SEAMOUNT OR GUYOT. IT IS APPROXIMATELY 9 MILES WIDE AT ITS 



CREST AND RISES 9,000 FT. ABOUT THE SURROUNDING OCEAN FLOOR. 



A THIN VENEER OF SEDIMENTS OVERLIES THE IGNEOUS CORE. 





SECOND BOTTOM MULTIPLE 



BOTTOM DEPTH 12,500 FT 





■■-^■^ 



-11.5 MILES 



BOTTOM DEPTH 3500 FT 



^^ 



FIRST BOTTOM MULTIPLES; , 



.-•?% 



Figure 3. (National Science Foundation photo) 



areas of greatest challenge and need. It should be 

 our inclination to support the scientist interested 

 in the basic problems of understanding the plane- 

 tary oceans and to provide the institutional, 

 facility, and Federal support necessary to his 

 work. 



What are some of the problems that our 

 scientists find ripe for study? The nature of the 

 earth's evolution is not understood, nor why the 

 continents have their shapes and locations, nor 

 why the sea floor is rugged with ridges, seamounts, 

 and trenches. Scientists now believe that, given an 

 adequate quantity and quality of observations, an 

 explanation of these fascinating questions may be 

 near. In studying them, a store of information 

 about the sea floor and its composition can be 

 acquired for a multitude of uses which today 

 cannot be foreseen. 



Scientists are coming increasingly to believe 

 that our continents have drifted to their present 

 locations in response to the dynamic currents of 



the earth's core, that the ocean ridge system is an 

 integral part of this process. 



The theory of continental drift was set forth 

 clearly by the meteorologist Alfred Wegener in 

 1912.* It remained largely uncredited in the 

 United States until the 1960's because nobody 

 could account for any energy source capable of 

 moving masses as large as continents. Now, largely 

 due to the work of geophysicists and geochemists 

 in the ocean and on the continents, a composite 

 portrait has begun to emerge, based upon syste- 

 matic measurements of the thicknesses of ocean 

 sediments, the magnetic properties of ocean vol- 

 canic rocks, the geo-chronology of continental 

 rocks, the heat flow through the ocean floor.^ 



The case has yet to be proven and the details of 

 the mechanics yet to be understood. Scientists 



Die Enstehung der Kontinente, Wegener, Petermann's 

 Mitt. 58, 1912. 



Spreading of the Ocean Floor: New Evidence, Vine, 

 Science, Vol. 154, No. 3755, Dec. 16, 1966. 



1-21 



