SCIENTIFIC RESULTS 



97 



American shores. If 7,500 bero:s be representative then normally 

 only 1 berg in -20 finally succeeds in drifting out of Davis Strait and 

 south of Newfoundland. The Marlon expedition's estimate of 2,200 

 bergs south of Disko Bay in the summer of 1928 in conjunction with 

 the number of bergs south of Newfoundland during the preceding 

 spi'ing indicates that the crop is not entirely destroyed during one 

 summer, but that one, two. and ])ossible three year age groups per- 

 sist in Baffin Bay and Davis Strait. 



Manner in AVhich Icebergs Calve 



The so-called calving process by wdiich end portions of a glacier 

 break away from tlieir main mass creating icebergs is a phenomenon 



Great Karajak Glacier Prior to a Major Calving 



FiGCRE .56. — The front wall of Great Karajak Glacier in Umanak Fjord, west Green- 

 land (lat. 70° 25' N., long. 50° 30' W. ) before a major calving. August 13, 1892. 

 (Jreat Karajak is one of the most productive iceberg glaciers in the north. (Photo- 

 graph by E. von Dryga!ski.) 



which has been under discussion for many years. The original con- 

 ception held that the glacier end protruding out across the threshold 

 of its molded bed lost support and through the continual accumula- 

 tion of weight finally exceeded its structural strength and broke off. 

 Such a process assumes, of course, that the bed on which the glacier 

 slides has a steeper slope tlian the ice stream, which is not invariably 

 the case. 



A later theory introduced by Rink (1889, p. 2TG), maintains that 

 icebergs are formed wdien the downward, slanted axis of the glacier 

 prolonged into the greater depths of the fjord is more and more 

 buoyed up until finally the end fractures, the iceberg rising to the 

 surface. Rink (jualified the foregoing by admitting that small 

 pieces of ice are also calved by splitting away and falling down 



