Tectonics and structural geology of Gorgan and Aliabad area

Category Tectonic & Seismotectonic
Group GSI.IR
Location The 3 Symposium of Geosciences
Holding Date 31 July 2007
Abstract :

The studied area is located in the part of Eastern Alborz. Based on Division of Iran into the various structural zones, the southern half of area is situated in the Alborz and Gorgan -Rasht zones that are separated from each other by the north Alborz Fault. Northen half of the area is located in kopeh-Dagh zone that is separated from the Gorgan-Rasht zone by the concealed Khazar Fault. In the studied area the significant results ,including:

- The dolomite of soltanieh Formation is the oldest rock.

- It looks, Gorgan schists and volcanic schists in Aliabad are in sequence, comparable and equivalent the upper Ordovician rocks and Soltan-Meidan volcanics(Silurian) in the north of Necarman village.

- In Gorgan – Rasht area, There is an abvious Angular unconformity between Mesozoic deposits (Shemshak.F) and older rocks

Altogether, the Paleozoic rocks in the Alborz and Gorgan-Rasht zones, in spite of facies changes in some formations and local stratigraphic gaps, have shown a single sedimentary basin before Mesozoic, Besides, It appear that Continuation of this Basin towards the Gorgan plain (Kopeh-Dagh zone),has been cut by big khazar Fault ,this cut and uplift of the northern limb of remains of Gorgan schiest Antiform (North of Gorgan – Rasht zone), Nearly synorogenic of Early kimmerian. It is initial for starting separation sedimentary environment in the two Kopeh-Dagh and Gorgan-Rasht zones. Recent zone is actually the part of Alborz zone in which there is a higher deformation than Alborz zone, specially in the northern parts of that (with approaching the place of collision of Touran and Iran plates).