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Hacker, Bradley R.; Gnos, Edwin; Ratschbacher, Lothar; Grove, Marty; McWilliams, Michael; Sobolev, Stephen V.; Wan, Jiang; Zhenhan, Wu
Science (American Association for the Advancement of Science), 03/2000, Letnik: 287, Številka: 5462Journal Article
Anhydrous metasedimentary and mafic xenoliths entrained in 3-million-year-old shoshonitic lavas of the central Tibetan Plateau record a thermal gradient reaching about 800° to 1000°C at a depth of 30 to 50 kilometers; just before extraction, these same xenoliths were heated as much as 200°C. Although these rocks show that the central Tibetan crust is hot enough to cause even dehydration melting of mica, the absence of hydrous minerals, and the match of our calculated P-wave speeds and Poisson's ratios with seismological observations, argue against the presence of widespread crustal melting.
