مقالات

Study area is located in southwest of Birjand and in eastern part of Lut block. In south east of Nalino Tertiary igneous rocks (volcanic and subvolcanic rocks) such as andesite, pyroxene andesite, dacite and diorite porphyry are association with pyroclastic rocks such as tuff, breccia and agglomerate. Plagioclase, pyroxene, hornblende, biotite and quartz are the most phenocrysts of these rocks. Apatite, sphene and different iron oxides are accessory and sericite, chlorite, calcite and epidote are alteration minerals. The main texture in these rocks is porphyry with microgranular and microlitic groundmas, glomeroporphyry and poikilitic. The main mineral textures are sieve, embayed and zoning. Poikilitic, sieve and embayed texture in plagioclase are evidences of disequilibrium during crystallization of magma. Carbonatization, opacitization, chloritization and sericitization are common alteration in these rocks. Existence of secondary minerals such as iron oxides, malachite and azurite show that southeast of Nalino is important area for exploration of copper mineralization.

Shekasteh Divar area is located in east of Iran and northwest of Birjand. The area comprises outcrops of Eocene volcanics rocks (rhyolitic tuff breccia, andesitic tuff breccia and andesite), which was intruded by granotoid dykes (diorite porphyry and granodiorite porphyry). Mafic dyke (Gabbro and gabbrodiorite porphyry) is the youngest unit in area. Dykes have characteristic of high-K Calc-alkalic and Enrichment of LREE relative to HREE and LILE to HFSE. According to the evidence, magma was formed in post-collisional extension-related zone.

Based on structural divisions of Iran, the study area is in central part of Lut block on 1:250000 Dehsalm geological map, 30Km away of Southwest of Qaleh zari at Kuhsefid area. The rock units of this area include: volcanic lavas with Andesite, Dacite, Tuff, Green tuff that has a numerous outcrop in the vicinity of streams. Subvolcanic bodies include: Quartz diorite porphyry, Diorite porphyry, Pyroxene diorite., Tonalite and Granodiorite porphyry units which happened as a dyke into the Andesite units. They have Eocene age. The dominant texture in volcanic rocks is porphyry with microlithic groundmass and in the sub - volcanic unites, is granular with microgranular groundmass. They show a pervasive carbonatic alteration. Copper mineralization happened as veins within the andesite rocks which covered the East part of study area.

The Dezuki copper exploration area is located in the northeast of the city of Qain (South Khorasan province). In terms of the division of the structural zones of Iran, the Dezuki copper exploration area is located in the east zone of Iran and in the north-east of the Lut Block. Different rock units, including lava units (trachytic andesite, andesite and basaltic andesite), and pyroclastic (tuff and agglomerate) of Paleocene, and sedimentary units of marl and Eocene limestone and polio quaternary outcrops (conglomera and sandstone). The mineralization of copper is most commonly observed in volcanic units, especially in andesitic units, which include malachite, chalcocite, turquoise, neotosite and cherysocolla. Petrological studies show that the volcanic rocks of the region have arisen from parent magma of the alkalin calc and in a continental marginal tectonic environment.

nowadays , the use of satellite imagery in mining exploration can increase the speed of different projects.The time - consuming analyses of data that have been developed in person or by using old maps from large areas and over a long time have given their place to better analysis in terms of quantitative and qualitative terms as well as time.The use of these pictures also has a large scale of scale and large scale, and sometimes minimizes the cost of the project less than half in comparison to the classic methods.with all the benefits they have , they are not directly applicable and must be processed, which are used to process images in this regard. in this thesis, we have used ENVI software for image processing. the main objective of this research is to obtain a general view of the alteration of the gonabad region, which is obtained by image processing, including false color combinations, band proportions, and principal component analysis.These results led to the discovery of the argelice and proplitice alteration zone , which gives us an overview of the regions with potential in this area. It divides the wide range into smaller heuristic limits and will reduce the cost of the discoveries. it also explains the need for accurate and objective studies and providing a suitable exploratory model in this area.

This study was conducted in the 1:100000 rectangle sheet of Koodakan in the southwest of Birjand to detect the alteration minerals associated with porphyry and epithermal copper-gold mineralization through false color composites and Selective Principal Component Analysis (SPCA) using ASTER sensor images of Terra satellite. The images were processed after making necessary corrections and preparing mosaics. In the false color composite (RGB: 468), phyllic and argillic alterations were discriminated in red to white pink and propylitic alteration 157 in green. The analysis of SPCA were implemented on the bands 1, 4, 6 , 7; bands 1, 3, 5, 6 and bands 1, 3, 5, 8 for discrimination of argillic, phyllic and propylitic alteration respectively. Furthermore, SPCA on bands 1, 3, 5 and 7 were used for discrimination of alunite alteration. For greater discrimination of alteration zone, two color composites were made from the results of the SPCA. One false color-composite is made from 4th principle components (PC4) of alunite, argillic, and phyllic alterations, and the other one is made from selected Principle Components of propylithic, argillic and phyllic alternations. Bright pixels in the color composite image (high digital number value) indicate the presence of three alterations together. Comparing the results with the geological map, previous studies and different processing methods indicate the acceptable accuracy in detection of the alterations.

Several mineral deposits and indices have been reported in the eastern Iranian mineralization belt, which systematic exploratory studies have not been completed yet. The rectangle sheet of Koodakan's 1:100000 in the southwest of Birjand and eastern Iranian mineralization belt were investigated for detection of iron oxide mineral related to mineralization in this study. In order to reach this aim band ratio and Selective Principal Component Analysis (SPCA) techniques were implemented on OLI sensors of Landsat-8. The images were processed after necessary corrections. Comparing the results with the geological map, previous studies and different processing methods indicate an acceptable accuracy in the detection of iron oxide and gossan.

The study area is located in the north-east of Bojnourd. Hydroxid iron mineralization and clay minerals are sporadic in this area. The expanded units in this area include a sequence of Sedimentary rocks of Kopeh Dagh. The faults and geological structures in the Bojnurd region are compressed linearly. In this paper, by using color combining methods, bonding and main component analysis of satellite data, estrogen sensors of alteration and inorganic potentials of the region were identified.

The study area is in South Khorasan Khusf small province and near to the Aliabad village at the1:250000 Naybandan crossroad geological map, 1:100000 South of Sehchangi geological map. Nowadays remote sensing investigations is known the best method at deposit exploration because of having a data with wide and integrated view and different wavelength range and very low cost. Jafar e Hasani study area is the best place for remote sensing studies due to vast mineralization symptoms and presence of carbonatic and silicitic alteration with Aster and Landsat images.

Podiform-type chromite deposits in ultramafic sections of ophiolite rock complexes can be detected using remote sensing data. In this study, the host rock units of chromite (serpentinized harzburgites and dunites) are discriminated using Landsat ETM+ and Advance Space borne Thermal Emission and Reflection Radiometer (ASTER) satellite data in the Sabzevar ophiolite belt. For this, Different band ratios, log residual, Ninomiya index and principal component analysis methods have been applied for mapping the mineralization-related ophiolite rocks.Then, the areas of serpentinized harzburgites and dunites obtained from these four methods converted to polygon and merged for making an individual serpentine alteration layer. In the following, Fry Analysis was used to evaluate the output of the remote sensing and Spatial distribution of known deposits and also serpantinized areas were plotted.Due to the high coincidence of orientation between known deposits and serpentinized areas, it can be concluded that ETM+ and ASTER satellite data are efficient in identifying chromite mineralization regions. In addition, the results of remote sensing have a very good consistency with the geology map of the study area.