GENERAL CHARACTERISTICS AND GEOLOGICAL HISTORY 



365 



marmoratus. Behning thinks that the Caspian transgression reached Lake 

 Yaskhan and there left all these relicts. 



Archangelsky's opinion, that there was no direct link between the Caspian 

 and Aral Seas, and his assumption of a complete loss of salinity by the latter 

 at the beginning of the Quaternary era, does not explain its genetic link 

 with the Caspian, which is indubitable in spite of all the poverty of its fauna. 

 Taking this into consideration V. Beklemishev (1922) relates the penetration 

 of the Caspian elements into the Aral Sea to the Maeotic period, assuming, 

 as did L. Berg (1908), the possibility of the survival of the most euryhaline 

 Caspian forms in the Aral Sea in the post-Tertiary period. С Grimm (1877) 

 gave a different explanation for the impoverishment of the Aral fauna : he 

 thought that the salinity of the Aral Sea had at one time increased greatly, 

 causing the extinction of most forms of the Caspian fauna. 



Differences in the history of the southern seas 



Thus each of our four southern seas had a separate history in the late Tertiary 

 and Quaternary Periods. The Black Sea underwent the greatest fluctuations 

 in temperature, salinity and fauna and the smallest in its water-level. The 

 Caspian Sea underwent much greater fluctuations in its level, but its salinity 

 changes were much less. 



The simplest history is that of the Aral Sea, which was only formed in the 

 middle or second half of the Quaternary Period. 



In general (I. Gerasimov and K. Markov, 1939) the history of these seas 

 can be presented in the form of Table 144. 



Table 144 



Black Sea 



Caspian Sea 



Aral Sea 



Comparison with 

 glaciation phases 



Freshened 

 Chaudin basin 



Freshened 

 Ancient Euxine 

 basin 



Brackish Uzunlar 

 basin. Saline 

 Karangat Sea 

 (connected with 

 Mediterranean) 



Slightly brackish 

 Novo-Euxine 

 basin 



Brackish Ancient 

 Black Sea (con- 

 nected with 

 Mediterranean) 



Brackish 

 Baku basin 



Freshened 

 Khazar basin 



Brackish water 

 Khavalyn basin 



Gradual lowering 

 of its level 



Aral-Sarakamysh 

 alluvium plain 



Formation of Aral 

 Sea 



Riss glaciation 



Tirrene period 



Outflow of part of 



Amu-Darya waters Wurm glaciation 



(through Uzboi) 

 Drying up of Monastyr 



Uzboi period 



