ARTICLE IN PRESS Quaternary International 173–174 (2007) 125–136 Uzboy and the Aral regressions: A hydrological approach Rene´ Le´tollea, , Philip Micklinb, Nikolay Aladinc, Igor Plotnikovc a Universite´ Pierre et Marie Curie, Paris, France Western Michigan University, Kalamazoo, USA c Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia b Available online 21 March 2007 Abstract The Uzboy is an enigmatic dry river channel in Western Central Asia. This 750 km long channel regained life on several occasions after the end of the Wu¨rm glaciation (about 11,000 years BC), due to climatic episodes more humid than today and/or human deviations of the main course of the Amu Darya towards the west. Much of the Amu annual flow was diverted elsewhere. The discharge of Amu Darya in the Zaunguz desert accounts for the tens of km3 of water the Uzboy was unable to convey away. It appears reasonable to conclude that the Amu Darya could not carry more than 20–30 km3 per year to the Sary Kamysh lake, due to the channel cross-section at Daryalyk and Daudan Darya, at a time when the total water output of Amu Darya to Aral was about 60–70 km3 per year. r 2007 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction The Uzboy is an enigmatic dry river channel in Western Central Asia (Fig. 1). Correctly mapped by Konshin in 1884, the geological setting of the Uzboy has been thoroughly studied by Kes from 1937 until recently (chapters in Tolstov and Kes, 1960; Tolstov, 1962; Andrianov, 1969; Kes and Klyukanova, 1999). For a brief review of the first discoveries, see Wood (1876), Morgan (1878), and Yusupov (1996, 2001). For a recent monograph, one may refer to Le´tolle (2000). Although some authors assert, without any conclusive arguments, that the Uzboy never was a real river, Kes (1991, 1997) clearly demonstrated that it was an important river and a western branch of the Amu Darya. This paper establishes some hydrological parameters of the most recent characteristics of the Uzboy flow, in the Middle Ages, and especially in the XVIth century A.D., when the Aral suffered a regression of at least the same importance as the present one. This epoch is the best documented and geomorphological characteristics of the channel remain essentially unchanged since this time. The Uzboy was Corresponding author. Tel.: +33 142372856; fax: +33 142372856. E-mail address:
[email protected] (R. Le´tolle). unable to carry all the Amu Darya’s flow and other dissipative processes must have been operative. This 750 km long channel (Fig. 1) regained life on several occasions after the end of the Wu¨rm glaciation (about 11,000 years BC), due to climatic episodes more humid than today and/or human deviations of the main course of the Amu Darya towards the west. Today this channel is dry except for several elongated small p