Geology Reference
In-Depth Information
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Figure 5.3
South Caspian Depression. Neftyanye Kamni structure. Evolution stages:
I.
By the end of deposition of the lower group of Production Sequence (Middle Pliocene),
II.
By the end of deposition of the upper group of Production Sequence,
III.
By the end
of deposition of the Upper Pliocene,
IV.
By the end of deposition of Tyrkyan Horizon
(Quaternary),
V.
Present-day.
The field is a typical diapir (Figure 5.3). Paleo-structural analysis indi-
cates that during Late Pliocene it was a relatively low-angle (10-20°) anti-
cline. The currently exposed Miocene beds were positioned at depths
deeper than 2,500 m. By the specified time the
Miocene-Paleogene deposits had substantial AHPP reaching at
2,500-3,000 m the value of 50-60 MPa. A testimony to it is in particu-
lar their significant current manifestation after large load alleviation from
these deposits.
Early in Quaternary, after a regional regression in the basin and subse-
quent denudation of the structure, 1,000 meters of the entire crestal por-
tion of the Neftyanye Kamni structure (as well as of many other similar
structures in the region) was eroded. This deep erosion caused the decline
