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ISSN 2224-5278
Series of Geology and Technical Sciences 1. 2022
Figure 1. Groundwater sampling points. 1 - Kuiylys, 2 - Kuiylys 2, 3 - Zhyngyldy, 4 - Ulanak, 5 - Saubet,
6 – Sad - Dubskogo, 7 - Moinak, 8 - Prohlada, 9 - Asar, 10 - Baskudyk, 11 - Sauskan, 12 - Tuesu, 13 -
Shagala, 14 - Beineu, 15 - Sam
The sampled areas are located within the Mangystau-Ustyurt hydrogeological basin,
which occupies
the southwestern part of the vast Turan plate and is located to the south of the Caspian hydrogeological
basin. Four structural-geomorphological types of relief are quite clearly distinguished within it: the North
Mangystau Lowland (Bozashi Peninsula), the Mountain (Central) Mangystau, the South Mangystau Plateau
and the Ustyurt Plateau.
The North Mangystau Lowland (Bozashi) is a marine accumulative plain. Its plain surface occupies
absolute marks from minus marks near the sea and within the saline lands of Dead Koltuk and Kaidak, and
in the south-west and the northern slope of North Aktau, and the downdraft plain in the central part to the
absolute mark of zero to 80-100 m. The surface of the latter is complicated by salt depressions (Ulkensor,
Kyzylsor, Myasteksor, Kyzansor, etc.) and small massifs of aeolian sands (Kyzylkum, Shol-Shagyl, Uakkum,
Zhinishke, etc.). To the south and south-west of the Mangystau Mountains stretches the South Aktau Upland,
the southern slope of which gradually turns into the South Mangystau Plateau. The latter in the northwest
direction includes the Tupkaragan Plateau, which with the South Mangystau Plateau itself forms a single
uniform type of relief. Their flat surface is composed of Neogene and Upper Cretaceous limestones. The North
Aktau elevation forms a similar relief type in the north of the Mangystau Mountains. Its surface slopes more
steeply towards the Bozashi depression, in the North Mangystau, from 250-280 m to 50-30 m, in the south-
west the slope of the North Aktau Upland passes into the Prikaratau Valley and the Caspian Sea depression
with a sharply steep precipice. The northern and central parts of the South Mangystau Plateau are complicated
by deep drainless depressions (Karagiya, Kaundy, Basgurly and Zhazgurly, Uzen). The large Karinzharyk
depression separates this plateau in the east from the Ustyurt plateau. In the northeast of the South Mangystau
plateau are the Sauskan, Bostankum and Tuyesu sand massifs. To the east and northeast of the Mangystau
plateaus and the Bozashi lowlands, separated from them by a steep scarp - chink, 100-200 m high, extends the
Ustyurt plateau. Its flat and armored surface with Neogene limestone-shells is complicated by rare enclosed
hollows, sinkholes and sand massifs in the north (Sam and Mataykum) and elevated sublatitudinal rampart -
in the central part.
The climate of the territory is deserted, the average annual atmospheric temperature varies from north to
south: January from -10 to -3
o
C and July from 27 to 38
o
C, and the average annual precipitation from 100-120
mm in the south to 200 mm in the north. The aridity of the climate determines the complete absence of surface
water sources in the region.
There are three major structural-tectonic zones in the basin: the Central Mangystau-Ustyurt dislocation
system, the Bozashy-Severustyurt and South Mangystau-Ustyurt deflection zones. Ancient formations
involved in the geological structure of the region are Permo-Triassic folded rocks and the Jurassic blanket
deposits, which come to the day surface in the central (mountainous) part of the region. They are exposed
within the Prikaratau valley framing Karatau mountain massifs and Alb Cenomanian deposits, which further
in the territory of the South Mangystau and Ustyurt plateau, as well as in the North Mangystau depression
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N E W S of the Academy of Sciences of the Republic of Kazakhstan
sink to a depth of 50-100 m, and in the Prekaratau valley to 700-800 m and more. They are overlapped by
Upper Cretaceous, Paleogene and Neogene sediments, the upper part (Upper Miocene-Pliocene) of which
composes the daily surface of the Southern Mangystau and Ustyurt plateaus. In some areas, in particular, in
the North Mangystau depression there are sand massifs.
Aquifers, aquifer systems and other groundwater data are mapped in Kazakhstan on the maps taking
into account the requirements for displaying geographical objects on digital hydrogeological maps [17-22].
The main aquifer complexes and horizons of the region containing low-salinity water are the following
sediments: Alb-Cenomanian, Upper Cretaceous, Upper Miocene-Pliocene and eolian sands. Groundwater
of Alb-Cenomanian deposits is the most widespread and water-bearing among all aquiferous deposits in
the basin and represented by different-grained sands and sandstones with interlayers of clay sediments, and
come out to the day surface in Prekaratau valleys and in bottoms of some drainless depressions. Depth of
occurrence of underground water complex in the basin as a whole varies from absolute levels of 100-150 m in
the Prekaratau valleys to minus 800 m in the South Mangystau and Ustyurt. In the zones of outcrop of water-
bearing rocks the discharge of springs does not exceed 1.5-2 L/sec. With dipping of the stratum and with the
increase of groundwater head their productivity increases: in Prekaratau valleys self-discharge well flow rates
are 5-40 L/sec, in the south and north of Mangystau reach 40-55 L/sec. Water-bearing complex of Upper
Cretaceous deposits containing groundwater of marl-chalk sediments with mineralization up to 5 g/L is spread
in the region on the limited area. Such waters are uncovered within the North and South Aktau monoclines.
Flow rates of water points do not exceed 1-1.5 L/sec under small drops in water level. Here their salinity is
1.5-5 g/L. Water-bearing complex of Quaternary sediments with salinity up to 5 g/L is connected mainly with
uncemented and weakly cemented sand massifs and in some limited in area sections of marine Quaternary
sediments in the form of lenses and interlayers in clay strata. Weakly mineralized groundwater is established
in the northern part of Ustyurt, in the northwest of the South Mangystau plateau, as well as in different parts
of the Bozashi Peninsula. The Sam sand massif is the largest with a total area of 2320 km
2
in the northern
part of Ustyurt. The sand massifs of the northwestern part of Southern Mangystau (Sauskan-Bostankum,
Tuyesu, Baskudyk) and the Bozashi Peninsula (Kyzylkum, Zhilimshik, etc.) have small areas (150-500 km
2
each). The productivity of wells, laid especially in the sands in the north-west of Southern Mangystau and
Sam massif, varies from 0.2 to 6 L/sec at lowering the water level by 1.5-10 m. Mineralization of water in the
most part of massifs is mainly 0.2-1 g/L, and in their marginal parts and near salt depressions increases from
1.5-3 to 5 g/L. Weakly mineralized groundwater of marine Quaternary deposits in some parts of the central
upland part or in flat depressions of the relief, near lake and other depressions is revealed only in the South
and Central Peninsula Bozashi [23].
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