Geology Reference
In-Depth Information
We will now review the likelihood of a functioning elision system in the
Lower Miocene waterhead complex, which includes the Lower Miocene
Vorotyshchen Series (the Aquitaine and Burdigalian Stages) of gypsiferous
and salty clays with thin sandstone interbeds and conglomerate lenses; and
the Stebnik and Balich formations (of the Lower Miocene Helvetian Stage)
composed mostly of clayey rocks.
Lateral ground water flow under the elision water-exchange model sug-
gests the presence in the complex of sufficient conditions for forming a
relatively unobstructed outflow of squeezed-out fluids. These conditions
do not exist due to:
t
Mostly clayey section.
t
Sporadic development in it of thin lens-shaped reservoir
members.
t
Intense faulting of local highs causing their fault-block structure.
t
Skib-step structure of the entire region.
t
Common development of nonuniformly-compacted high-
porosity plastic clays with AHPP.
Tectonic and lithological factors create hydraulic isolation of reser-
voirs and their highly restricted discharge. This generates specific hydro-
dynamical environment in the upper hydrogeological stage of the region.
The distinctive feature of this environment is substantial potential energy
resources but not necessarily their realization. Because of this circum-
stance, the Lower Miocene waterhead complex is an elastically-closed step-
block natural reservoir with a quasi-stagnant water-exchange regime due
to the practical absence of ground water drainage.
The infiltration water-exchange is of no significant importance within
the reviewed complexes. This is shown by factors such as:
t
The involvement in the meteoric water charge of only lim-
ited areas over the denuded structures.
t
Drastic increase in ground water salinity to 140-270 g/l
already at depths of 300-500 m.
t
The discharge of the bulk of atmospheric agents through
surface springs, rivers and erosion network in the direct
vicinity of the charge area in the mountain and piedmont
zones (Kolody, 1983; Lozinsky and Bankovsky, 1972).
t
Tectonic cut-off of the infiltrates' waterhead generation
zones from the main reservoirs by the Beregovoy, Orlov and
other overthrusts.
