Economic Geology
jahangir esmaeili; ahmad khakzad; mansor vosoghi abedini
Abstract
This area has been located in a scene ETM No. 164-37 and ASTER linear band prediction satellite image No. AST-L1A:002:ASTL1A 0108220733380109011021. Such measured images in different band combinations will be used for extracting of geological structures and types of alterations (iron oxide, Argillite ...
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This area has been located in a scene ETM No. 164-37 and ASTER linear band prediction satellite image No. AST-L1A:002:ASTL1A 0108220733380109011021. Such measured images in different band combinations will be used for extracting of geological structures and types of alterations (iron oxide, Argillite and Carbonate) and for detecting different stones and minerals of the ground, a spectrum range of 1.5 to 2.5 μ is very important.This range includes short to average IR range covering six linear band predictions (SWTR bands). On the other side, to use spectral reflectance curves of such minerals in USGSENVI spectral library for spectral analysis, it is necessary to resample the curves to the spectral range of ASTER. Linear Band Prediction methods, LS-Fit, Matched Filtering and BandRATIO used of ASTER images for all Minerals and iron alterations and for iron oxides there were also used visual interpretations and ETM images were used in band combination of RGB:531. Considering the petrological and geological situation of studied area (Scale 1:25000 of Kamoo), the type of Alteration and its index minerals detailed as below; Alteration of iron (Gotit, Hematit and Jarosit and Limotit), alteration of Argilic (Kaolinite, Motmorilonit, Ilite and Haloysite) and carbonate (Calcite and Dolomite) have been considered. Alterations present in remote sensing studies are in conformity with field and results obtained fromtypes of analysis conducted.
Remote Sensing
Seyedeh Sakineh Mousavi; Mehdi Honarmand; Hadi Shahriari; Mahdiye hosseinjanizadeh
Abstract
Mineral exploration in Esfandagheh area, located in south east of Kerman province is complicated due to verity of metallic deposits including volcanogenic massive sulfide copper, skarn iron, and volcanic manganese. This research was carried out with the aim of defining a model for mineral exploration ...
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Mineral exploration in Esfandagheh area, located in south east of Kerman province is complicated due to verity of metallic deposits including volcanogenic massive sulfide copper, skarn iron, and volcanic manganese. This research was carried out with the aim of defining a model for mineral exploration and providing mineral potential map using remote sensing data. ASTER and OLI images along with various image processing techniques including color composite of band ratios, principal component analysis (PCA), and QI and SI indices were applied to recognize the hydrothermal alteration halos. Result validation was done through field and laboratory studies. Argillic, phyllic, propylitic, and iron oxides/hydroxides alterations were enhanced using color composite ratios of ASTER bands like (B4+B7)/B6 in red, (B4+B6)/B5 in green, and (B7+B9)/B8 in blue. Hydrothermal alteration mapping was also accomplished using selected PCA of OLI 2, 4, 6, and 7 bands, ASTER 4 to 9 bands and a combination of OLI 2 and 4 bands along with ASTER 4 to 9 bands. ASTER thermal infrared bands applied to determine QI and SI indices for enhancing silicic halos. Mineral potential map was produced through integrating alteration maps by fuzzy logic method in which seven areas were identified such as Sargaz Kuh copper mine, Hossein Abad manganese mine, and Esfandagheh iron mine. Results showed the possibility of establishing mineral exploration model and producing mineral potential map in reconnaissance and prospecting stages using appropriate sensors and image processing techniques.
M Maanijou; N Puyandeh; A.A Sepahi; S Dadfar
Abstract
The study area is located at 42 km NE of Qorveh city, in KordestanProvince and in the Metamorphic– Magmatic Sanandaj-Sirjan Zone. There are other important gold mines such as the Zarshouran and Aghdarreh mines in this zone. The most important alterations of the region are sericitic (phyllic), argillic, ...
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The study area is located at 42 km NE of Qorveh city, in KordestanProvince and in the Metamorphic– Magmatic Sanandaj-Sirjan Zone. There are other important gold mines such as the Zarshouran and Aghdarreh mines in this zone. The most important alterations of the region are sericitic (phyllic), argillic, silicification and propylitic respectively. Therefore, in this research, the phyllic and argillic alterations were the main purpose and by using different techniques of images processing of satellite images such as: False Color Composition, Band Ratio, Principal Component analysis, Crosta and finally by Spectral Angle Mapper methods iron oxides and development of alterations have been recognized. For accuracy between field evidences and results of software processing, X-Ray Diffraction analysis were used for controlling and recognizing the index minerals of each zone. Then, the comparison between standard and the study area curves were done to confirm the obtaining results. Finally, this method was effective in recognizing and mapping of the hydrothermal alterations.
R Ahmadi Rohany; M.H Karimpour; B Rahimi; A Malakzadeh Shafaroudi
Abstract
The studied area is located in east of BajestanTownship, KhorasanRazaviProvince and this region is a part of the Lut Block. Granite is the most important rock in this area with covering approximately 70km2. Processing of satellite data in this area was done by using of SPOT, ASTER and Landsat ETM+ data. ...
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The studied area is located in east of BajestanTownship, KhorasanRazaviProvince and this region is a part of the Lut Block. Granite is the most important rock in this area with covering approximately 70km2. Processing of satellite data in this area was done by using of SPOT, ASTER and Landsat ETM+ data. SPOT images processing and using PCA methods (standard and selective) on the ETM+ data show this intrusive body doesn't have an equal chemical composition. The central part of the intrusive body has distinctive from margin and it seems that the central part have more mafic mineral. For enhancing linear structure, high pass, directional, threshold and sobel filters were applied separately and compositional on the SPOT data. By using these filters linear structures became completely obvious and were vectorized digitally. The most of them show northwestern-southeastern trend. ASTER data processing by spectral angle mapper (SAM), band ratio and band composition methods enhanced epidote, sericite, hematite, argilic and silicified alterations. Processing and Interpretation of airborne geophysical data (potassium, thorium, uranium and total magnetic intensity), which collected by airplane show the amounts of these triple elements (K,U,Th) are high and in vice versa Total Magnetic Intensity data (TMI) is low in this granite. Separating geological boundaries and enhancing major faults are other results from processing of geophysics data. Merging all of the data consist of: satellite and geophysics data processing and field research indicate alteration zones have relation to linear structures in this area. This research specifies the most probability of mineralization presence in this area so that Fe and Cu mineralization conform to epidotic-chloritic and argilic alterations. Introducing favorable area can help us to concentrate exploration activities and next researches in this area and prevent wasting money and time.
D Refahi; A Khakzad; N Nezafati; Kh Bahar Firozi; A Bayatani
Abstract
Development of advance tools in remote sensing and airborne geophysics during recent decades shows this industry importance. In this paper, aster sensor imagery (Advanced Space born Thermal – Radiometer) and airborne geophysics employed in order to zoning alteration area, mineralization system ...
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Development of advance tools in remote sensing and airborne geophysics during recent decades shows this industry importance. In this paper, aster sensor imagery (Advanced Space born Thermal – Radiometer) and airborne geophysics employed in order to zoning alteration area, mineralization system analysis and prospecting in 1:25000 Oghlansar sheet, which is situated in north of Sarab City in East Azerbaijan province. The area is located in structural zone of theEastern Alborz-Azerbaijan. The lithology of area contains Eocene-Neogene magmatic-volcanic complex such as andesite, rhyodacite, rhyolite, and granodiorite associated with pyroclastics such as tuffs, volcanic breccia and lava flows. In this investigation, we applied different methods of spectral analysis and normal classification such as SAM (Spectral Angel mapping), MF (Match Filtering) using ASTER images. Furthermore, spectral analysis methods on airborne geophysics data were engaged in order to extract shallow bodies and recognition of faults. ASTER imagery process and airborne geophysics data led to primary potential mineral map of the area. For credibility of results, 200 samples were taken and analyzed by XRD, XRF and ICP methods. Consequently, 190 samples (95%) confirmed the results of remote sensing and airborne geophysics processes. Conclusions of this research revealed that applying concurrency both the remote sensing and airborne geophysics data could be led to improve the precision of the results.
M. H. Tangestani; L. Jafari
Abstract
Various atmospheric correction algorithms were performed on ASTER L1B VNIR+SWIR datasets, and the results were compared with calibrated AST-07 dataset to introduce the best method. Neyriz ophiolite was chosen as a test area for this purpose. ASTER VNIR+SWIR datasets were calibrated to apparent reflectance ...
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Various atmospheric correction algorithms were performed on ASTER L1B VNIR+SWIR datasets, and the results were compared with calibrated AST-07 dataset to introduce the best method. Neyriz ophiolite was chosen as a test area for this purpose. ASTER VNIR+SWIR datasets were calibrated to apparent reflectance using two techniques: 1-Absolute atmospheric correction methods including ATCOR-2 (Atmospheric correction), ATCOR-3 (Atmospheric and Topographic correction); 2- Relative atmospheric correction methods that included IARR (Internal Average Relative Reflectance), FF(Flat Field), EL(Empirical Line), LR(Log Residuals), DOS(Dark Object Subtraction), AR (Apparent Reflectance) and COS(t). Results were evaluated by principal components analysis (Image-based algorithm) and spectral angle mapping (spectrum-based algorithm). Field spectra were used as end-members and confusion matrix was used for comparing the results of spectral angle mapping. Results of calibrated images showed that applied methods could be ranked in descending order according to the achieved accuracy of enhancing rock units as ATCOR-3, AST-07، IARR، LR, SWIR data set (L1B) and other methods had low accuracy for enhancing rock units.
Kh. Ebrahimi; p. Roohbakhsh; S. M. Homam; H. Abbasnia
Abstract
Dahaneh Qaleh exploration prospect is located about 300 km southwest of Mashhad and 50 km northwest of Bardeskan. The exploration prospect is also a part of Taknar massive sulfide mineralization zone and lithology of the area consists of chlorite sericite schist, biotite sericite schist and sericite ...
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Dahaneh Qaleh exploration prospect is located about 300 km southwest of Mashhad and 50 km northwest of Bardeskan. The exploration prospect is also a part of Taknar massive sulfide mineralization zone and lithology of the area consists of chlorite sericite schist, biotite sericite schist and sericite schist with metamorphosed basic and intermediate igneous rocks in the type range from meta-gabbro diorite to meta-diorite that they belong to Taknar Formation.Taknar Formation was intrusived by low grade metamorphosed intermediate subvolcanic intrusive rocks with porphyry texture in the type range of meta-hornblende-quartz monzonite porphyry, meta-hornblende-quartz monzodiorite porphyry, meta-hornblende monzodiorite porphyry, meta-quartz monzonite porphyry and meta-hornblende-quartz monzosyenite porphyry. All of the geological unites are affected by moderate to severe alteration and sulfide minerals including pyrite, were transformed to secondary iron oxides due to oxidation. Before the field investigation, ETM+ and ASTER sensors data were processed with "color composition of band ratios", "standard and selective principal component analysis" methods and finally "spectral angle mapping" as a successful method for more accurate separation of altered minerals that introduced Hematitic, Chloritic, Epidotic, Sericitic and Silicification alteration zones in the study area. Accuracy of the processes were proved by the following field, petrography and mineralography studies.
M. Abbaszadeh; Ardeshir Hezarkhani
Abstract
Rabor area is located in 160 km south of Kerman city and 40 km east of Baft. There is some evidence illustrating some porphyry copper type mineralization, co-operated with tens of within Urumieh-Dokhtar volcanic belt stocks. Identification of the high potential localities and mapping the porphyry copper ...
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Rabor area is located in 160 km south of Kerman city and 40 km east of Baft. There is some evidence illustrating some porphyry copper type mineralization, co-operated with tens of within Urumieh-Dokhtar volcanic belt stocks. Identification of the high potential localities and mapping the porphyry copper mineralization within these sites look very necessary. To aim for this goal, we aimed to identify the probable mineralization zones related porphyry copper mineralization alteration haloes in Rabor. In this research, by using the satellite image processing of ASTER sensor, applying the methods such as band ratioing, principal component analysis (PCA) and selective principal component analysis (Crosta) as well as the direct data from the Baft geological map (1:100000), available metallogenical theories and porphyry copper mineralization models, prepare images based on available clay mineral concentration maps from the region could provide evidences for an existence of a porphyry copper mineralization. Band ratioing was applied to discriminate the altered areas from the non-altered ones and also area lithology, porphyry copper deposit boundaries by identification of kaolinite, alunite and illite as indicator minerals within the studied area. Selective principal component analysis was also applied to produce the clay mineral concentration indicator maps to potential mining area recognition. Ore index cross matching called Pey Negin based recognition presumed area, demonstrates the selective principal component analysis method accuracy and its efficiency by using the satellite ASTER data from the altered area.
F. Masoumi; H. Ranjbar
Abstract
The study area covers the northern half of the Baft 1/100000 geological map in Dehaj-Sarduiyeh volcanic-sedimentary and ophiolitic belts. The aim of this research was application of multispectral ASTER and ETM+ data for determining the altered areas by using different image processing techniques. In ...
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The study area covers the northern half of the Baft 1/100000 geological map in Dehaj-Sarduiyeh volcanic-sedimentary and ophiolitic belts. The aim of this research was application of multispectral ASTER and ETM+ data for determining the altered areas by using different image processing techniques. In order to separate altered zones, false color composite of the ratios was applied on ASTER data that separated propylitic and phyllic/argillic altered zones. Separation of carbonate areas from the altered areas was achieved by making false color composite ratios. Another method for separation of carbonate areas from the altered zone was by applying principal component analysis (PCA) on short wave bands of ASTER data. A color composite of PC2, PC3, -PC4 in red, green and blue respectively was useful for separating carbonate from altered areas. Spectral Angle mapper method was also used for recognizing and mapping the minerals such as muscovite, chlorite, kaolinite, calcite and epidote in altered zones. Sampling from the altered areas and their analysis showed that this method could be used for recognizing the minerals in the altered areas, if they have enough spatial extent.
S. M. Masoudi; F. Fereidoni; & A. A. Matkan
Abstract
In this study, for the first time, Pumices around Damavand Mountain is studied by IRS-1C, Aster and ETM+ images. For this purpose at first, all images are preprocessed. It means geometric corrections and registering images together and with topography maps (1:25000) are done. Then atmospheric corrections, ...
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In this study, for the first time, Pumices around Damavand Mountain is studied by IRS-1C, Aster and ETM+ images. For this purpose at first, all images are preprocessed. It means geometric corrections and registering images together and with topography maps (1:25000) are done. Then atmospheric corrections, calibration of radiance and reflectance and topographic correction with Minneart method are done too. Preprocessing, some techniques like PCA, IHS, OIF, FCC and SAM have been done. Pan image of IRS-1C satellite for data fusion in visible and near infrared of Aster at visual interpretation and recognizing of roads and mines is better than ETM images. After data preprocessing, some techniques like PCA, IHS, OIF, FCC and SAM have been done. Pan image of IRS-1C satellite for data fusion in visible and near infrared of Aster at visual interpretation and recognizing of roads and mines is better than ETM images. IHS and PCA methods equally have separated clearly Pumice mines and trachyandesites without vegetations and soils covers. With respect to VNIR of Aster has more intensity than other spectral areas. Also because of high topographic changes and pampas vegetation, visible bands and Very Near Infrared (VNIR) of Aster aren't too useful. These spectral areas are caused mixing classes together, especially limestones and pumice. Totally for most of stones and different ores, spectral area of Short Wave Infrared (SWIR) of Aster has the best ability. For categorizing and extracting pumices potential layers from images, sampling is done on pixel or pixels that contain pumice mines. Because of less expansion of mines, samples are picked up on just one pixel or in maximum case ten pixels. According to that limitation, Spectral Angle Method (SAM) technique has more ability than the other methods. Use of DEM for separation flat or low dip lands whereas are placed for Pumices in northern, eastern and some southern parts of studied area is effective, but any worthwhile tracks of pumice weren’t found in south-west of mountain. Finally mining hopeful areas in cast of mining potential map is prepared. By calculating the overlay of effective geology structure layer with pumice mines areas layer, which is extracted from PAN image, the amount of overlay is calculated ninety three percent.
