GEOLOGICAL RECORD ON THE OCEAN FLOOR 



145 



□^ 30 — 



WINTER 



SUMMER 



SOJTH 



LATITUDE- 



Fig. 10. Meridional distribution of quartz in east Pacific sediments (lower 

 graph), velocities of high altitude winds (middle graph), and arid areas of the 

 world (top graph) (Goldberg and Rex, 1958). 



initiative of Hans Pettersson to start a quantitative study of the 

 concentration and distribution in time of the microscopic spherules 

 of nickel iron which form the perhaps most easily concentrated and 

 identified component of cosmic material in deep sea sediments. 

 Thanks to the technique developed by Kullenberg (1947) and 

 employed by him during the Swedish Deep Sea Expedition large- 

 diameter cores were available which permitted the collection of 

 statistically significant numbers of spherules from sufBciently 

 narrow depth intervals (Fig. 11). The results obtained by Petters- 

 son, Fredriksson (1958), and Laevastu and Mellis (1955) indicate 

 an increase in concentration of cosmic spherules in the Recent 

 strata, which is interesting in view of the hypothesis that meteor- 

 ites have started to reach the earth in increasing numbers in 

 historic time. This distribution has been found both in the Pacific 



