'i Page 10 THE BATTALION WEDNESDAY, JUNE 3, 1981 National Find it in Battalion Classified 845-2611 Scientist shows Earth age difference NO MATTER WHAT LIFE STYLE YOU CHOOSE, THERE IS ONLY ONE REAL CHOICE FOR HAIRSTYLING... United Press International WASHINGTON — A Caltech geologist thinks he knows why scientists searching the world have been unable to find rocks older than about 3.8 billion years — even though the Earth is believed to be some 4.6 billion years old. Dr. Don L. Anderson says the evidence indicates the young globe was blanketed by an ocean of molten rock and that as the liquid “froze,” the resulting crystals sank to the depths of this sea of magma — like sand settling in a pond. Thus the earliest crystallized rock on Earth probably is buried hundreds of miles beneath the surface. Anderson, professor of geophysics and director of Cal tech’s seismological laboratory, outlined his theory at a meeting last week of the American Geophysical Union in Baltimore. He said his ideas were based on a decade of research. His theory represents a sharp departure from commonly accepted ideas of Earth’s early history that hold the Earth formed with only modest amounts of melting. The key to Anderson’s hypothesis lies in Earth’s mantle, that semi-solid region between the thin crust of today and the molten core. Anderson believes the upper layers of the mantle solidified at different times from the global ocean of molten material into rock of different composition. The theory is based primarily on the fact that molten rock now coming up in crustal cracks in the middle of ocean floors is chemically quite different froiYi that coming up at oceanic islands and in the interiors of continents. Anderson said the first forming crystals in the magma ocean would have been more dense than the liquid rock — so they would sink. The elements concentrated in the early crust therefore formed the lower layers of the mantle. “As the Earth cooled, further lighter crystals began to separate out of the melt and form the upper mantle,” Anderson said. “These crystals, however, were depleted in those elements that formed the first layer, making the two layers complementary in their chemistry. “Such a scenario explains the absence of an early crust on Earth and the two contrasting magmas found at ocean ridges and ocean islands.” Anderson said the inferred composition of these two layers indicates they resulted from a 20 percent melt of the mantle. That would make the ocean of molten roch 1 , 300 miles thick if the melted material was on thesu4 one time. Me said the surface probably remained®