DRILLING BENEATH THE SEA — BENSON 401 



sea, using the standard piston coring apparatus lowered on a wire 

 line. Not only did the new drilling teclinique produce the first deep 

 cores, or cylindrical samples, of the deep ocean bottom, but it also 

 sampled the mysterious "second layer" of the oceanic crust, hitherto 

 studied only by seismic means. Findings proved that at least the 

 top of the layer at the site of the drillmg was basalt, a hard rock 

 formed by the solidification of lava. 



The significance of this discovery has only begiin to be debated by 

 the geophysicists and marine geologists. They are, for example, 

 puzzled by the fact that the sediment layer is not deep enough for the 

 amount of sediment estimated to have been deposited from the begin- 

 ning of the oceans. The discovery that the top of the second layer is 

 basalt could mean that the basalt, at 560 feet at the site, underlies 

 only part of the total depth of sediment and that earlier sediment 

 records lie still deeper. Conversely, it is argued that since the layer 

 is basalt, it could be the beginning of a very deep layer of hard rock. 

 This would mean that the hoped-for earlier sediments, with their 

 evidences of the formation of the oceans, somehow have been lost. 



WHAT CAN BE LEARNED? 



Wliat can be learned from the oceanic sediments ? Today, at more 

 than a dozen laboratories around the country, scientists are analyzing 

 the bits and pieces of evidence resulting from the operation. First, 

 there are the geophysical logs, the records obtained by lowering instru- 

 ments down the various holes. Then, there are the cores themselves, 

 the sections of ooze and rock bitten out of the hole by a specially 

 designed coring apparatus. From these and from subsequent tests 

 will come facts that will be worked into existing hypotheses that try 

 to explain what the ocean basins are like, how they were formed, and 

 how old they are. New facts may force a revision of some hypotheses, 

 or their rejection. In other cases, the evidence may link with other 

 facts, clarify concepts, or point new directions. In addition, there 

 is always the potential of any basic research — discovery of the 

 unexpected. 



Within the sedimentary layers will be found many new pages of 

 the history of the earth and the oceans. Mohole scientists at sea re- 

 ported finding fossil evidence of a flowering of sea life roughly 25 

 million years ago in the Guadalupe Island area. More than 100 feet of 

 nearly continuous core of the deep ocean ooze showed that sea life in 

 the area was prolific for about seven million years; by comparison the 

 area is now an oceanic desert. The upper 500 feet of sediment was 

 determined to be of late Miocene Age in the geologic time scale by 

 correlating fossils with similar ones of known age fomid m continental 

 rocks. 



