THE ARCTIC PACK AND THE POLYNYA* 



A. Kolchak 



Characteristics of the Arctic Pack 



By the term "Arctic Pack" I understand the many-years-old ice 

 of the Arctic Ocean, mostly rafted [Russian, nabivnoi] and pre- 

 dominantly in the shape of fields, i.e. areas whose Hmits cannot 

 be seen from a ship's mast. The distinctive characteristics of the 

 Arctic Pack are : its tremendous power, greater than that of the pres- 

 sure-formed ice in the marginal seas of the Arctic Ocean ; its solidity, 

 due to the age, of many years' standing, of these rafted ice forma- 

 tions — a solidity that gradually increases to such a degree that the 

 ice masses look like a compact and homogeneous whole; and, finally, 

 the size of the areas of rafted ice, so large that they represent powerful 

 hummocky ice fields in extent. 



The Arctic Pack forms the main mass of the almost continuous ice 

 cover that spreads out over the whole oceanic part of the Arctic Basin. 

 It is in constant slow and complicated motion, as the result of which 

 local shock and pressure of the ice take place on the one hand and, 

 on the other, the formation of polynyas, channels, and cracks. 



The ice fields of the Arctic Pack may also consist of areas of many- 

 years-old ice formed by the natural thickening of the ice cover to the 

 extent limited by its conductivity of heat, a limit beyond which the 

 increase of its power must stop. Even in the Arctic seas, as has been 

 mentioned before, the development of extensive intact areas of one- 

 year-old ice is very difficult in the unfrozen part of the sea. The one- 

 year-old ice mostly turns into heaped-up ice, in the course of time 

 changing into many-years-old formations; in summer one can seldom 

 meet with any extensive unbroken areas of one-year-old ice. It is 

 still more difficult to imagine the formation of large areas of ice in 

 the Arctic Pack developing exclusively by natural freezing of the sea 

 water during the period of the predominance of freezing air tempera- 

 tures. The new ice formed in the polynyas, occasional channels, and 

 cracks throughout the moving powerful ice cover breaks up into 

 pieces under the constant shock, pressure, and squeezing of the old 

 ice, which process produces the heaped-up ice formations that later 



* Translation by Messrs. Nicholas George and N. A. Transehe of the American Geographical 

 Society's staff of Chapter ii of A. Kolchak: Led Karskago i Sibirskago Morei (The Ice of the Kara 

 and Siberian Seas), Resultats scientifiques de I'Expedition Polaire Russe en 1 900-1 903 sous la direction 

 du Baron E. Toll, Section B: Geographic physique et mathematique, Livraison i, Zapiski Imp. Akad. 

 Nauk, Ser. 8, Phys.-Math. Class, Vol. 26, No. i, St. Petersburg, 1909.— The last word in the title is 

 also spelled "polynia" in English Arctic literature. 



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