8. Deep-Sea Radium and the 

 Geochionology of the 

 Ocean Floor 



Ihe very long sediment cores which the Swedish 

 Deep-Sea Expedition first managed to raise from great 

 depths have appropriately been called "records of the 

 deep." Every historian or archaeologist knows how 

 annoying it is to come across reliable but undated 

 records from the past. Hence the problem arises of how 

 these unique records of the deep can be dated, so as to 

 afford the basis of an exact geochronology for past hap- 

 penings on the ocean floor, including the climatic, 

 tectonic, and volcanic catastrophes which have left 

 indelible markings there. 



It is well known that geologists studying continental 

 rocks and sediments have labored with the same dif- 

 ficulty, that of dating the "records of the rocks." Thanks 

 to the sequence of different layers or strata in con- 

 tinental sediments, a framework of geological dating 

 was worked out. In this work study of the fossils en- 

 closed in the strata and knowledge of their evolutionary 



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