CANADIAN ARCTIC 





it pose a problem. As far as the writer is aware no fold belts have thus 

 far been proved in an ocean-type crust although parallel ridges and 

 valleys have been taken to mean folding in one or two places. Generally, 

 when fairly well defined, the parallel features are asymmetrical ridges or 

 escarpments, and considered of fault origin. The continuity of fold belts 

 across the Arctic basin, therefore, is to be considered doubtful. 



The premise of fold belts across the basin was one of the chief reasons 

 for postulating subsidence of part of a continental crust, but if the folds 

 are doubtful and the crust is seismically oceanic, then the subsidence 

 theory is improbable. A conflicting situation exists in Hakkel's publica- 

 tion (Hope, 1959a) in that he shows in a cross section oceanic crust, 

 without any indication of or provision for folding, yet on the map he 

 indicates a continuous fold belt across the deepest basin. 



The theories of permanent ocean basins and of continental drift both 

 provide for oceanic crust under the Arctic basin but in both the 

 Lomonosov Range poses a problem. It does not appear to be of volcanic 

 origin from the shape given it so far by contourers. If volcanic, the sup- 

 porters of most any theory for the origin of the Arctic basin would find a 

 compatible place for it in the framework of their concepts, but the non- 

 volcanic nature is a real enigma. Even the stretched-out nonorogenic 

 thread idea of Carey is difficult to visualize without magmatism. If the 

 future soundings indicate that the range is volcanic, and this is possible, 

 then we will have been trying to solve nonexisting problems. 



The rift theory, in view of the seismicity, seems attractive. It is in 

 harmony with oceanic crust, but as far as the writer understands it does 

 not present an explanation of the origin of the nonvolcanic ( ? ) Lomonosov 

 Range. The basins on the Alaskan side of the Range are not accounted for 

 in the rift theory. 



Roth the subsidence theory and drift theory provide for a sourceland 

 of sediments north of Alaska; the theory of permanence fails in this 

 respect. 



The orocline concept is complex but provocative and undoubtedly will 

 elicit a good deal of attention in the future. More and better data are 



Fig. 40.13. Heezen's rift theory of the Nansen basin. Map kindly supplied by Dr. Heezen. 

 The dots are earthquake epicenters. 



needed before further progress can be made on the origin of the Arctic 

 basins. The published record to the time of this writing leaves the subject 

 an enigma. 



