New theory tells how Earth grows skin.Forget the purple mountains' majesty and the fruited plains. in terms of sheer surface area, they can't compare to deep-sea ridges called abyssal hills, which cover 60 to 70 percent of Earth's face. But while these hills are the most pervasive geologic feature on the planet's surface, the secret of their formation has eluded scientists for 40 years. Recent dives to the seafloor in the ALVIN submersible submersible, small, mobile undersea research vessel capable of functioning in the ocean depths. Development of a great variety of submersibles during the later 1950s and 1960s came about as a result of improved technology and in response to a demonstrated need for have now yielded an explanation of how the hills form in the Pacific Ocean, report Ken Macdonald Sir Kenneth Donald John Macdonald, QC, is Director of Public Prosecutions of England and Wales.[1] In that office he is ex officio head of the Crown Prosecution Service. He was previously a recorder (part-time judge) and defence barrister. and Russell Alexander of the University of California, Santa Barbara History The predecessor to UCSB, Santa Barbara State College, focused on teacher training, industrial arts, home economics, and foreign languages. Intense lobbying by an interest group in the City of Santa Barbara led by Thomas Storke and Pearl Chase persuaded the State , and Paul J. Fox of the University of Rhode Island History The University was first chartered as the state's agricultural school in 1888. The site of the school was originally the Oliver Watson Farm, and the original farmhouse still lies on the campus today. in Narragansett. In January, the scientists studied a section of the East Pacific Rise 1,000 kilometers southwest of Acapulco, Mexico. This midocean ridge -- part of a worldwide system -- represents the border where two of Earth's surface plates spread apart. Moving about as fast as a fingernail fin·ger·nail n. The nail on a finger. grows, the plates slowly creep away in opposite directions, opening up cracks through which molten rock can rise to the surface and then harden to form new ocean floor. Some theories about abyssal hills suggest that they develop through eruptions along the midocean ridges. Others argue that the hills form by fracturing of the crust. Evidence from the dives this year now suggests a combined theory, the scientists reported at a recent meeting of the American Geophysical Union The American Geophysical Union (or AGU) is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 140 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and (AGU AGU Aoyama Gakuin University, Tokyo, Japan AGU American Geophysical Union AGU Arabian Gulf University (Bahrain) AGU All Grown Up (TV show) AGU Aguascalientes, Aguascalientes, Mexico ) in Baltimore, Md. As the newly formed crust moves away from the center of the ridge, it stretches, causing the rock to crack. Some blocks of crust drop to form valleys, while other parts remain elevated as steep-sided hills. Later, lava erupting from the midocean ridge pours over some of the fractures, coating portions of the hills with fresh volcanic rock. This two-step process explains how abyssal hills form in the Pacific and other spots where the plates spread apart at their quickest rate, according to the scientists. Other places, where the ridges spread more slowly, may create abyssal hills differently, Macdonald says. |
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