JOURNAL OF EARTH AND RESOURCES
Year:2010 | Volume:3 | Issue:2 (7)|Papers Count:8

Dez flow dam Site has located on Zagros folded belt. Khalaj, Pirahmad and Dezfol faults are the most important seismic sources in this area and they should be considered accurately. Khalaj fault is a capable to generation of big earthquakes (M>7). Maximum horizontal and vertical acceleration of Predictable earthquake on this fault is 0.697g and 0.618g respectively by deterministic approach. Also, according to probabilistic approach, maximum horizontal acceleration for 150, 475 and 2000 years repeat times are 0, 234g, 0.273g and 0.331g respectively.

The area under studing is situated at 55 km east of Ardabil County, in the structural zone of western Alborz. There is a vast volume of volcanic Eocene rocks with a varity composition of andesit, basalt, Rhyodacit and tuff combination, so that volcanic andesit rocks and andesite megaporphiritic have a more expanded volume, in comparison with other rocks. In the mentioned area, mining is the form of vein, veinlet and open space filling. According to the mineralography mineralizing of the ore deposit, consist of Native Copper, Malachite, Chalcocite, Covelite and Cuprite. Mineralization in this ore deposit is controlled by faults. Considering the kind of host rock that is Andesit and megaporphritic Andesit, and based on the form of mineralizing and mineral paragenesis, mineralizing in the studing zone is probably in accordance with the modle of Andesit type of Copper, by hydrothermal solution which is originated from megaporphritic Andesit.

The study area is the 1: 50, 000 sheet of Alishar in the northwest of Markazi province, northwest of Saveh and near to Razeghan County. In this area, 170 geochemical samples in the size of 80 meshes were taken from stream sediments. Factor analysis by Pearson method was used to investigate enrichment of Au and its pathfinders and as result the anomaly map of Au and its pathfinders was compiled. Four anomalous areas were indicated by factor analysis method for Au exploration, in which the forth area attained the highest priority among others that is located in the north of the area. Lithology of the area includes granodiorite, monzonite and ignimbrites of acidic to intermediate composition. These ricks enclosed by sedimentary units such as sandstone, shale and limestone and also by tuffs.

In the mouth and margin of the Sefidrood river, black sand deposits containing heavy minerals is visible. Field Studies and sampling show that the amount of these sediments gradually decreases from the mouth of the river to upstream other insofar as their effect is not seen so that in the mouth of the river, in the Caspian Sea margin (Delta Sefidrood in Kyashahr) have maximum frequency and in the Rudbar reach to minimum. Based on stereomicroscope studies constituent components of these sediments are: heavy minerals basically titan magnetite, hematite and black ilmenite with quartz, biotite, pyroxene, amphibole, calcite and feldspar. Chemical analysis of these sediments revealed high amounts of TiO2, Ce, La, Ga and Hf in them from this point have chemical similarity to alkaline gabbros mass of region, therefore, it seems that these gabbroic mass are Source of the Sefidrood river black sand deposits. Considering the normative composition of sample and FeO-TiO2-Fe2O3 triangular diagram, their combinations are similar to series of hematite–ilmenite. In which part of the Ti has been entered in the building of Magnetite in which case magnetite contains of Titan can be applied. Based on Laboratory studies, these minerals have formed simultaneously with the formation of Silicate minerals from a magma containing 0 to 12 percent TiO2 and in 1954°C. Titan oxides in the studied black sand are exolusion phase of magnetite and ilmenite that cannot be separated with today modern equipment.

There are many thermal springs in Ramsar area at the north of Iran, having therapeutic properties for high concentration of sulfate, calcium, and radon and have been in use from the long for treatment of disease such as Rheumatism, Dermatologic and digestive complications. On the other hand, Ramsar is one of residential areas through the world having naturally high radiations (HNLRA) (High Level Natural Radiation Area). In this regard we can name Yangjiang in China, Kerala in India and Guarpari in Brazil. In Ramsar area the annual radiation is 260 mGy y-1 while the radiation rate is 10 Gy y-1 for its 2000 population. The reason for such radiation may be allocated to high radium rate in available thermal springs, rocks and soil of Ramsar area. For thermal springs in the area and usage of radiating rocks in residential and administrative buildings, settlers in the area are subjected under radiations from radium and isotopes from destruction of radium as well as high rate of radon (more than 1000 MBqm-3). Some believes that there is a linear, no-threshold relation between radiation rate and carcinogenic effect, while no such definite effect has been found yet in Ramsar area and all HNLRA areas. So more and through studies are require on the subject. In this research work we have studied the relationship between natural radiations from the springs and radiating materials used in buildings with different disease and therapeutic and healing effects of Ramsar thermal springs.

Tuzgi area is located 60 kilometers southeast of Zahedan, in Eastern Iran Flysch Zone (Nehbandan-khash Zone). Geologically, the study area is covered by flysch deposits and intrusives rocks of different size and mainly of granodiorite composition. The study area consists of high-angle faults of different sizes with general trends of north-east and south-west, along which stibnite mineralization occurs. Based on thin section studies, the most important minerals of these rocks are quartz, biotite, plagioclase and k-feldespar. Stibnite is the most important ore mineral. Fluid inclusions are of primary type and spherical in shape. The melting temperature ranges between -3 to -20 degrees Celsius and the salinity is variable from 0.18 to 7.86 wt% NaCl equivalent to halite weight percentage. Based on above data it is concluded the genetic type of ore-mineralization coincides to low sulphidation of epithermal type.

The study area (Abtorsh) is located in the western part of Central Alborz, in northwest of Qazvin. The area is a part of Tarom geostructural subzone which is contained Eocene subaerial and submarine volcanic rocks, Neogene conglomerate and Quaternary deposits. From stratigraphy viewpoint, the volcanic rocks are equivalent with Karaj formation in the Central Alborz and their age has been considered Middle to late Eocene. The volcanic rocks almost exclusively have been suffered hydrothermal alteration and therefore the assumption can be considered very unlikely that the formation of alteration zones in the area was caused by Tertiary volcanism with syn- and post-volcanic hydrothermal fluids activation. The hydrothermal alteration zones which are exposed in the Abtorsh area include propylitic, argillicalunitic and silicic alterations that from viewpoint of intensity and vastness the argillic-alunitic alteration zone has a special significance in the area. The argillic-alunitic alteration is formed in acidic tuffs and contains three parts which are included in a vertical sequence from bottom to top, respectively serisitic-argillic, argillic-alunitic and silicic. Mineralogical studies conducted on samples taken from different parts of argillic-alunitic alteration zone showed that each of the three parts is formed from different mineral assemblage. Thus in the serisitic-argillic part: serisite-quartz-pyrite-montmorillonite-gypsum±kaolinite±K feldspar±anatase±alunite; in the argillic-alunitic part: kaolinite-alunite-quartz-montmorillonite±jarosite and in the silicic part: quartz-alunite-kaolinite±montmorillonite were identified. Geochemical studies and trace elements behavior showed that argillic-alunitic alterations in the studied area are comparable with acid sulfate or high sulfidation epithermal alterations which are formed in the hydrothermal magmatic or hypogene environment.

The potential of Bardaskan’s gold is located in Khorasan razavi and in the central domain on the volcano plutonic belt of north of Daruneh fault. Mentioned deposit is a part of Taknar zone. Some of the units of upper and lower parts of Taknar formation in this area have outcrop. The igneous rocks of this area involved rhyolite and rhyodacite are related to the lower part of Taknar formation and volcanoclastic rocks involved tuffaceous sandstones and also metamorphic rocks of this area involved shist and filit are related to upper part of Taknar formation. The mineralization in this area has been seen in two forms of veined and dispersed (disseminated). The mineralization in form of veined has been occurred in the fractures and faults and has seen in form of the veins of quartz and quartz-sulfide that in the quartz-sulfide veins, sulfide frequently is chalcopyrite and occasionally pyrite. The mineralization in form of dispersed also has seen in form of distributed inside the altered host rocks (the metamorphic tuffaceous sandstones and shists) of this area. Based on the studies of the fluid inclusions, isotopic and other witnesses discussed in this paper, could introduce the gold deposit of Bardaskan area similar to the epithermal low sulfidization type gold deposits.