Kara Sea through the St. Anna and Voronin 

 Troughs. According to Milligan (1969) this 

 subsurface flow is a counterflow to the north- 

 ward flowing continental runoff. A trivial 

 amount of Atlantic water also penetrates the 

 Kara Sea through the straits between Novaya 

 Zemlya and the Siberian mainland (Zenkevitch, 

 1963; Milligan, 1969). 



Other water masses present in the Kara Sea 

 include Arctic water, which is probably formed 

 by mixing of the continental runoff and Atlan- 

 tic water, and Arctic bottom water (T<0° C, 

 S>34.0° "/„„) which enters the deepest depth of 

 the Svyataya Anna and Voronin Troughs as a 

 compensatory flow to the outflowing continen- 

 tal runoff (Milligan, 1969). 



Sea ice begins to form in the Kara Sea as 

 early as September and melting starts only in 

 June but ice cover even in midwinter is not 

 solid or continuous (Zenkevitch, 1963). The ice 

 that is formed off the Siberian coast and in the 

 rivers, and icebergs calved from the relict gla- 

 ciers on the north island of Novaya Zemlya, 

 are carried by the cyclonic surface circulation 

 into the lee of Novaya Zemlya, where they per- 

 sist even into the summer (Nordenskjold and 

 Mecking, 1928). 



Geological Setting 



The Kara Sea is situated amid rocks from 

 nearly every geologic period. Precambrain 

 shield, consisting mostly of gneisses and 

 schists, is exposed on the northern shore of 

 Taymyr Peninsula, the southwestern part of 

 Severnaya Zemlya archipelago and several 

 offshore islands (Rabkin and Ravich, 1961). 

 Slightly metamorphosed and folded Paleozoic 

 rocks, predominantly carbonates and elastics, 

 compose Novaya Zemlya, the western islands 

 of Severnaya Zemly archipelago and much of 

 the Yugorskiy Peninsula (Markov and Tkach- 

 enko. 1961). Mesozioc deposits occupy Zemlya 

 Frantsa losifa and the islands Ushakova and 

 Vize and consist mostly of friable elastics with 

 considerable organic remains including coal 

 (Dibner, 1957). The region between Yugorskiy 

 and Taymyr Peninsulas, termed the West Sibe- 

 rian Lowlands, is blanketed by a thick cover of 

 unconsolidated Quaternary deposits (Saks, 

 1948). 



The tectonics of the Kara Sea are complex 

 and not completely worked out, but several de- 



tails are clear. Novaya Zemlya and Vaigach Is- 

 land, which lies between Novaya Zemlya and 

 the Soviet mainland, are a tectonic continua- 

 tion of a mainland axis which branches off lat- 

 erally from the northern end of the Urals 

 (Nordenskjold and Mecking, 1928). Tectonic 

 trends also connect the northern border of 

 Taymyr and the Severnaya Zemlya archipelago 

 (Nalivkin, 1960) and are probably connected 

 with the Ural trend. 



Many of the islands and the floor of the 

 Kara Sea are marked by numerous abrasional 

 terraces which reflect the complex glacial and 

 postglacial history of this region. Novaya Zem- 

 lya and the Taymyr-Severnaya Zemlya region 

 were principal centers of glaciation which 

 progressed over a considerable part of the Rus- 

 sian plain (Saks, 1948; Saks and Strelkov, 

 1961). Saks (1948) concluded that tectonic 

 pulsations in the northern part of Eurasia dur- 

 ing the Quaternary rather than eustatic and 

 isostatic factors were largely responsible for 

 the oscillations in the coastal contours. None- 

 theless the beds of the Ob and Yenisey Riv- 

 ers can be traced to a depth of 100 meters in 

 the Kara Sea (Saks, 1948) and there are many 

 deltaic channels within a 35 to 70 meter depth 

 range on the continental shelf which Johnson 

 and Milligan (1967) favored as being relicts of 

 a lower sea level. The shore structure of No- 

 vaya Zemlya, on the other hand, is defined by 

 ascending vertical movements (Zenkovitch, 

 Leontiev, and Nevessky, 1960) and the rivers 

 of Western Siberia appear to be "entrenched" 

 rather than "drowned" (Lazukov, 1964). The 

 conflicting evidence of sea level fluctuations in 

 the Kara Sea has been reviewed and illustrated 

 by Lazukov (1964, see esp. fig. 1). 



Previous Work 



Klenova (1936) first outlined the general 

 sediment distribution in the southwestern 

 Kara Set. She observed that the sediments in 

 all the deeper areas were predominantly silty 

 clay or mud (over 50 percent less than 0.01 

 mm.) and terrigenous silt of glacial marine or- 

 igin and were brown in color in the upper lay- 

 ers. She also noted that the sediment texture 

 tended to reflect the cyclonic rotation of sur- 

 face water in the southwestern part of the 

 Kara Sea which permitted mud to accumulate 

 in quite shallow water. 



