1950s, with its Cold War fears of nuclear devastation, had been a time of angst, and that with the arrival of the sixties “a new spirit [was] in the land” (Ellwood, p. 139). The traditional concepts of God were pushed aside during this time, and others lined up to replace them.
Several bodies of iconoclastic worship sprung up across the country. In 1966 Anton LaVey formed the Church of Satan in his San Francisco home, appropriately colored black. Through his Hollywood affiliations and his role as the devil in the movie Rosemary’s Baby (1968), LaVey found quite an audience. He and his followers saw the conventional God as a tyrant of repression, while Satan represented freedom and self-expression. LaVey, however, did not stand alone in his quest for an alternative figure of worship. In 1965 A. C. Swami Bhaktivedanta Prabhupada emigrated from India to New York. Embarking on a spiritual mission to spread the love of the Hindu god, Krishna, Swami Bhaktivedanta offered his followers a communitarian lifestyle and a spiritual high. The poet Allen Ginsberg described his Krishna experience stating, “I started chanting to myself, like the Swami said … and suddenly everything started looking so beautiful … like I’d taken a dozen doses of LSD.... [But] there’s no coming down from this” (Ginsberg in Ellwood, p. 143). In this time of innovative spirituality, other movements such as Nichiren Shoshu, Scientology, and the Unification Church found followers as well. In fact, a study conducted at Brooklyn College concluded that between the years of 1965 and 1980, 1300 new cults appeared in the United States, boasting a membership of between 2 and 3 million individuals. Although these cults initially seemed like inviting alternatives to a distressed society, some proved dangerous. The 1970s saw a rise in so-called religious groups that exploited followers in a manner similar to what happens in Dune. Using techniques of peer pressure, sleep deprivation, indoctrination, and diet control, cults attracted and maintained followers using less-than-holy motives. They isolated their members from the outside world and confiscated all money and personal possessions. In this manner, cults themselves became quite rich and powerful. The People’s Temple, led by Jim Jones, for instance, held over $10 million in several bank accounts at its peak of popularity. When the government and other agencies began investigating this group, death and destruction ensued. In 1978 a United States congressman traveled to Guyana to look into claims that the People’s Temple, ensconced in a compound in the jungle, was holding members against their will. After killing the congressman and his party, Jim Jones led 911 women, men, and children to their own deaths by drinking cyanide-laced Kool-Aid. Obviously this example represents an extremity of cult violence, but Herbert’s warnings of the dangers of hero worship had merit. The future that he foretells in Dune was perhaps closer at hand than even he imagined.
The Novel in Focus
The plot
On the lush, tropical planet of Cal-adan, Duke Leto Atreides prepares his family for their impending geographical and political move. As head of one of the Great Houses of the Land-sraad galaxy, Leto will soon assume leadership of the desert planet Arrakis. Although barren in landscape, the dunes of Arrakis house the galaxy’s supply of the valuable spice melange. Because of this resource, the House that obtains leadership of Arrakis also holds the key to a bounty of wealth and power. Leto enters this position knowing, however, that danger lies ahead. The House Harkonnen, the previous masters of Arrakis, had reigned there for over eighty years. Its leader, Baron Vladimir Harkonnen, is not prepared to abandon Arrakis without a fight. The Padishah Emperor, who rules above both these leaders as head of the galaxy, wants the baron replaced.
The move to Arrakis represents a political plan that developed over many generations. Nothing concerning the Atreides clan occurs by happenstance. Duke Leto’s son, Paul, for instance, has received training throughout all fifteen years of his life from various masters of arts. From Thu-fir Hawat, Leto’s Master of Assassins, Paul learns how to survive an assassin’s attack. From Gurney Halleck, Paul receives schooling in man-to-man combat. From Dr. Wellington Yueh, Paul learns about poisons and eventually treachery. Perhaps the most effective teacher, however, is Paul’s mother, Jessica. A Bene Gesserit “witch,” Jessica has had her own schooling in various forms of sorcery. Although only women typically receive such training, Jessica nonetheless passes on her knowledge to her son. Such a multifac-eted upbringing has molded Paul Atreides into a noble heir, and a formidable foe.
After settling into the new quarters on Arrakis, Duke Leto begins to show Paul the world of his inheritance. Although it promises great wealth, the planet requires a strong, determined hand to gain control of it and guide it. From its climate to its predators, Arrakis proves difficult to conquer. When Paul and his father travel out to the desert mine stations where the sand gets stripped of the melange spice, they catch their first glimpse of the enormous sand worms that patrol the desert. Often reaching hundreds of meters in length, the worms render the deep desert uninhabitable for most humans. They move toward and attack vibrations in the earth, and their size allows them to swallow entire mining stations whole. Although the miners have their own defense mechanisms for dealing with the worms, a lone man would probably perish. In addition to the worms, the desert also promises harsh storms and a deadly lack of water. The few cities on Arrakis stand behind Shield Walls that protect them from these dangers. Only the Arrakeen natives, the Fremen, seem fit to survive in the outer reaches of the wasteland. Through the use of still-suits, garments made to recycle the body’s own water and waste, the Fremen thrive in the dry climate. They live in sietches, or small communities spread far throughout the deep desert.
The arrival of the Atreides clan on Arrakis marks the beginning of a new way of life for some and the end of life for many. Unbeknownst to Duke Leto, Dr. Yueh has turned against him and joined forces with Baron Vladimir. During a carefully planned ambush, Dr. Yueh captures the Duke and turns him over to the Harkonnens. Both the Duke and Dr. Yueh perish in this battle. Although the others escape, only Paul and his mother remain together. The other surviving members of the House of Atreides scatter to avoid the Harkonnen onslaught. Baron Vladimir and his men believe erroneously that the entire House of Atreides has been exterminated. The Duke’s Master of Assassins, Hawat, falls into the hands of Baron Vladimir, who keeps him alive as an assistant. Meanwhile, another one of Paul’s teachers, Halleck, joins a band of spice smugglers and remains on Arrakis to plot revenge against the Baron. Eventually Paul and Jessica meet up with a group of Fremen. Although the natives do not initially welcome the two Atreides, they ultimately decide to aid the foreigners. An ancient Fremen legend tells of Lisan Al-Gaib, a prophet from another world who will bring bountiful water to the land of Arrakis. Because of Paul’s unique abilities, including a kind of extrasensory perception, the Fremen come to believe that he is Lisan Al-Gaib. Even Jessica senses that her son may fulfill a destiny more significant than just assuming the duchy of Arrakis.
Over the next two years, Paul and the Fremen leaders train their people as skilled combatants. Gurney Halleck serendipitously meets up with Paul and joins with the Fremen army. Together Paul, Halleck, and the Fremen plan their attack against the House Harkonnen. Disabling the Shield Wall that surrounds the capital city, the Fremen army invades the Baron’s headquarters. Baron Vladimir meets his demise in the ensuing battle, and Paul gains control of the planet. His plot, however, involves more than the reclaiming of Arrakis. Through the Fremen he learns that the precious melange spice, on which the whole galaxy depends, is a byproduct of the sand worms. Killing the worms would mean ending the spice production. Paul uses this threat to gain control of the galaxy’s throne. The close of the novel promises a marriage between Paul and the Padishah Emperor’s daughter, sealing Paul’s place as the future Emperor. With this deal, Paul avenges his father’s death and brings peace to the land of Arrakis.
An ecological message
Herbert takes great pains to describe the ecological makeup of Arrakis. The planet’s desert environment provides both a backdrop and an impetus for much of the action within the novel. Although the desert-dwelling Fremen come to regard Paul Atreides as a godlike figure, their first leader occupied a role other than that of a statesman. This first leader, the ecologist Liet-Kynes, delivers an environmental sermon to his followers. He states, “There’s an internally recognized beauty of motion and balance on any man-healthy planet.... Its aim is simple: to maintain and produce coordinated patterns of greater and greater diversity” (Dune, p. 493). This reflects a reverence for the environment that appears throughout Herbert’s works and recalls the author’s own heritage as well.
Born in Tacoma, Washington, Herbert’s family resided in a rural area. This country upbringing, according to the author, produced a certain self-reliance that a city lifestyle would not provide. During his retirement, in fact, the author maintained a small farm in Port Townsend, Washington. Regarding the farm as an “ecological demonstration project” (Herbert in O’Reilly, p. 15), Herbert and his wife envisioned a five-year-plan that would show how a high quality of life could be sustained with minimal stress to the environment. The couple grew their own vegetables and raised their own poultry; Herbert also built an electricity-generating windmill that earned him a patent from the federal government in 1978. The manure that the Herberts recovered from their chickens provided enough methane gas to generate their own power supply. Any additional energy needed came from solar panels. The author even maintained a vineyard that produced grapes for wine. Although this ecologically sound plan won Herbert an almost cultlike following of environmentalists during this time, he shied away from a public lifestyle and instead tried to communicate his ideas through the pages of his novels.
Perhaps the most climactic moment of Paul Atreides’s career occurs during his test of ascension to Fremen manhood. In order to prove himself worthy of his adoptive culture, Paul must harness and ride one of the sand worms. Unlike the other denizens of Arrakis, the Fremen do not fear or seek to destroy the sand worms. They understand the creatures’ value in the environmental cycle and learn to coexist with these virtual monsters. As the only society on Arrakis that survives in the deep desert with little water and in constant contact with the worms, the Fremen represent Herbert’s notion of a self-sufficient people. They sustain their lifestyle with minimum stress to the environment, and eventually earn the reward of ascending to political power on Arrakis.
Sources
Although the planet of Arrakis is an entirely fictional world, Herbert does draw some of its inhabitants from his own life. For instance, the author’s paternal grandmother, while unschooled and illiterate, possessed an uncanny memory for dates, names, and places. Herbert built on this family trait, developing some superhuman characters for Dune called the Men-tats, whose brain power is phenomenal. Derived from the Latin word mentis, meaning “of the mind,” the Mentats embody logic and reason. As a lead counselor to Duke Leto, Thufir Hawat earned the reputation as the greatest Mentat of the Imperium. Herbert’s grandmother offered inspiration in other areas as well. When excited, she would break into a dialect that resembled Elizabethan English. From this childhood exposure to other languages, Herbert developed his own interest in dialects. He uses the notion of other tongues throughout the Dune series. Paul, for example, has to learn various languages. Other family members also proved influential. For instance, Herbert’s ten maternal aunts provided the idea for the Bene Gesserit witches, who speak their own special language.
The author did not rely solely on his immediate family for inspiration. For models of the Fremen characters, Herbert turned to biographies of American Southwest Indians and North African nomads. Like the American Indians, the Fremen exist as foreigners in their own land. Their knowledge of the environment and their mastery of weaponry, however, makes them formidable foes. Also like the Southwest Indians, the Fremen practice a religion that incorporates a psychedelic-based sacrament. Even more than the American Indians, however, the Fremen resemble seventh-century Bedouin nomads. Their language, clothing, and customs seem Arabic in nature while their environment closely resembles the African desert. Herbert felt that a figure such as his prophet, Lisan Al-Gaib, would be more readily accepted in a desert environment historically related to such faiths as Islam, Judaism, and Christianity. Finally, though Herbert did study the two aforementioned cultures as preparation for the novel, with the Fremen he certainly creates his own society. The characters of Arrakis, from wherever they originate, come to full fruition in the author’s own mind.
Reception of the novel
Published in 1965, Dune found immediate critical and popular success. As mentioned, the novel earned both the 1966 Hugo Award and the 1965 Nebula Award for its author. In fact, science-fiction aficionados often point to the Dune chronicles as evidence that the science fiction genre should receive more credibility as serious writing. Herbert cultivated the unique ability to fuse his writing with current social issues. One critic commented that “[One] of the most spectacularly successful science-fiction novels of recent years, Frank Herbert’s Dune, [is a good example] of how public concerns and infatuations catch up with the science fiction imagination” (Sheppard in Bryfon-ski, p. 270). A second reviewer remarked: “It is the unstultified vigor of Herbert’s imagination which is responsible for the complexity, the depth, and the symbolic virtuosity of his novel” (Owner in Bryfonski, p. 273). Aside from its entertainment value, the novel succeeded as a vehicle for thought-provoking social commentary.
For More Information
Bryfonski, Dedria, ed. Contemporary Literary Criticism. Vol. 12. Detroit: Gale Research, 1980.
Compton, William David. Where No Man Has Gone Before. Washington D.C.: National Aeronautics and Space Administration, Science and Technical Information Division, 1989.
Ellwood, Robert S. Spiritual Awakenings. New Brunswick, N.J.: Rutgers University Press, 1994.
Herbert, Frank. Dune. New York: Ace Books, 1965.
McNelly, Willis Everett. The Dune Encyclopedia. New York: Berkley, 1984.
O’Reilly, Timothy. Frank Herbert. New York: Fredrick Ungar, 1981.
Trulson, Michael E. LSD: Visions or Nightmares. New York: Chelsea House, 1985.
Dune
Dune
A dune is a windblown pile of sand. Over time, dunes become well-sorted deposits of materials by wind or water that take on a characteristic shape and
that retain that general shape as material is further transported by wind or water.
Desert dunes classifications are based upon shape include barchan dunes, relic dunes, transverse dunes, lineal dunes, and parabolic dunes. Dunes formed by wind are common in desert area and dunes formed by water are common in coastal areas. Dunes can also form on the bottom of flowing water (e.g., stream and river beds).
When water is the depositing and shaping agent, dunes are a bedform that are created by saltation and deposition of particles unable to be carried in suspension. Similar in shape to ripples—but much larger in size—dunes erode on the upstream side and extend via deposition the downstream or downslope side. Regardless of whether deposited by wind or water, dunes themselves move or migrate much more slowly than any individual deposition particle.
The sediments that accumulate on the windward slope are called topset deposits. When they reach the crest, they form an unstable and temporary surface called the brink. When enough sediments are captured on the brink they eventually tumble over the edge onto the slipface. This motion provides the advancement of the dune as it migrates in the direction of the wind. A temporary halt in dune movement can make a thin layer of sediments that become slightly bonded to one another. This layer becomes visible in side view and is even more recognizable in ancient deposits.
The sand forming dunes is usually composed of the mineral quartz eroded from rocks, deposited along streams or oceans or lakes, picked up by the wind, and redeposited as dunes. Sand collects and dunes begin to form in places where the wind speed drops suddenly, behind an obstacle such as a rock or bush, for example, and can no longer transport its load of sand.
Dunes move as wind bounces sand up the dune’s gently-sloping windward side (facing the wind) to the peak of the slope where the wind’s speed drops and sends sand cascading down the steeper lee side (down-wind). As this process continues, the dune migrates in the direction the wind blows. The steeper lee side of the dune, called the slip face, maintains a 34° angle (called the angle of repose), much greater than the flatter (10°-12°) windward side. The sand may temporarily build up to an angle greater than 34°, but eventually it avalanches back to the angle of repose. Given enough sand and time, dunes override dunes to thicknesses of thousands of feet, as in the Sahara Desert, or as in the fossilized dunes preserved in the sandstone of Zion and Arches National Parks in Utah. In the famous Navajo Sandstone in Zion National Park, crossbeds (sloping bedding planes in the rock) represent the preserved slip faces of 180-million-year-old former dunes.
Three basic dune shapes—crescent, linear, and star—range in size up to 330 feet (100 m) high and up to 1, 000 feet (300 m) long and wide. Barchan and parabolic dunes are crescent-shaped like the letter C. Barchans form where the sand supply is minimal. The two ends of the barchan’s crescent point down-wind toward the direction the dune moves. In contrast, the pointed ends of a parabolic dune stab into the wind, a mirror image of a barchan. Bushes or some other obstruction anchor the tips of a parabolic dune.
Transverse and longitudinal dunes form as long, straight, or snakelike ridges. Transverse ridges run perpendicular to a constant wind direction, form with an abundance of sand available, and are asymmetric in cross section (the windward side gently-sloped, the slip face steep). The ridges of longitudinal dunes, however, run parallel to a slightly varying wind direction and are symmetrical in cross section—they have slip faces on either side of the ridge. Longitudinal dunes are also known as linear or seif (Arabic for sword) dunes.
Dune fields are large features of eolian or arid environments. They are associated with hot climate deserts such as the Sahara. Dune fields are not, however, exclusively restricted to these types of environments. Many dune fields are found in temperate climates where the processes of aridity in an arid climate combine to form dunes, but at a much slower rate than hot, arid climates.
Dune fields themselves are complex environments. Within the field, there are many microenvironments that lie between the dunes and at the bottom of dune valleys. Moisture may even accumulate and form small ponds. Scientists continue to study dunes and dune fields. They are one of the least understood structures in geology because of the difficulty in studying them. However, dune fields occur over about 30% of Earth’s surface and certainly command more attention.
The formation and movements of dune fields are also of great interest to extraterrestrial or planetary geologists. Analysis of satellite images of Mars, for example, allow calculation of the strength and direction of the Martian winds and provide insight into Martian atmospheric dynamics. Dunes fields are a significant Martian landform and many have been observed to have high rates of migration.
See also Desertification; Erosion; Sediment and sedimentation; Sedimentary environment; Sedimentary rock.
Resources
BOOKS
Goudie, Andrew S. et. al. Aeolian Environments, Sediments, and Landforms Hoboken, NJ: John Wiley & Sons, 2000.
Tack, Francis and Paul Robin. Dunes Paris: Vilo International, 2002.
OTHER
U.S. Geological Survey. “Types of Dunes” <http://pubs. usgs.gov/gip/deserts/dunes> (accessed November 20, 2006).
Brook Hall
K. Lee Lerner
Dune
Dune
A dune is a wind-blown pile of sand . Over time , dunes become well-sorted deposits of materials by wind or water that take on a characteristic shape and that retain that general shape as material is further transported by wind or water.
Desert dunes classifications are based upon shape include barchan dunes, relic dunes, transverse dunes, lineal dunes, and parabolic dunes. Dunes formed by wind are common in desert area and dunes formed by water are common in coastal areas. Dunes can also form on the bottom of flowing water (e.g., stream and river beds).
When water is the depositing and shaping agent, dunes are a bedform that are created by saltation and deposition of particles unable to be carried in suspension. Similar in shape to ripples—but much larger in size—dunes erode on the upstream side and extend via deposition the downstream or downslope side. Regardless of whether deposited by wind or water, dunes themselves move or migrate much more slowly than any individual deposition particle.
The sediments that accumulate on the windward slope are called topset deposits. When they reach the crest, they form an unstable and temporary surface called the brink. When enough sediments are captured on the brink they eventually tumble over the edge onto the slip-face. This motion provides the advancement of the dune as it migrates in the direction of the wind. A temporary halt in dune movement can make a thin layer of sediments that become slightly bonded to one another. This layer becomes visible in side view and is even more recognizable in ancient deposits.
The sand forming dunes is usually composed of the mineral quartz eroded from rocks , deposited along streams or oceans or lakes, picked up by the wind, and redeposited as dunes. Sand collects and dunes begin to form in places where the wind speed drops suddenly, behind an obstacle such as a rock or bush, for example, and can no longer transport its load of sand.
Dunes move as wind bounces sand up the dune's gently-sloping windward side (facing the wind) to the peak of the slope where the wind's speed drops and sends sand cascading down the steeper lee side (downwind). As this process continues, the dune migrates in the direction the wind blows. The steeper lee side of the dune, called the slip face, maintains a 34° angle (called the angle of repose), much greater than the flatter (10°-12°) windward side. The sand may temporarily build up to an angle greater than 34°, but eventually it avalanches back to the angle of repose. Given enough sand and time, dunes override dunes to thicknesses of thousands of feet, as in the Sahara Desert, or as in the fossilized dunes preserved in the sandstone of Zion and Arches National Parks in Utah. In the famous Navajo Sandstone in Zion National Park, crossbeds (sloping bedding planes in the rock) represent the preserved slip faces of 180 million year old former dunes.
Three basic dune shapes—crescent, linear, and star—range in size up to 330 ft (100 m) high and up to 1,000 ft (300 m) long and wide. Barchan and parabolic dunes are crescent-shaped like the letter C. Barchans form where the sand supply is minimal. The two ends of the barchan's crescent point downwind toward the direction the dune moves. In contrast, the pointed ends of a parabolic dune stab into the wind, a mirror image of a barchan. Bushes or some other obstruction anchor the tips of a parabolic dune.
Transverse and longitudinal dunes form as long, straight, or snake-like ridges. Transverse ridges run perpendicular to a constant wind direction, form with an abundance of sand available, and are asymmetric in cross section (the windward side gently-sloped, the slip face steep). The ridges of longitudinal dunes, however, run parallel to a slightly varying wind direction and are symmetrical in cross section—they have slip faces on either side of the ridge. Longitudinal dunes are also known as linear or seif (Arabic for sword) dunes.
Dune fields are large features of eolian or arid environments. They are associated with hot climate deserts such as the Sahara. Dune fields are not, however, exclusively restricted to these types of environments. Many dune fields are found in temperate climates where the processes of aridity in an arid climate combine to form dunes, but at a much slower rate than hot, arid climates.
Dune fields themselves are complex environments. Within the field, there are many microenvironments that lie between the dunes and at the bottom of dune valleys. Moisture may even accumulate and form small ponds. Scientists continue to study dunes and dune fields. They are one of the least understood structures in geology because of the difficulty in studying them. However, dune fields occur over about 30% of Earth's surface and certainly command more attention.
The formation and movements of dune fields are also of great interest to extraterrestrial or planetary geologists. Analysis of satellite images of Mars , for example, allow calculation of the strength and direction of the Martian winds and provide insight into Martian atmospheric dynamics. Dunes fields are a significant Martian landform and many have been observed to have high rates of migration .
See also Desertification; Erosion; Sediment and sedimentation; Sedimentary environment; Sedimentary rock.
Resources
books
Goudie, Andrew S., et. al. Aeolian Environments, Sediments, and Landforms. Hoboken, NJ: John Wiley & Sons, 2000.
Tack, Francis, and Paul Robin. Dunes. Paris: Vilo International, 2002.
other
United States Geological Survey. "Types of Dunes." (cited February 24, 2003) <http://pubs.usgs.gov/gip/deserts/dunes/>.
Brook Hall
K. Lee Lerner
Dune
Dune
The 1965 epic novel by Frank Herbert (1920–1986) about a desert planet has become one of the most successful science-fiction series ever. The original novel, Dune, led to five sequels and two films as well as a variety of nonfiction books, games, and Internet (see entry under 1990s—The Way We Lived in volume 5) sites. In addition, after the death of Herbert, his son, Brian Herbert (1947–), began publishing a series of "prequels" to the original story. The prequels focused on events set prior to the story told in Dune.
Set in a distant galaxy, Dune is the story of Paul Atriedes, son of Duke Leto, whose family is ordered by the Emperor to take charge of Arrakis, a desert planet that is the sole source for an addictive spice that produces mystical powers in some people. Before long, Duke Leto is betrayed and killed by agents of his mortal enemy, Baron Vladimir Harkonnen. Most of the Duke's subjects are either killed or enslaved, but a few escape, along with Paul and his mother, Jessica. The pair are taken in by the Fremen, the warlike native people of Arrakis. In time, Paul leads the Fremen in a war to reclaim their planet from the Harkonnens. Dune explores important questions concerning ecology, religious fanaticism, and national self-determination.
The saga, which explores the interconnected fates of the planet Arrakis, the Fremen, and the Atriedes family, was continued by Herbert in Dune Messiah (1970), Children of Dune (1976), God Emperor of Dune (1981), Heretics of Dune (1984), and Chapterhouse Dune (1985).
The original novel was filmed in 1984 by David Lynch (1946–), who would later create the TV series Twin Peaks. The film starred Kyle MacLachlan (1959–) as Paul Atriedes. It did poorly at the box office but has gained a cult following. The book was filmed again by director John Harrison as Frank Herbert's Dune. It was shown as a three-part miniseries on the cable channel Sci-Fi in January 2001 and was well received by Dune fans. The fans felt the miniseries was much closer to the original novels.
Brian Herbert's prequels began in 2000 with House Atreides, and was followed by House Harkonnen in 2001; The Butlerian Jihad was scheduled to follow.
—Justin Gustainis
For More Information
Herbert, Brian, ed. The Notebooks of Frank Herbert's Dune. New York: Perigee Books, 1988.
Herbert, Frank. Dune. New York: Chilton, 1965; Ace Books, 1990.
McNelly, Willis E., compiler. The Dune Encyclopedia. New York: Berkley Books, 1984.
Vinge, Joan D. The Dune Storybook. New York: Putnam Publishing, 1984.
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dune / d(y)oōn/ • n. a mound or ridge of sand or other loose sediment formed by the wind, esp. on the sea coast or in a desert: a sand dune.