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0Impact Factor: SJIF 2021 - 5.81 2022 - 5.94
ГЕОГРАФИЧЕСКИЕ НАУКИ GEOGRAPHICAL SCIENCES
UDK 550.834.5.
TECTONiC OVERViEW OF THE SEDiMENTARY COVER OF NAKHCHiVAN
AUTONOMOUS REPUBLiC
VALiBAYOV ILKiN MEHMAN
Republic of Azerbaijan Ministry of Science and Education Natural Resources Institute
Seismological Service Department
Summary: The territory of Nakhchivan Autonomous Republic is tectonically complex, the sedimentary cover is represented by structural units called Sharur-Julfa uplift zone, Ordubad slope zone, Zangezur uplift zone and Nakhchivan derived depression.Depth partitions separating these building units follow them in different directions, dividing them into blocks, each distinguished by the variation in depth of the cover layer.
Key words: tectonics, cover, uplift, rifts
Nakhchivan Autonomous Republic covers the southwestern part of the Lesser Caucasus folded mountain system and covers an area of 5.5 thousand km2, from the north about 1.3 thousand km2 -the foothill plain area, 4.2 thousand km2 - forming the relief of the mountain range -from west to southeast It is 158 km, 75 km from north to south (at its widest point) and has the shape of an irregular rhombus. Orographically, the territory of Nakhchivan consists of high mountains, the unique Khachadag, Hanegah, Elinja, Nahajir, Arafsa, etc. It is surrounded by [1]. Extrusive dome protrusions on the Nakhchivan fault emerged as a border strip separating two tectonic regions (Lesser Caucasus, Central Araz depression region). Located between Iran and the South Caucasus microplates and reflecting a long history of geological development, the Nakhchivan Autonomous Republic is characterized by its complex structure and terrain diversity.
The geological structure of the sedimentary cover of the region is not tectonically homogeneous, it is represented by the following structural units (tectonic zones): 1. Sharur-Julfa uplift zone; 2. Ordubad bending zone; 3. Zangezur uplift region; 4. Nakhchivan derivative depression [2]. The composition of the geological formations that make up these zones, the characteristics of tectonic deformations, their ages and stresses differ from each other, and they consist of tectonic blocks of different sizes limited by depth fractures.
In the compiled seismotectonic map, structural units and the depth cracks that determine their boundaries appear as boundary strips.
The Sharur-Julfa uplift zone structurally corresponds to the northeast wing of the step-faulted tectonic blocks of the giant Maku-Marand uplift, which is located on the right bank of the Araz River and is generally oriented to the southeast. The geological structure of the zone includes the platform cover layer of the northern edge of Hondwana, the Devonian-Triassic shelf terrigen-carbonate
Impact Factor: SJIF 2021 - 5.81 2022 - 5.94
ГЕОГРАФИЧЕСКИЕ НАУКИ GEOGRAPHICAL SCIENCES
complexes that form folds complicated by fault and counter-fault uplifts as well as the overlying thin Jurassic-Upper Cretaceous Eocene complexes.
The Ordubad rift zone is bounded by the East Ordubad in the northeast, the Ashagi Araz in the southeast, the Havush - Anabadgadik - Nehrem deep faults in the southwest, and structurally corresponds to the rift-origin southeastern segment (tectonic block) of the Yerevan - Ordubad subduction. It is located mostly on the territory of Armenia and its northwestern flank is covered by the volcanogenic layer of the Lower Pliocene. The geological section of the zone includes the Upper Cretaceous-Paleocene aged carbonate-continental complex, Eocene aged basalt-andesite-dacite volcanics and Oligocene aged volcanic-sedimentary layer.
The Zangezur uplift zone is structurally divided by the Middle Eocene-Early Miocene Mehri-Ordubad granitoid batholith, which forms the southeastern part (tectonic block) of the Miskhana-Zangezur uplift, located mainly in the northeast on the territory of Girratag, Armenia. Araz in the southeast and East Ordubad in the west and northwest are bordered by deep faults and respond to the double-arched horst uplift.
The Nakhchivan basin is represented by the northwestern (Sharur) and southeastern (Julfa) parts isolated from each other. The northern side of the zone is bordered by the Nakhchivan deep rift, and the formation of the depression is associated with movements along this rift.
LiTERATURE
1. Geography of Nakhchivan Autonomous Republic, volume I. Physical geography, Acemi publishing house, Nakhchivan - 2017 p.37-38
2. Sh.A.Babayev, T.N.Kangarli, A.B. Mammadov "Stratigraphy of the Nakhchivan Autonomous Republic". Baku 2016 p. 6
