Evolution of earth`s crust and orogenic movements in Iran is not very clear,however in 1988 Timier has pointed out a great intercontinental rift occurred on the continent by name Pangea.It was separated into two continents N. Laurasia and S. Gondwana.The geologic data shows that Iran was on Gondwana lland until the late of Devonian(405000000) Then Saudi Arabia and Iran platform were separated.Each one created independent depositional basin.In the Paleozoic period,a series of vertical orogenic movements happened on Cambrian and caused sudden changes to be created in lithologic lands.
Eftekhar Nezhad an Iranian geologist and geomorphologist believes that on the Paleozoic period ,a series of erosions occurred in west Alborz mountain in Tabriz and Zonouz region.Also a lot of orogenic activities have been observed in the mentioned regions since Precambrian.Huber Rieben a French geologist,his studies were done on geology of Azerbaijan province in Iran.In 1935 ,he suggested that limestone deposits of Cambrian has lain unconformably on Devonian depositions.Reiben also pointed out the Hersinian orogenic movements that have occurred in Azerbaijan and some other part of Iran.He believed the collision of N.gondwana land with European continent resulted to this orogenic movements in Azerbaijan and Zonouz region.
Cretaceous:The orogenic movements of late cretaceous period caused the sediment basins gradually to rise from the sea.This condition was continued for the Paleocene period. Finally Zonouz region like other part of Iran emerged from the sea.On the Quaternary,some alluvial terraces have lain on the upper-level surfaces in comparing to the base-level.It implies that water erosion has occured in the region.Alluvial deposits in the upper part of river are coarse-grained size sediments whereas fine-grained deposits are accumulated in the lower part of river.The thickness of these sediments vary in different parts of river(from 40to 80 meters).
The formation of Eocene indicates that area was covered by shallow sea. after passing a long period of time, the tectonic and orogenic movements began created some faults.Two main faults were recognized on the river bed of Zonouz.They have extended N.W to S.W and N.E to S.W direction.(see geologic map)