Deep Mantle Convection

详细信息      

• journal_title：AAPG Bulletin
• Contributor：W. Jason Morgan
• Publisher：American Association of Petroleum Geologists (AAPG)
• Date：1972-
• Format：text/html
• Language：en
• journal_abbrev：AAPG Bulletin
• issn：0149-1423
• volume：56
• issue：2
• firstpage：203
• section：Articles

摘要

<p id="p-1">Evidence shows that volcanic island chains and aseismic ridges are formed by plate motion over fixed-mantle "hot-spots" (Iceland, Hawaii, Galapagos, etc.) and new arguments link these hot-spots with the driving mechanism of continental drift. It is assumed that the hot-spots are surface expressions of deep mantle plumes roughly 150 km in diameter, rising 2 m/year, and extending to the lowest part of the mantle. The rising material spreads out in the asthenosphere, producing stresses on the plate bottoms. Order-of-magnitude estimates show these stresses are sufficiently large to influence plate motion significantly. the total upward flow in the plumes is estimated at 500 cu km/year, which would require the entire mantle to overturn once each 2 billion years. p>