International Journal of Marine Science, 2017, Vol.7, No.3, 19-30
23
coast and the 400 meters’ depth is situated in the 5-6 km distance to the sea. The continental shelf in the Eastern
coast is very broad and extensive and its average width is about 130 km (Figure 5). The coast and seabed
roughness in north Caspian are covered with plain or precaspian land posts. In this plain, which is called novo
Caspian, there are traces of sedimentary terraces of marine deposits related to various surface levels of Caspian
Sea. In the south Caspian there are two marine troughs of Lankaran trough (with depth of 1025 meters) and Iran
trough (with the depth of 800 meters). In the middle Caspian, there is Derbent trough with the depth of 788
meters). It should be mentioned that Caspian Sea bed slope angles in the continental shelf are not high (about 6-7
degrees). Meanwhile, the pitch in the shelf slope area and seabed doesn’t exceed 30 degrees. In the west and south
of Caspian Sea, the seabed slope increases very fast, while in the east and north of Caspian Sea this process
happens slowly. The geomorphology map of Caspian Sea bed and coasts of (Figure 6) is one of the main figures
of this paper. In preparation of this map, the data of the three before mentioned maps and documents related to the
resulted analysis of geological and geophysical research on Caspian Sea troughs were applied. The
geomorphology map represents bed roughness of coastal zone and the present Caspian Sea shorelines. The
following shapes are defined in the map of the sea bed (it is not provided here): shelf, shelf slop and sea floor and
deep water depressions. The slope of the shelf is not greater than 30’ and its width is not the same everywhere
while the edge of the shelf has different depths. In the west and south of the sea it is 50-100 m deep. In the other
parts of the sea the shelf edge is 100-130 m deep. The edge of the shelf lies on the line that links points with slop
30’. After that the shelf slope starts that extends to the depth of 650 m. Then the sea floor begins where slopes
again decrease and do not exceed 30’. Sea floor is followed by deep water depressions. There are two depressions
in the Southern Caspian Sea: Azerbaijan depression–1025 m (the deepest one in the Caspian Sea) and Iran
depression that is around 800 m deep. In the Middle Caspian Sea, the depth of depression (Derbent) is 788 m.
Figure 5 The map of seabed main morphostructure
Figure 6 Geomorphological map of the seabed of the coast of
the Caspian Sea
