Geology Reference
In-Depth Information
The following conclusions were made regarding hydrochemistry of
waterhead complexes in the sediment cover of the Indolo-Kuban trough:
t
Minimum ground water salinity values (to 2 g/l) under the
sulphate- and hydrocarbonate-sodium water type belong
to the environment of present-day infiltration of mete-
oric agents. In the chlorine-calcium water medium the
maximum salinity value (up to 70.7 g/l) is the hydrochem-
ical background in the zones and areas of impeded water-
exchange or absence thereof. Sporadically encountered
“transitional” varieties are recorded where the alkaline and
hard waters mix.
t
In the Cenozoic section the vertical hydrochemical zoning
in hard waters of regional background complexes is normal.
Down the section the salinity and metamorphism of the
chlorine-calcium formation solutions and secondary salin-
ity factor values continuously grow respectively from 200
mg-equiv. (57.1 g/l) and 8.5%-equiv. In the Pliocene to 247.2
mg-equiv. (70.7 g/l) and 20.5%-equiv. in the Paleocene-
Lower Eocene complex.
t
Vertical hydrochemical zoning of the entire penetrated
Meso-Cenozoic section is generally inversed. Down the
section high-salinity (62.4-70.7 g/l) chlorine-calcium (sec-
ondary salinity factor 7.1-20.5%-equiv.) formation mixes
of the Cenozoic complexes' hydrochemical background
are replaced by regionally developed low-salinity (5.9-12.9
g/l) high-alkalinity (primary alkalinity factor 41.2-62.1%-
equiv.) hydrocarbonate-sodium Mesozoic waters.
t
Drastic increase is recorded in all Cenozoic complexes in the
salinity of chlorine-calcium waters of hydrodynamically iso-
lated (stagnant) reservoir zones (in the trough's flank areas,
regional reservoir pinch-outs, fault-restricted anticlinal
belts, flanks, fault-blocks and areas of local structures.
t
In the highest clay content Upper Eocene and Oligocene-
Lower Miocene complexes is recorded a ground water
salinity decline and simultaneous alkalinity increase (up to
reverse from the chlorine-calcium type to hydrocarbonate-
sodium type) from the flanks to the center of the trough.
This forms (at the total salinity values 25-30 g/l and primary
alkalinity factor 10-22%-equiv.) the present-day alkaline
hydrochemical background in the most subsided areas.
