scholarly journals Applying spectral analysis for identification of alteration zones in north Saveh area, Iran

2020 ◽  
Author(s):  
Kazem Rangzan ◽  
Somayeh Beyranvand ◽  
Hoshang Pourkaseb ◽  
Hojjatollah Ranjbar ◽  
Alireza Zarasvandi
Keyword(s):  
Hydrothermal Alteration ◽  
Near Infrared ◽  
Thermal Emission ◽  
Spectral Response ◽  
Volcanic Rocks ◽  
Short Wave ◽  
Rapid Identification ◽  
Spectral Angle Mapper ◽  
Alteration Zones ◽  
The North

An extensive series of volcanic rocks are exposed in the north of Saveh city, Iran, which consist of phyllic, argillic and propylitic hydrothermal alteration types. For the purpose of the investigation, a FieldSpec3® spectroradiometer was used to measure the spectral response of the mineral content of these rocks. The spectral analyses of reflectance curve by The Spectral Geologist (TSG) software could discriminate kaolinite and montmorillonite (argillic), illite, muscovite, phengite and paragonite (phyllic), hornblende and chlorite, siderite (propylitic), hematite and goethite from the gossans. It also detected gypsum of hydrothermal alteration zones. The Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) image, which was used for mapping the hydrothermal alteration minerals, contains the Visible and Near Infrared (VNIR) wavelengths between 0.52 µm and 0.86 µm, Short Wave Infrared (SWIR) wavelengths between 1.6 µm and 2.43 µm and Thermal Infrared (TIR) wavelengths between 8.125 µm and 11.65 µm with 15, 30 and 90 m spatial resolutions, respectively. For calibration of the ASTER images, the extracted spectra of different rocks and minerals were used for atmospheric and radiometric corrections. Mixture tuned matched filtering (MTMF) and Spectral Angle Mapper (SAM) were applied on ASTER data to map the hydrothermal alteration of minerals. The use of the spectroradiometry techniques in conjunction with other data exhibits the ability of these new methods for non-destructive and rapid identification of mineral types for more detailed investigation. The results show that the area has undergone different levels of hydrothermal alteration, so much so that phyllic, argillic and propylitic types of hydrothermal alteration are present in the study area. This may point to high potential and promising zones for the exploration of porphyry mineralisation.

scholarly journals Lithological mapping of East Tianshan area using integrated data fused by Chinese GF-1 PAN and ASTER multi-spectral data

2018 ◽  
Vol 10 (1) ◽  
pp. 532-543 ◽  
Author(s):  
Min Yang ◽  
Lei Kang ◽  
Huaqing Chen ◽  
Min Zhou ◽  
Jianghua Zhang
Keyword(s):  
Spectral Resolution ◽  
Near Infrared ◽  
Thermal Emission ◽  
Low Cost ◽  
Short Wave ◽  
Support Vector ◽  
Tianshan Mountain ◽  
Multispectral Data ◽  
Fusion Data ◽  
East Tianshan

Abstract The East Tianshan Mountain is one of the most important gold ore forming zones in northwestern China and central Asia. The Chinese GaoFen-1 (GF-1), the first Chinese high resolution satellite, is characterized by its 2-m resolution PAN data. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the well-known earth observation satellite, is advanced by its finer spectral resolution owing 9 bands in the visible and near infrared (VNIR) to the short-wave infrared (SWIR) region. In this study, we fused the GF-1 PAN and the ASTER multispectral data using the well-known Gram-Schmidt Pan Sharpening (G-S) method to produce a new data with both high spatial and spectral resolution. Then different lithological units were mapped respectively using the fusion data, the ASTER data and the WorldView-3 data by support vector machine (SVM) method. In order to assess this fusion data, a comparison work was executed among the three mapping results. The comparison work indicated that lithological classification using the new fusion data is an efficient, robust and low cost method, and it could replace the WV-3 data in some large sale geological work.

Acid-sulphate hydrothermal alteration of andesitic tuffs and genesis of halloysite and alunite deposits in the Biga Peninsula, Turkey

Clay Minerals ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 281-315 ◽  
Author(s):  
Ö. I. Ece ◽  
P. A. Schroeder ◽  
M. J. Smilley ◽  
J. M. Wampler
Keyword(s):  
Hydrothermal Alteration ◽  
Volcanic Rocks ◽  
Geothermal Field ◽  
Parent Material ◽  
Thermal Waters ◽  
Geothermal Waters ◽  
Biga Peninsula ◽  
The North ◽  
Clay Deposits ◽  
Nw Turkey

AbstractThe Biga Peninsula of NW Turkey is host to six major halloysite deposits in the Go¨nen, Yenice and Balya districts. Mineralization took place in areas of Permian limestone blocks where the Triassic Karakaya Complex is in contact with early Miocene calc-alkaline volcanic rocks. Hypogene halloysite mineralization was controlled by the intersection of minor faults in the vicinity of clay deposits. During the Pleistocene, activity of the North Anatolian Fault (NAF) brought ascending geothermal solutions through the fault zones to the surface, which led to hydrothermal alteration and halloysite formation. N-MORB normalized element values for each halloysite deposit and the volcanic rocks suggest genetic links. Alunite and halloysite were formed in the Turplu area where upwelling hydrothermal waters contained major H2S and SO2acids. Only halloysite mineralization occurred in outflow areas of the same fossil geothermal field.Pyrite and alunite samples from the Turplu deposits have δ34S values of 0.6–1.8% and 4.8–7.9%, respectively, with values for gypsum of 3.1–3.5%. The δ34S values of pyrite suggest that local meteoric waters had partially mixed with the dominant fluid during the closure stage of fossil hydrothermal activities. The range of δD values of halloysite samples from Turplu is –58.4 to –68.6%. The δ18O values for halloysite are in the range 16.7–18.1%. All halloysite deposits in the study areas are either overlying or adjacent to limestone blocks, and these provide excellent drainage for the discharging geothermal waters. Subsurface drainage systems in the karstic environment and the SO2-bearing thermal waters indicate the importance of acidic waters and the continuous leaching of elements in forming relatively pure hydrated halloysite. A steam-heated dissolution-precipitation model is proposed for the occurrence of all halloysite and alunite deposits. Sulphur gases (H2S-SO2) of hypogene origin rose from deep in the fault zone to the surface where they encountered oxygenated groundwater at the water table. The occurrence of H2SO4in this hydrothermal system enhanced the acidity of geothermal waters provoking advanced argillic alteration. Hypogene alunite deposits also have large P2O5contents, suggesting a parent material with a magmatic origin deeper than the alkaline tuffs. Halloysite is a fast-forming metastable precursor to kaolinite.

scholarly journals Hybrid Fuzzy-Analytic Hierarchy Process (AHP) Model for Porphyry Copper Prospecting in Simorgh Area, Eastern Lut Block of Iran

Mining ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
Vahid Khosravi ◽  
Aref Shirazi ◽  
Adel Shirazy ◽  
Ardeshir Hezarkhani ◽  
Amin Beiranvand Pour
Keyword(s):  
Hydrothermal Alteration ◽  
Thermal Emission ◽  
Fuzzy Ahp ◽  
Porphyry Copper ◽  
High Potential ◽  
Ahp Model ◽  
Alteration Zones ◽  
Copper Mineralization ◽  
Lut Block ◽  
Hydrothermal Alteration Zones

The eastern Lut block of Iran has a high potential for porphyry copper mineralization due to the subduction tectonic regime. It is located in an inaccessible region and has harsh arid conditions for traditional mineral exploration campaigns. The objective of this study is to use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing data for porphyry copper exploration in Simorgh Area, eastern Lut block of Iran. Hydrothermal alteration zones such as argillic, phyllic and propylitic zones associated with porphyry copper systems in the study were identified using false color composition (FCC), band ratio (BR), principal component analysis (PCA) and minimal noise fraction (MNF). The thematic alteration layers extracted from FCC, BR, PCA and MNF were integrated using hybrid Fuzzy-AHP model to generate a porphyry copper potential map for the study area. Four high potential zones were identified in the central, western, eastern and northeastern of the study area. Fieldwork was used to validate the approach used in this study. This investigation exhibits that the use of hybrid Fuzzy-AHP model for the identification of hydrothermal alteration zones associated with porphyry copper systems that is typically applicable to ASTER data and can be used for porphyry copper potential mapping in many analogous metallogenic provinces.

SPECTRAL RESPONSE MEASUREMENTS OF SHORT WAVE INFRARED DETECTORS (SWIR)

2002 ◽  
Vol 12 (02) ◽  
pp. 541-550 ◽  
Author(s):  
TAMER F. REFAAT ◽  
M. NURUL ABEDIN ◽  
UPENDRA N. SINGH
Keyword(s):  
Bias Voltage ◽  
Infrared Detectors ◽  
Near Infrared ◽  
Spectral Response ◽  
Short Wave ◽  
Electrical Signal ◽  
External Bias ◽  
Short Wave Infrared ◽  
Critical Components ◽  
Processing And Storage

Quantum detectors are critical components in infrared lidar receivers. They convert the optical return signal into electrical signal compatible with electronic data processing and storage devices. The detectors used in this study comprise InGaAs PIN diodes and InGaAsSb avalanche photodiodes (APDs) for short wave infrared applications and Si APDs, with different structures, for near-infrared applications. The spectral response of these infrared detectors utilized for lidar receivers was studied with respect to operating temperature and external bias voltage. Variation of these spectral responses as a function of bias voltage and temperature was determined. This variation is employed to estimate errors in the detected lidar return signal. Results of this research finding are reported in this article.

scholarly journals New method to determine the instrument spectral response function, applied to TROPOMI-SWIR

2017 ◽  
Author(s):  
Richard M. van Hees ◽  
Paul J. J. Tol ◽  
Sidney Cadot ◽  
Matthijs Krijger ◽  
Stefan T. Persijn ◽  
...  
Keyword(s):  
Response Function ◽  
Near Infrared ◽  
Spectral Response ◽  
Short Wave ◽  
Trace Gas ◽  
Imaging Spectrometer ◽  
Swir Band ◽  
Novel Method ◽  
Single Instrument

Abstract. The Tropospheric Monitoring Instrument (TROPOMI) is the single instrument on board of the ESA Copernicus Sentinel-5 Precursor satellite. TROPOMI is a nadir-viewing imaging spectrometer with bands in the ultraviolet and visible, the near infrared and the short-wave infrared (SWIR). An accurate instrument spectral response function (ISRF) is required in the SWIR band where absorption lines of CO, methane and water vapor overlap. Therefore a novel method for ISRF determination for an imaging spectrometer was developed and applied to the TROPOMI-SWIR band. The ISRF of all detector pixels of the SWIR spectrometer has been measured during an on-ground calibration campaign. The accuracy of the derived ISRF is well within the requirement for accurate trace-gas retrievals. Long-term in-flight monitoring of the ISRF is guaranteed by the presence of five SWIR diode lasers.

scholarly journals Lithological mapping and automatic lineament extraction using Aster and Gdem data in the Imini-Ounilla-Asfalou district, South High Atlas of Marrakech, Morocco

2021 ◽  
Vol 240 ◽  
pp. 04002
Author(s):  
Abdelouhed Farah ◽  
Ahmed Algouti ◽  
Abdellah Algouti ◽  
Kamal El badaoui ◽  
Maryam Errami ◽  
...  
Keyword(s):  
Near Infrared ◽  
Satellite Image ◽  
Principal Component ◽  
Short Wave ◽  
Spectral Angle Mapper ◽  
High Atlas ◽  
Lithological Mapping ◽  
High Concentrations ◽  
Lineament Extraction ◽  
Automatic Lineament Extraction

Lithological and lineament mapping using remote sensing is a fundamental step in various geological studies, as it forms the basis for the interpretation and validation of the results obtained. There were two objectives for this study, applied in the Imini-Ounilla-Asfalou district, South High Atlas of Marrakech region: first, lithological mapping by satellite image processing techniques such as ASTER L1B (hight spectral and spatial resolution), namely Principal Component Analysis (PCA), Minimum Noise Fraction (MNF), as well as the application of three types of supervised classification, namely Spectral Angle Mapper (SAM), Maximum Likelihood (ML) and Minimum Distance (MD), on the visible/near-infrared (VNIR) and short-wave infrared (SWIR) spectral bands of our ASTER image; second, an analysis of the distribution of lineaments by automatic extraction using a Global Digital Elevation Model (GDEM) and the PC1 image derived from the PCA transformation applied to the satellite image. The best results are highlighted by the delineation of new facies in relation to the existing map; after confirmation in the field, all of these facies, which include Eocene, Triassic and Jurassic formations, are represented on the new map. The results of lineaments showed that each of them systematically shows a similarity in terms of concentration and orientation, with four preferential oriented systems: NE-SW, E-W, NNE-SSW and NW-SE. The lineaments mainly follow those of the major fault zones, with high concentrations in the northeast and southwest parts of the study area.

scholarly journals Identification of Phyllosilicates in the Antarctic Environment Using ASTER Satellite Data: Case Study from the Mesa Range, Campbell and Priestley Glaciers, Northern Victoria Land

2020 ◽  
Vol 13 (1) ◽  
pp. 38
Author(s):  
Amin Beiranvand Pour ◽  
Milad Sekandari ◽  
Omeid Rahmani ◽  
Laura Crispini ◽  
Andreas Läufer ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Near Infrared ◽  
Thermal Emission ◽  
Ground Truth ◽  
Xrd Analysis ◽  
Short Wave ◽  
Metamorphic Complex ◽  
Victoria Land ◽  
The Antarctic ◽  
Antarctic Environment

In Antarctica, spectral mapping of altered minerals is very challenging due to the remoteness and inaccessibility of poorly exposed outcrops. This investigation evaluates the capability of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite remote sensing imagery for mapping and discrimination of phyllosilicate mineral groups in the Antarctic environment of northern Victoria Land. The Mixture-Tuned Matched-Filtering (MTMF) and Constrained Energy Minimization (CEM) algorithms were used to detect the sub-pixel abundance of Al-rich, Fe3+-rich, Fe2+-rich and Mg-rich phyllosilicates using the visible and near-infrared (VNIR), short-wave infrared (SWIR) and thermal-infrared (TIR) bands of ASTER. Results indicate that Al-rich phyllosilicates are strongly detected in the exposed outcrops of the Granite Harbour granitoids, Wilson Metamorphic Complex and the Beacon Supergroup. The presence of the smectite mineral group derived from the Jurassic basaltic rocks (Ferrar Dolerite and Kirkpatrick Basalts) by weathering and decomposition processes implicates Fe3+-rich and Fe2+-rich phyllosilicates. Biotite (Fe2+-rich phyllosilicate) is detected associated with the Granite Harbour granitoids, Wilson Metamorphic Complex and Melbourne Volcanics. Mg-rich phyllosilicates are mostly mapped in the scree, glacial drift, moraine and crevasse fields derived from weathering and decomposition of the Kirkpatrick Basalt and Ferrar Dolerite. Chlorite (Mg-rich phyllosilicate) was generally mapped in the exposures of Granite Harbour granodiorite and granite and partially identified in the Ferrar Dolerite, the Kirkpatrick Basalt, the Priestley Formation and Priestley Schist and the scree, glacial drift and moraine. Statistical results indicate that Al-rich phyllosilicates class pixels are strongly discriminated, while the pixels attributed to Fe3+-rich class, Fe2+-rich and Mg-rich phyllosilicates classes contain some spectral mixing due to their subtle spectral differences in the VNIR+SWIR bands of ASTER. Results derived from TIR bands of ASTER show that a high level of confusion is associated with mafic phyllosilicates pixels (Fe3+-rich, Fe2+-rich and Mg-rich classes), whereas felsic phyllosilicates (Al-rich class) pixels are well mapped. Ground truth with detailed geological data, petrographic study and X-ray diffraction (XRD) analysis verified the remote sensing results. Consequently, ASTER image-map of phyllosilicate minerals is generated for the Mesa Range, Campbell and Priestley Glaciers, northern Victoria Land of Antarctica.

scholarly journals The operational methane retrieval algorithm for TROPOMI

2016 ◽  
Author(s):  
Haili Hu ◽  
Otto Hasekamp ◽  
André Butz ◽  
André Galli ◽  
Jochen Landgraf ◽  
...  
Keyword(s):  
Response Function ◽  
Near Infrared ◽  
Spectral Response ◽  
Short Wave ◽  
Retrieval Algorithm ◽  
Model Errors ◽  
Instrument Calibration ◽  
Atmospheric Scattering ◽  
Accuracy And Precision ◽  
Land Surfaces

Abstract. This work presents the operational methane retrieval algorithm for the Sentinel-5 Precursor (S5-P) satellite and its performance tested on realistic ensembles of simulated measurements. The target product is the column-averaged dry air volume mixing ratio of methane (XCH4), which will be retrieved simultaneously with scattering properties of the atmosphere. The algorithm attempts to fit spectra observed by the shortwave and near-infrared channels of the TROPOMI spectrometer aboard S5-P. The sensitivity of the retrieval performance to atmospheric scattering properties, atmospheric input data and instrument calibration errors is evaluated. Also, we investigate the effect of inhomogeneous slit illumination on the instrument spectral response function. Finally, we discuss the cloud filters to be used operationally and as backup. We show that the required accuracy and precision of < 1 % for the XCH4 product are met for clear sky measurements over land surfaces and after appropriate filtering of difficult scenes. The algorithm is very stable having a convergence rate of 99 %. The forward model error is less than 1 % for about 95 % of the valid retrievals. Model errors in the input profile of water do not influence the retrieval outcome noticeably. The methane product is expected to meet the requirements if errors in input profiles of pressure and temperature remain below 0.3 % and 2 K, respectively. We find further that, of all instrument calibration errors investigated here, our retrievals are the most sensitive to an error in the instrument spectral response function of the short-wave infrared channel.

scholarly journals Recognition of Minerals Using Multispectral Remote Sensing Data: A Case Study in the Sultanate of Oman

2015 ◽  
Vol 19 (2) ◽  
pp. 37 ◽  
Author(s):  
Sankaran Rajendran ◽  
Sobhi Nasir
Keyword(s):  
Near Infrared ◽  
Thermal Emission ◽  
Image Interpretation ◽  
Remote Sensing Data ◽  
Source Rocks ◽  
Sultanate Of Oman ◽  
Alluvial Deposits ◽  
Study Region ◽  
Spectral Angle Mapper ◽  
Rock Types

The present study demonstrates the capability of a multispectral sensor for the detection of the minerals in the rocks surrounding the Rusayl and Al Jafnayn regions, Sultanate of Oman. The study of spectral absorptions of rocks and minerals in the visible and near infrared (VNIR) and short wavelength infrared (SWIR) spectral bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) using the Spectral Angle Mapper (SAM) supervised image classification technique has provided information on the occurrence of minerals in the rock types of the regions. The study shows the occurrence of carbonate minerals in the limestone formations and of poorly altered silicate minerals in the basic dyke rocks of the study regions. The analysis of minerals over the ancient terraces and recent alluvial deposits show that the deposit materials are derived from the dykes and foliated gabbro source rocks. The image interpretation is compared to the geological map, verified in the field and confirmed through laboratory analyses. The satellite data and the image processing techniques used have potential in the recognition of minerals in the rocks of the study region and could be used in similar arid regions elsewhere in the world.  

Sign in / Sign up

Export Citation Format

Share Document