Geology Reference
In-Depth Information
Figure 2.13
South Caspian Depression. Sulphate content vs. depth:
I.
East flank of the
Caspian Depression,
II.
West flank of the Caspian Depression.
aforementioned association of sulphates with the hydrocarbonate-sodium
water type; on the saturation of rocks in local structures with mixes of the
syngenetic chlorine-calcium brines and the invaded alkaline waters; on
the patterns in the spatial distribution of the latters, etc. (see below), it is
believed that the main mechanism of the SO
2
−
ion occurrence and accu-
mulation in the water medium is the injection into the Middle Pliocene
complex of foreign sulphate-bearing waters (Rachinsky, 1973; Rachinsky
and Aliyev, 1973).
In parts of the section where formation temperatures do not block the
thiobacteria life activity, the sulphate-ions in the formed water mixes are
reduced and removed; in those parts with temperatures above 70-80°С
they are preserved and cause the functional association with the evolution
of temperature parameters and with the extent of injection of the underly-
ing waters.
The feasibility of the described mechanism in the environment of the
South Caspian Depression is substantiated by experimental studies. These
studies established increase in the sulphate concentration in the course
