GilanGarb Natural Bitumen Formation is one of the most important organic substances in the earth, which play an important role in the construction of rock masses and other geological processes. Shek Maidan-Gilangharb area is one of the areas where natural bitumen has been investigated. In this article, the formation of natural bitumens, their geochemistry and their characteristics in Shek Maidan-Gilangreb region are discussed.
Natural bitumens have unique properties due to their formation in special conditions and complex chemical processes. For GilanGarb Natural Bitumen Formation, crude oil must remain and be separated from it naturally in suitable geological conditions. These conditions include sufficient pressure, suitable temperature and sufficient organic matter in crude oil. In Shek Maidan-Gilangreb area, these conditions are provided due to the presence of clear rock masses and high pressure in this area.
This mineral includes various organic compounds in which there are elements such as carbon, hydrogen, oxygen, sulfur and nitrogen. The geochemical investigation of bitumens in Shek Maidan-Gilangharb area showed that these bitumens contain compounds with a high percentage of carbon and hydrogen and also contain elements such as sulfur, nitrogen and oxygen.
These bitumens are found on the surface of the discontinuities and under the mass gypsum of Gachsaran Formation. Geochemical studies and elemental analysis of gilsonite samples show that oxygen values range from 3 to 38% and carbon values from 40 to 90%. The maximum amount of SiO2 and CaO is high in some samples and the amount of sulfur is also consistent with the high amount of CaO.
The amount of ash in the samples with variations of 2 to 19% indicates their quality. The percentage of volatile substances varies between 5 and 35% and they are of high quality. In addition, the moisture content of the samples varies between 2 and 37% and the quality of natural bitumen increases with its decrease.
Natural bitumens have characteristics such as high adhesion, heat resistance, resistance to dissolution in water and high flexibility. These characteristics have made bitumen a suitable material for use in industries such as road construction, construction and production of waterproof materials.
To study the formation of natural bitumen, 60 petrological and geochemical samples were collected in areas containing bitumen. To collect the sample, it was tried to represent all the veins as much as possible and not to take samples from the surface of the veins. Also, it was tried to take sampling in a condition that is less exposed to atmospheric factors. The collected samples were packed in plastic bags and 10 of them were sent to Iran National Steel Industrial Group for XRF analysis, the results of which are presented here.
Natural bitumen may exist in areas where geological and topographical conditions are suitable. These bitumens are divided into three groups: newly mined outcrops or in the process of being mined, outcrops which are widely outcropped and easy to identify, and outcrops which are partially outcropped and according to the evidence, it can be shown that they are rooted.
To search for natural bitumen, the depth of weathering in rocks that are exposed to direct sunlight is considered. Hydrometry and specific electrical resistance studies are also conducted to discover natural bitumen.
Natural bitumen in Gilangreb region and Shek Maidan region has been seen in the form of lenticular masses with thicknesses of several centimeters to 10 meters due to construction activities. Some natural bitumen deposits can be seen in Shek Maidan area in the form of streaks with different thicknesses and several meters long.
The chemicals in Gilane gharab natural bitumen may include compounds such as aromatic and aliphatic hydrocarbons, cyclic and saturated hydrocarbons, organic acids, aldehydes, ketones, phenols, metal slag, amines, alcohols and other functional groups. The amount and type of these compounds depends on the place and conditions of bitumen extraction and may be different in other bitumens.
According to the study of GilanGarb Natural Bitumen Formation, geochemistry and their characteristics in Shek Maidan-Gilangreb region, it can be concluded that these bitumens have organic compounds with a high percentage of carbon and hydrogen and have properties such as high adhesion, thermal resistance, and resistance to dissolution in water. and high flexibility. These characteristics have made bitumen a suitable material for use in industries such as road construction, construction and production of waterproof materials.
In the studied area, outcrops of natural bitumen, whose pattern is influenced by tectonic factors and folds, are found under the Gypsums of Gachsaran Formation and in their seams and cracks in the form of mineral veins. The studied area has suitable stratigraphic and tectonic conditions for the formation and occurrence of natural bitumen.
The amount of carbon in the analyzed samples varies from 40 to 90%, and the highest amount of volatile substances in the studied samples is about 35%, which indicates their high quality. XRF studies show that the amount of SiO2 and CaO in some samples is high, which may be due to the formation of these materials in gypsum formations, and a solution should be thought of to remove them.
