Analysis of Fault Status in Qazvin-Rasht Railway and All Geological Stresses in this Area

The construction of Ghazvin-Rasht -Anzali railway is one of the major infrastructure projects and economic, social and political projects in the country, which facilitated access to the northern cities and ports of the country and the northern Neighborhood, and dramatically transformed the growth of the northern regions and Northwest of Iran. The study area is part of the Alborz orogenic skeleton, which, like other parts of the Alborz Mountain Range, is severely damaged and has fractures of fault, fall, slip and thrust. As a result of the formation of fracture, anticline and syncline in various sedimentary rocks and facies have been created. Detailed observation and field study lead to recognizing 21 rock unit or rock type in the studied area. This rocks and sediment dominantly composed of igneous rock (lava and pyroclastic) and sedimentary rock (conglomerate, sandstone, limestone and evaporates) with often Cenozoic (especially Eocene and Quaternary) age. Faults in the large parts of the area with two E–W (related to Arabia -Eurasia collision or N-S compression) and NE–SW (related to clockwise rotation of South Caspian Basin (NE-SW compression)) strike have been recognized. Frequent joints show NW-SE and NW-SE trend which can be related to N-S compression and NW-SE extensional axis, respectively. Result of this study show that in the under construction area of Qazvin-Manjil railway (a part of Qazvin-Rasht railway) there are a large number faults and fractures which for any construction should be considered.

کلیدواژه ها:

Alborz ، fault ، Stratigraphy ، Tectonic ، Backarc basin ، Caspian Basin