482 
Tersk-Caspian basin from the south Caspian depression. This zone 
is made up of a chain of folded geological structures associated with 
the rich Apsheron and West Turkmen hydrocarbon provinces, includ- 
ing such large offshore fields as Neftianyye Kamni, Zhiloy Island, 
Zhdanov Bank, Cheleken, and others. The oil and gas in this province 
are in middle Pliocene deposits.* 
The south Caspian basin is a deep depression containing more than 
20 kilometers of Mesozoic and Pliocene to Quaternary deposits. It 
contains the Baku Archipelago fold belt on the west in which large 
oil fields have been discovered and which is a very promising area 
for further exploration. The Turkmen shelf on the east of the south 
Caspian basin is also considered a most favorable prospect. It contains 
Pliocene to Quaternary sedimentary deposits folded into broad gentle 
uplifts. In this stratigraphic section, middle Pliocene sediments are 
considered to be the mosi prospective.® 
4 Ibid. 
> Ibid., p. 240. 
FIGURE |. 
[Geologic time scale] 
Duration _, 
in millions Millions of 
of years years ago 
Era, period, and epoch (approximate) (approximate) 
Cenozolc: 
Quaternary: 
Recent Saas. ese te Ps weet ee. ee ced apa Py ea (‘) (4) 
| PALEN Sievers) (ch Le RS Cn a ee fe 2.5 2.5 
Tertiary: 
Bhogene «ts. A297) . 20) Ree) OTE So SOU 4.5 7.0 
MiIOGenG eat = iis = etrrsstn ew _ 44 . seep Sob ee ay fey D. 19.0 26.0 
MOU PORSN tie Pe ek OES ee eee 12.0 38.0 
BOCETER On ea ae!) mee teen ee. tonnes OMe By Aap e ree Oe 16.0 54.0 
IpaleGGene: Hees ae: Theale: | eee | epeesoe A eet Seeh 11.0 65.0 
Mesozoic: 
Gretacequepys rate. 4 Se a ee eee! 71.0 136.0 
Jurassic Pet Fae aE sk. ease We FO ARES SOE ene 54.0 190.0 
niassich sh, oy. sso icke Bry kee rser panes! Y bob ay late pas Lug apie 2 35.0 225.0 
Paleozoic: 
Permian 2-2 Mpa es age Ee 8k hp pel Sete Sg ene 55.0 280.0 
Pennsylvanians 262 - 22S O2G I. eee 7 ri ees Ty Rice: 45.0 325.0 
Mississippian __ ____ __ ea Se ee ag See Foe a 20.0 345.0 
IDCVONIAT YS -— 7c = te Saad, eae Beng tees eee ee ee | 50.0 395.0 
Silurtan*“*V4a U4 ot st he Bi SA RE Bee, ie PGi 35.0 430.0 
OrdoyitianwMitava. «3- eee _ So rerie gh f. bye) nieve nal pt 70.0 500.0 
(Cam brane. feo en aS” PM EGET 2k ge eis 70.0 570.0 
PregamiOnanss rt op ne eee ee ee en De Neen ae 4,030.0 4,600.0 
1 Approximately last 5,000 years. 
Note: Formation of the Earth’s crust about 4,600,000,000 years ago. 
Source: Adapted from McAlester, A. Lee. ‘The History of Life.” Prentice-Hall, Inc., 1968, p. 152. 
Note: The rocks of the Earth’s crust are divided into four major eras of time 
as shown in the above scale. The three younger eras are further divided into periods 
and spochs. The Precambrian, the longest and oldest era, witnessed the beginning 
of life and the evolution of simple plants and animals. The Palezoic Era was dominated 
by the invertebrate animals and fishes, the Mesozoic by reptiles (dinosaurs), and the 
Cenozoic by mammals. Commercial oil and gas deposits can occur in rocks of Paleozoic, 
Mesozoic, or Cenozoic age. The best prospects vary in age from region to region 
depending upon local geologic conditions. In general, Mesozoic age rocks (Triassic, 
Jurassic, and Cretaceous) are considered to have the best oil and gas potential on 
the Soviet continental shelves, with Paleozoic age rocks (Cambrian, Ordovician, Silurian, 
Devonian, Mississippian, Pennsylvanian, and Permain) considered to be next in im- 
portance. 
