PRELIMINARY DETECTION OF GEOTHERMAL MANIFESTATION POTENTIAL USING MICROWAVE SATELLITE REMOTE SENSING

The satellite technology has developed significantly. The sensors of remote sensing satellites are in the form of optical, Microwave, and LIDAR. These sensors can be used for energy and mineral resources applications. The example of those applications are height model and the potential of geothermal manifestation detection. This study aims to detect the potential of geothermal manifestation using remote sensing. The study area is the Northern of the Inverse Arc of Sulawesi. The method used is remote sensing approach for its preliminary detection with 4 steps as follow (a) mining land identification, (b) geological parameter extraction, (c) preparation of standardized spatial data, and (d) geothermal manifestation. Mining lands identification is using Vegetation Index Differencing method. Geological parameters include structural geology, height model, and gravity model. The integration method is used for height model. The height model integration use ALOS PALSAR data, Icesat/GLAS, SRTM, and X SAR. Structural geology use dip and strike method. Gravity model use physical geodesy approach. Preparation of standardized spatial data with re-classed and analyzed using Geographic Information System between each geological parameter, whereas physical geodesy methods are used for geothermal manifestation detection. Geothermal manifestation using physical geodesy approach in Barthelmes method. Grace and GOCE data are used for gravity model. The geothermal manifestation detected from any parameter is analyzed by using geographic information system method. The result of this study is 10 area of geothermal manifestation potential. The accuracy test of this research is 87.5 % in 1.96 σ. This research can be done efficiently and cost-effectively in the process. The results can be used for various geological and mining applications

PENGINDERAAN JAUH UNTUK PENDETEKSIAN AWAL POTENSI TEMBAGA DI SUMBAWA

Tembaga merupakan salah satu jenis mineral penting yang memiliki banyak fungsi dalam berbagai aplikasi. Penelitian ini bertujuan untuk pendeteksian awal tembaga menggunakan data penginderaan jauh. Lokasi penelitian terletak di Sumbawa. Data penginderaan jauh yang digunakan berupa Landsat, ALOS Palsar, X SAR, SRTM C, dan Satelit Geodesi. Landsat digunakan untuk ekstraksi parameter geologi berupa penutup lahan dan perubahannya, bentuk lahan, dan alterasi hidrotermal. ALOS PALSAR, X SAR, dan SRTM C digunakan untuk pembuatan DTM (Digital Terrain Model). Integrasi DTM berguna untuk ekstraksi parameter geologi lainnya berupa struktur dan formasi geologi. DTM yang digunakan memiliki akurasi vertikal + 1,5 m. Data Satelit Geodesi bisa digunakan untuk ekstraksi gaya berat, medan magnet, geodinamika, serta densitas batuan. Berbagai parameter geologi ini diekstraksi dengan metode VIDN, integrasi, dip and strike, interferometri, backscattering, alterasi hidrotermal, geodesi fisis, dan klasifikasi digital berbasis objek. Semua parameter geologi yang telah diekstrak dikorelasikan antar data, sehingga bisa digunakan untuk deteksi potensi tembaga. Informasi geospasial deteksi awal tembaga dan ekstraksi parameter geologinya merupakan produk yang dihasilkan dari penelitian ini. Informasi geospasial ini menggunakan referensi ketelitian ASPRS Accuracy Data for Digital Geospatial Data.Copper is one of the essential mineral that has many functions in variety of applications. This research aimed to detect the copper potential using remote sensing data. The research location is Sumbawa. Remote sensing data used were Landsat, ALOS PALSAR, X SAR, SRTM C, and Satellite Geodesy. Landsat was used for geological parameters extraction such as land cover and its changes, geomorphology, landforms, and hydrothermal alteration. ALOS PALSAR, X SAR and SRTM C were used for height model integration (DTM). This DTM was useful for the other geological parameters extraction, such as geological structures and formations. DTM used has vertical accuracy + 1,5 m. Geodesy Satellite data can be used for the extraction of gravity, magnetic field, geodynamics, and rock densities. These various geological parameters were extracted by VIDN, integration, dip and strike, interferometry, backscattering, hydrothermal alteration, physical geodesy, and classification based digital objects. All of those parameters were then correlated for copper potential detection. The results obtained were geospatial information of copper potential and geological parameters at a scale of 1: 50.000 with reference ASPRS Accuracy Data for Digital Geospatial Data.

Detecting Oxides Mineralization Utilizing Remote Sensing and Comprehensive Mineralogical Analysis: A Case Study Around Mikbi-Zayatit District, South Eastern Desert, Egypt

Undoubtedly, involving more tools, datasets, and techniques for detecting the mineralized areas sharply narrow the zones to be investigated and delivered, in most cases highly potential zones. Consequently, this study is an attempt to apply remote sensing data including Sentinel 2 and ASTER, field observations, petrography of the hydrothermal alteration processes, ore microscopic investigations, X-ray examinations, and EDX analysis to detect and emphasize mineralization types at Wadi Mikbi and Wadi Zayatit district, South Eastern Desert, Egypt. Towards accurate lithological mapping, remote sensing data, previous geological maps, and the field investigations recorded serpentinites, ophiolitic metagabbros, amphibolites, epidosite, arc-related metasediments (schists and quartzites), metagabbro-tonalite complex, dunite, olivine gabbros, and granitic rocks encountered in the study district. Additionally, various hydrothermal alteration zones have been primarily outlined using ASTER and Sentinel 2 data by implementing informative band ratios and constrained energy minimization techniques. The mineralogical studies have confirmed most of the remotely-detected hydrothermal alteration minerals. Ore microscopy, XRD technique, and EDX microchemical analysis of representative mineralized samples of the study district identified magnetite, ilmenite, titanomagnetite, chromite, magnesioferrite, quartz, apatite, clinochlore, plagioclase, pyroxene and epidote. Cross-linking remote sensing results, field observations and laboratory studies revealed that the dominant hydrothermal alteration processes include oxidization, serpentinization, carbonatization, epidotization, silicification, zoisitization, muscovitization, sericitization, and chloritization. Spatial overlay analysis of the resultant altered features, structural dissection, field observations, and analytical studies were integrated to build a mineral potentiality map of the study district

Towards better delineation of hydrothermal alterations via multi-sensor remote sensing and airborne geophysical data

Integrating various tools in targeting mineral deposits increases the chance of adequate detection and characterization of mineralization zones. Selecting a convenient dataset is a key for a precise geological and hydrothermal alteration mapping. Remote sensing and airborne geophysical data have proven their efficiency as tools for reliable mineral exploration. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced land imager (ALI), Landsat 8 (L8), and Sentinel 2 data are widely-used data among various types of remote sensing images in resolving lithological and hydrothermal alteration mapping over the last two decades. ASTER is a well-established satellite in geological remote sensing with detailed Short-wave infrared (SWIR) range compared to visible and near-infrared region (VNIR) that controls iron-associated alteration detection. On contrary, ALI has excellent coverage of the VNIR area (6 bands), but does not possess the potentiality of ASTER for the SWIR and thermal regions. Landsat 8 is widely used and highly recommended for lithological and hydrothermal alteration mapping. The higher spatial (up to 10 m) resolution of Sentinel 2 MSI has preserved its role in producing accurate geological mapping. Notwithstanding the foregoing, implementing the four datasets in a single study is time-consuming. Thus, an important question when commencing an exploration project for hydrothermal alterations-related mineralization (orogenic mineral deposits in the current research) is: which dataset should be adopted to fulfill proper and adequate outputs? Here the four widely recommended datasets (ASTER, ALI, L8, and sentinel 2) have been tested by applying the widely-accepted techniques (false color combinations, band ratios, directed principal component analysis, and constrained energy minimization) for geological and hydrothermal alteration mapping of Gabal El Rukham-Gabal Mueilha district, Egypt. The study area is covered mainly by Neoproterozoic heterogeneous collection of ophiolitic components, island arc assemblage, intruded by enormous granitic rocks. Additionally, airborne magnetic and radiometric data were applied and compared with the remote sensing investigations for deciphering the structural and hydrothermal alteration patterns within the study area. The results demonstrated a different extent from one sensor to another, highlighting their varied efficacy in detecting hydrothermal alterations (mainly hydroxyl-bearing alterations and iron oxides). Moreover, the analysis of airborne magnetic and radiometric data showed hydrothermal alteration zones that are consistent with the detected alteration pattern. The coincidence between high magnetic anomalies, high values of the K/eTh ratio, and the resultant alterations confirm the real alteration anomalies. Over and above that, the remote sensing results and airborne geophysical indications were verified with fieldwork and petrographic investigations, and strongly recommend combining ASTER and Sentinel 2 results in further investigations. Based on the outputs of the current research, we expect better hydrothermal alteration delineation by adopting the current findings as they sharply narrow the zones to be further investigated via costly geophysical and geochemical methods in mineral exploration projects

Targeting Mineral Resources with Remote Sensing and Field Data in the Xiemisitai Area, West Junggar, Xinjiang, China

The Xiemisitai area, West Junggar, Xinjiang, China, is situated at a potential copper mineralization zone in association with small granitic intrusions. In order to identify the alteration zones and mineralization characteristics of the intrusions, Landsat Enhanced Thematic Mapper (ETM+) and Quickbird data of the study area were evaluated in mapping lithological units, small intrusions, and alteration zones. False color composites of the first principal component analyses (PCA1), PCA2, and PCA4 in red (R), green (G), and blue (B) of the ETM+ image, and relevant hue-saturation-intensity (HSI) color model transformations, were performed. This led to the identification of lithologic units and discrimination of granitic intrusions from wall-rocks. A new geological map was generated by integrating the remote sensing results with two internally published local geologic maps and field inspection data. For the selected region, false color composites from PCA and relevant HSI-transformed images of the Quickbird data delineated the details of small intrusions and identified other unknown similar intrusions nearby. Fifteen separate potash-feldspar granites and three separate hornblende biotite granites were identified using ETM+ and Quickbird data. The principal component analysis-based Crosta technique was employed to discriminate alteration minerals. Some of the mapped alteration zones using the Crosta technique agreed very well with the known copper deposits. Field verification led to the discovery of three copper mineralizations and two gold mineralizations for the first time. The results show that the PCA and HSI transformation techniques proved to be robust in processing remote sensing data with moderate to high spatial resolutions. It is concluded that the utilized methods are useful for mapping lithology and the targeting of small intrusion-type mineral resources within the sparsely vegetated regions of Northwest China

Targeting Mineral Resources with Remote Sensing and Field Data in the Xiemisitai Area, West Junggar, Xinjiang, China

The Xiemisitai area, West Junggar, Xinjiang, China, is situated at a potential copper mineralization zone in association with small granitic intrusions. In order to identify the alteration zones and mineralization characteristics of the intrusions, Landsat Enhanced Thematic Mapper (ETM+) and Quickbird data of the study area were evaluated in mapping lithological units, small intrusions, and alteration zones. False color composites of the first principal component analyses (PCA1), PCA2, and PCA4 in red (R), green (G), and blue (B) of the ETM+ image, and relevant hue-saturation-intensity (HSI) color model transformations, were performed. This led to the identification of lithologic units and discrimination of granitic intrusions from wall-rocks. A new geological map was generated by integrating the remote sensing results with two internally published local geologic maps and field inspection data. For the selected region, false color composites from PCA and relevant HSI-transformed images of the Quickbird data delineated the details of small intrusions and identified other unknown similar intrusions nearby. Fifteen separate potash-feldspar granites and three separate hornblende biotite granites were identified using ETM+ and Quickbird data. The principal component analysis-based Crosta technique was employed to discriminate alteration minerals. Some of the mapped alteration zones using the Crosta technique agreed very well with the known copper deposits. Field verification led to the discovery of three copper mineralizations and two gold mineralizations for the first time. The results show that the PCA and HSI transformation techniques proved to be robust in processing remote sensing data with moderate to high spatial resolutions. It is concluded that the utilized methods are useful for mapping lithology and the targeting of small intrusion-type mineral resources within the sparsely vegetated regions of Northwest China