Geological survey report in scale of 1:20,000 & geochemical Area or Sohrein- Degah North of Zanjan

States ZANJAN
Author Consultant engineering or Tehran- Padir
Published At 13 March 1992

Summary

This report is explanation of the map in scale of 1:20,000 in north of Zanjan area (Sohrein- Degah) that is located in a distance of 25km from northern Zanjan province. Geological precise collection in an area of 75 km2 is done & surveys on the earth & lab has been represented in this report with geological map in scale of 1:20,000.

Description

Abstract This report is explanation of the map in scale of 1:20,000 in north of Zanjan area (Sohrein- Degah) that is located in a distance of 25km from northern Zanjan province. Geological precise collection in an area of 75 km2 is done & surveys on the earth & lab has been represented in this report with geological map in scale of 1:20,000. The heights in this area contain Chelle-Khane Mount., Dash Sandestan & Ghare Dash which follows the general trend of Tarom Mount with a trend of NW-SE. The Chelle- Khane Mount. with a height of 2,885 m , in eastern end of the region, is one of high points & the lowest point of the region is around Sohrein village with a height less them 1,820 cm. this region is mountainous & has a mediate mountainous weather. There are scattered village in the region & ? resources of spring & permanent rivers & flume. The inhabitants are used to husbandry & agriculture. The studied area from geological aspect is a member of Zanjan quadrangle which is located in small part of western Alborz zone and in Tarom Mountains most it has special characteristics in geology (stratigraphy, geomorphology & tectonic) viewpoint. Relatively much thickness of igneous & pyroclastic rocks which comprise oldest rocks in the region & they are related to Eocene, they are of characteristics of this zone in this region (Tarom Mount.). The set of these rocks have been located under effluence of folding & tectonic after Eocene, especially lore phase of Alpian phase & it rehears dominant morphology of the region. The present formations in the region that oldest ones are related to Eocene period & newest ones to recent sediments, containing Eocene volcanic & pyroclastic, oligocence intrusive rocks & Quaternary sediments which have extension in the region. The major formation which is present in the region in a big part, is a much thickness of pyroclastic & volcanic rock as a part of Karaj fm. Small out crops of intrusive rocks is present in this are a that an of them have origin from a relative big batholite & parts of that have exposure in some have which can be attributed to Oligocene. Quaternary sediments of now have much development in the area are limited to a few terrace out crop & young alluviums & deposits of river bed. Copper ore deposits of the region are type of hydrothermal & reason of this mineralization is intrusive masses containing of mineral - bearing hydrothermal solution & locating of that adjacent to volcanic & pyroclastic rocks of Karaj Fm. The minerals present in this ore deposits are as follows based on studies: Chalcopyrite (CuFeS2), Malackite (Cu2Co3CoH2) , Bornite (Cu5FeS4), chalococite (Cu2S) , covelite (CuS), hematite (Fe2o3), pyrite (FeS2), Azurite Cu3 (Co3)2(OH)2 & limonitc (2Fe2o3, 3H2o) that are seen as filling of fractures with streak & small streak structure as irregular & discontinuous. Metamorphism in fracture walls is in type of propillitisation & main alteration is epidotizotion & silicification. What it is considerable in economic viewpoint, is origin & type of formation of these ore deposits which have been studied in west & east of studied area. This problem is a good reason for more studies of these regions. The maximum carat of copper (Cu) is 7.35%. it can be said that in carried out tests in method of chemical decomposition, inside of sampler, 70-Z-38, element of silver (in amount of 188 ppm) has been reported which has special importance in geological view point. So it is necessary more precise surveys be carried out with more extent & consideration & for obtaining move information about west & east of the region which have the potential of copper, we need to prepare of geological map in a scale of 1:5,000 & in necessary case, drilling of transactions, bore holes & exploration tunnels & geophysical gatherings. Geochemical surveys indicates that scattering of metal elements in rocks in whole region is higher than international base level of similar rocks & hence trace& evidences of copper is as secondary minerals such as malackite & azurite, can be observed in whole region. Two zone n east & south of the region, zones I& II indicates being suitable of unit Ekkv1 for copper, lead, zinc, barium & strontium & it explain that mineralization whose areas are polymetal. Zones I & II indicates very much concentrations of race elements too what suggests explanatory & semi-explanatory surveys in mentioned zones.

tags: ZANJAN