Geology Reference
In-Depth Information
2.2.2
The Indolo-Kuban Foredeep
Ground waters in the sediment cover penetrated by wells include all
hydrochemical varieties: sulphate- and hydrocarbonate-sodium, chlorine-
magnesium and chlorine-calcium. Their salinity varies within a wide range
between 4.7 and 247.2 mg-equiv. (1.3-70.7 g/l), the secondary salinity fac-
tor is 0.8-20.5%-equiv., the primary alkalinity factor is 0.3-65.0%-equiv.,
sodium/chlorine ratio =у = 0.86-5.31 (Tables 2.16, 2.17).
The major waterhead complexes are: the Upper Jurassic, Lower
Cretaceous, Upper Cretaceous, Paleocene-Lower Eocene, Upper Eocene
(the Kuma Fm. in the West Kuban Trough), Oligocene-Lower Miocene
(the Maikopian Fm.), Middle-Upper Miocene and Pliocene. Regional
water-barriers are Albian clays, Campanian and Maastrichtian carbon-
ate clays and compact marls, marly-clayey and clayey series of the Middle
and Upper Eocene (the Kutaisi, Kaluga, Khadyzhen and Beloglin forma-
tions in the West Kuban trough), Maikopian clays and clay members in the
Miocene and Pliocene (the Chokrackian and Karaganian horizons, Lower
Sarmatian sub-Stage, Ponthian and “ore beds” of the Kimmerian Stages).
Ground waters from the
Upper Jurassic
carbonate complex were
obtained at the Sergeyev and Moshkarev prospects. Their hydrochemical
type is hydrocarbonate-sodium. Total salinity is 20.8-45.2 mg-equiv. (5.0-
12.9 g/l), primary alkalinity factor is 42.7-45.2%-equiv., sodium/chlorine
ratio = = 2.53-5.31.
Ground waters from lenses of compact fractured argillite siltstone
and low-permeability sandstone interbeds in the clastic
Lower Cretaceous
complex were obtained at the Abkhaz, Suzdal, Stavropol, Medvedkov,
Maryev, Moshkarev and Tambov prospects. The water type is hydrocar-
bonate-sodium, total salinity is 25.3-42.6 mg-equiv. (7.2-12.2 g/l), the
primary alkalinity factor is 41.2-43.1%-equiv., sodium/chlorine ratio =у
= 2.50-3.15.
he
Upper Cretaceous
carbonate complex comprises fractured marls
and pelitomorph limestones with siltstone interbeds. At the Suzdal, West
Medvedov, Shumeysk, South Varenikov, Nizhne-Bakan, Moshkarev,
Kuybyshev and Fontanov prospects and in the Adagum and Kudako-
Kievsky fields are also encountered waters of the hydrocarbonate-sodium
type. Their salinity ranges between 21 and 38.5 mg-equiv. (6-11 g/l), the
primary alkalinity factor is 48.4-62.1%-equiv., sodium/chlorine ratio = =
2.91-4.07.
Typical feature of the ground water component composition in the
Mesozoic intervals of the region is an elevated sulphate content of up to
3.7-4 mg-equiv. (17-20%-equiv.).
