638 EIGHTH PACIFIC SCIENCE CONGRESS 



matic conditions and the stability of the surface current system during 

 the Quaternary Age. On the other hand, cores of apparently homo- 

 genous Red Clay, up to 15 meters long, have been raised both from the 

 Atlantic and especially from the Pacific depths, the lowest strata of which 

 were formed during late Tertiary Time. This first evidence of Red Clay 

 of Tertiary age has forced us to a revision of our earlier views on the 

 formation of this sediment, largely based on the hypothesis of the lime- 

 dissolving power of the ice-cold Antarctic bottom current. This ex- 

 planation cannot well hold for the formation of Red Clay in the Ter- 

 tiary age. I suggest that the lime-dissolving power of magmatic volatiles 

 from the substratum affords a more general explanation. As regards 

 the rate of sedimentation there are at present three ways of obtaining 

 at least approximate values. One is through biological analyses of the 

 foram tests which, through the work of Schott in Hannover, Phleger 

 and his co-workers at Scripps Institute, Ovey and Wiseman in London 

 a.o., have yielded unmistakable proofs of past climatic changes, which 

 have been brought into relationship with paleoclimatic variations, es- 

 pecially the cold ice stages and the warm interglacial stages during Qua- 

 ternary Time. A clear-cut time relationship has so far not been estab- 

 lished, but recent work by Wiseman in London seems to open promis- 

 ing prospects to this direction. Another method, especially by Arrhe- 

 nius, is based on the assumption of a constant rate of accumulation of 

 titanium from the "lutite veil" settling on the ocean floor. Recent 

 work by Correns a. o. have, however, raised doubts on the general ap- 

 plicability of titanium-age determinations. 



A third method which we have developed and pursued in Goteborg 

 in collaboration with specialists in Vienna and in Brussels, makes use 

 of radioactive age-determinations. The surprisingly high radium con- 

 tent of abyssal sediments, especially of Red Clay and of Radiolarian 

 Ooze, first discoveied by Joly of Dublin nearly half a century ago, re- 

 mained unexplained, until a team of workers from Scandinavia and 

 Vienna took up the problem 20 years ago. The results proved that 

 the scarcity of radium in sea-water, about one sixth to one seventh of 

 the equilibrium value dissolved uranium, was due to a precipitation 

 of the intervening element ionium on the deep-sea floor, where it gives 

 rise to radium. This opens a possibility of age-determinations from the 

 known rate of decay of ionium, viz. to 1/2 in 83,000 years to 14 in 

 166,000 years, etc. A chronology of the last 300,000 to 400,000 years 

 appeared possible from radium measurements in layers at given dis- 

 tances from the sediment surface. Early attempts according to this 

 method made by Piggot 8c Urry appeared to conform with theory. Later 

 measurements by Kroll in Goteborg on a much more extensive material 

 from the "Albatross" cores, have proved the distribution to be much 



