Geologically, all bitumen mines are located in the folded Zagros zone and Zagros formations such as Pabdeh, Gurpi, Asmari and Mishan are the hosts of Gilsonite mineralization.
Gilsonite mineralization is mainly formed in geological structures such as anticlines as well as contacts of various formations. Similar to oil, reservoir rocks, source rocks and masonry also play a role in Gilsonite mines. It seems that the presence of faults in some mines has caused the escape of light petroleum products and leaving Gilsonite in the faults.
In the analysis of this mineral, ash is the most important quality parameter of Gilsonite, which is a high quality Gilsonite with less than 10% ash.
Other important parameters are the amount of carbon, hydrogen, nitrogen and sulfur. The average ash content of Gilsonite mines in Iran is 15%.
In Iran, Gilsonite is a relatively rare mineral, the highest quality of which exists only in western Iran and the western city of Gilan.
As mentioned, Gilsonite mineralization in western Iran and geologically, are formed in the folded Zagros zone.
Numerous geological events such as sedimentation, orogeny, folding in the Zagros zone have caused this part of Iran to be of special importance from an economic geological point of view.
Among these, oil reserves are the most important. Existence of large arches with zigmoid shape is a feature of this part of Zagros.
The joints and fractures in these oil basins have sometimes caused the release of light petroleum materials and the retention of heavy petroleum materials (bitumen) in the oil basins and the formation of Gilsonite mines.
Geologically, most Gilsonite mines are formed in oil basins and in faults and fractures. It is also sometimes formed in folded structures as well as in contacts between different layers.
The host rock of mineralization mainly consists of gypsum, marl and clay units. Therefore, gypsum and marl units are important lithologically. On the other hand, the formation of Gilsonite reserves is often limited to faults and fractures in these rocks and the importance of structures such as faults, fractures, anticlines, synclines in the accumulation and storage of petroleum products is evident. Be.
These Gilsonite-containing fractures are more common in W-E to SE-NW processes. Therefore, the role of structures, type of structure, their process, the presence of faults and fractures in the formation of mineralization is of great importance.
In Iran, various geological formations such as Gurpi or Marni and Chile formations that are older than have the potential to produce petroleum products are the source rock of this mineral and on the other hand gypsum formations such as Gachsaran Formation and clay can be used as rock. Push act.
Also, anticlines and planed synchronies are the best structures for the accumulation of petroleum products. Therefore, despite the mother rock, reservoir rock, rock cover and suitable structures, the necessary conditions for oil formation have been created.
On the other hand, the presence of tensile structures such as faults and joints has caused fractures in the masonry, reservoir rock and also anticlines.
Therefore, lighter petroleum materials such as gas and oil are removed through the fault and heavy petroleum materials such as Gilsonite are embedded in the faults and tensile joints.
Therefore, in addition to the role of various formations in the formation of the oil basin, compressive and tensile forces have also been involved in the formation of mineralization, so that compressive forces have caused anticlines and synclines and faults and tensile forces causing lighter oil outflows and Gilsonite deposition in There was space between them.
In Iran, Gilsonite mines are found in limited numbers in the west of the country, especially in Kermanshah province.
Lithologically, all these mines are the hosts of the mentioned formations in Zagros.
Mineralization has occurred mainly in the form of masses and lenticular masses at the boundary of marl and gypsum units, as well as in faults, fractures and even karstic cavities and cavities, of which mineralization in the contact of gypsum and marl units has the highest volume. It is a mineral. These mines are extracted in open form as well as underground.
Conclusion :
According to the studies, it is clear that Gilsonite is a rare mineral in Iran and its extraction is very important due to its high value. The presence of important geological structures as well as related geological formations in the early stages of exploration is very important.
The host rock of mineralization mainly consists of gypsum, marl and clay units. Therefore, gypsum and marl units are important lithologically. On the other hand, the formation of Gilsonite reserves is often limited to faults and fractures in these rocks and the importance of structures such as faults, fractures, anticlines, synclines in the accumulation and storage of petroleum products is evident. Be.
