The history of dying sea

Table 1

Climat chronology of halocene and stages of development of Aral sea

Divisions of

halocene

Time,

Years back

Regional pleoclmatic

scale

Types Climate

Phase of development

Aral sea

The modernity

Tetmez phase

Hot dry

Regress

-1000

Sanjar micropluvial

Semidesertic

type

Transgression

-2000

Late

Regress

-3000

New Aral basin

Tubel arid

Hot dry

-4000

-5000

Regress

-6000

Uzboy Phase

-7000

Average

-8000

-9000

Lyavlyakan pluvial

Warm

Be relative

Damp

Steppe type

(chestnut

Steppes)

Aincent-

Aral basin

Douzboy

Phase

Early

-10000

-11000

Ancient

-12000

Janak arid

Cold

Dry tundra Type

Paskevech basin

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3. A drain of the basic Central Asian rivers in late

pleistocene and halocene

Estimations of a drain of paleochannels were made on

ancient-middlehalocene of oldriver Amu Darya (Akchadarya),

Zerafshan (Echkiliksay, Daryasay, Makhandarya, Gudjayli and

Taykir) and Uzboy. Besides charges of water Janadarya - the

channel of ancient Syr-Darya functioning in Middle Ages have

been designed.

One of ways of reception of charges of water for the ancient

rivers is their calculation under hydraulic formulas in view of

characteristics of channel for chosen time. Calculation of speeds

of streams was made under Shezi formula, high-speed factors

were defined under V.N.Goncharova, N.N.Pavlovsk, A.Shtriklera's

formulas, etc./19, 25/.

At paleohydrological reconstruction of channels the most

difficult and so important is definition of a characteristic water

level, a bias of a water table and a roughness of channels. The

water level corresponding maximal channels filling to the charge

of water is in the best way expressed in a relief. More often it

either a coastal shaft, or height edge bottomland, and if the first

parameter the settlement charge is a little bit overestimated is

used and if the mark bottomland settlement charge of water is

underestimated, is used.

We had been used formulas of calculation of the charge of

water under hydraulic characteristics of channels, developed

for uniform movement at which the bias of a water table is

accepted equal to a bias of a bottom of a water-current.

The roughness of the rivers of Central Asia practically is not

investigated. Separate researches were carried out for the foothill-

mountain rivers. There are no data on a roughness paleorivers.

On G.V.Kulichihina's researches/12/for lower reaches the rivers

of the given area it is possible to recommend values of a

relative roughness within the limits of 0,020-0,025, on occassion

up to 0,040. Close values of a roughness of ancient channel of

Uzboy have been accepted also by A.S.Kes/9/.

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