Remote Sensing Techniques for Geological Mapping with special reference to ornamental stones. N.S.Gadagkar Director

Transcription

1 Remote Sensing Techniques for Geological Mapping with special reference to ornamental stones N.S.Gadagkar Director Remote Sensing and Aerial Surveys GSI, Bengaluru Contents of presentation I Remote sensing concepts-data products II Elements of Image Interpretation and III Image analysis for geological mapping VI Newer technologies in Image analysis and interpretation 1

2 ELECTRO MAGNETIC SPECTRUM OPTICAL REMOTE SENSING THERMAL REMOTE SENSING MICROWAVE REMOTE SENSING : LISS PAN,LANDSAT,ASTER : LS-TM-TIR,ASTER : SAR, SLAR GEOLOGICALLY SIGNIFICANT REGIONS OF THE ELECTROMAGNETIC SPECTRUM Wavelength region Wavelength (nm) range VNIR SWIR Mineralogy Fe and Mn oxides, rare earths Hydroxyls, carbonates, sulphates, micas, amphiboles Associated molecular feature Crystal field absorption, charge transfer absorption Al(OH) 2, Fe(OH) 2, Mg(OH) 2, NH 4, SO 4 absorption, CO 3 TIR Carbonates, silicates Si-O bond distortion 2

3 Satellite Data products used in GSI IRS-IC RESOURCESAT LISS III 23.5m Spatial resolution Freely downloadable from Bhuvan Portal of NRSC CartoDEM for DEM applications IRS-IC RESOURCESAT LISS IV 5.8M Spatial Reoluation LANDSAT 7 ETM + (8 band data) from USGS/Glovis with 30m Resolution LANDSAT 8 OLI (11 band data) from USGS/H/Glovis with 30m resolution ASTER (14 band data) of Japan Space System purchased through NRSC 15/30M resolution ELEMENTS OF PHOTO/ IMAGE INTERPRETATION Tone Colour True Colour and False colour Texture Pattern. 1Drainage 2.Erosional 3.Vegetation 4.Outcrop Shape Size Association Landform & Landuse 3

4 Image Resolution The 4 R s of remote sensing imagery 1. Spatial Resolution 2. Radiometric Resolution 3. Spectral Resolution 4. Temporal Resolution 1. Spatial Resolution refers to the size of the smallest possible feature that can be sensed IRS 1C/D 5.8m (PAN) IKONOS 1m (PAN) RESOURCESAT 5.8m (xs) 4

5 2. Radiometric Resolution The number of brightness levels which the sensor can record The finer the radiometric resolution of a sensor, the more sensitive it is to detect small differences in reflected or emitted energy Spectral Resolution 5

6 Piecewise linear stretch Gaussian stretch Histogram equalization 6

7 True colour Image of part of Cuddapah basin Spectrally enhanced image 7

8 Decorrelated stretch Lithological mapping from TM Imagery Part of Chitradurga Schist Belt. 8

9 Lithological mapping from IRS Imagery Part of Ramagiri Schist Belt and surrounding area IRS-LISS-III FCC SE of Nagpur CHIMUR TADOBA-ANDHERI TIGER RESERVE NAWARGAON 9

10 IRS-LISS-III FCC SE of Nagpur for sheet 55P/6 &10 Gneisses Pengangas Gondwanas Lineament Fabric in part of Chandrapur dist, Maharashtra 55P/6 &10 10

11 IRS-L3-FCC of part of SAUSARS Maharashtra DEM IMAGE FROM SRTM DATA OVERLAID WITH TOPOSHEET & GEOLOGICAL MAP OF PART OF SAUSAR BELT /TBG FOR SHEET 55O/2,3,10&11 Mugnapal Sonpur Chandakpur Bhandetal Surewani Saleghat Dhavalpur 11

12 Nagpur-Wardha area Maharashtra Landsat ETM RGB = 432 Landsat ETM RGB = 532 Deccan Traps 27 Granite outcrop with convex slope 12

13 Exfoliation in Syenite Granites with vertical joints 13

14 Dongargarh Granite, Amgaon, Gondia Dist Dongargarh Granite near Amgaon,Gondia 14

15 Deccan basaltic flows near Pune Andesite flow 15

16 Pitepani Andesites near Duggipar,Gondia,Maharashta Typical Schist Belt Topography 16

17 Schistose rock exposure Surface level phyllite rocks 17

18 NATIONAL GEOMORPHOLOGICAL AND LINEAMENT MAPPING (NGLM) ON 1:50,000 SCALE USING SATELLITE DATA GSI-ISRO Collaborative Project National Geomorphological and Lineament mapping (NGLM) All India state level mosaicked NGLM geodatabase covering 4913 sheets completed (excluding 199 sheets in J&K) during Online Map Service developed by Geodata Division, CHQ in GSI Portal for viewing and querying geodatabase of NGLM. ( 18

19 GEOMORPHOLOGICAL AND LINEAMENT MAP Geomorphological and lineament map for Wardha area, 55L 19

20 Geomorphlogical and Lineament Map for parts of Chitradurga Schist belt- 57B Newer Technologies in use ASTER for Shortwave and Thermal Infrared windows for geological mapping Hyperspectral Imaging 20

21 Band Ratioed Outputs for identifying mineral clusters ETM+ Band 5/4 ratioed image showing Iron oxide concentration in parts of Sakolis sheets 55P/5& Iron oxide concentration Note the occurrence on land surface

22 ETM+ Band ratioed 5/7 image showing clay mineral concentration in sheets 55P/5& Clay mineral concentration in alluvium Clay and Iron oxide cluster zones in Sakolis from Band ratioed ETM+ data

23 Hyperspectral Remote Sensing What is it? The science of acquiring digital imagery of earth materials in many narrow contiguous spectral bands. Also referred to as imaging spectrometry. Differs from conventional remote sensing in that it covers many narrowly defined spectral channels, where as, conventional remote sensing looks at several broadly defined spectral regions. CONCEPTS 23

24 Hyperspectral sensors AIRBORNE HYPERSPECTRAL AVIRIS NASA TO 2.5 ( 10 NM, 20M SP,12 KM SWATH SNR 500:1) HYDICE NAVAL RESEARCH LAB TO 2.5 DIAS GERMAN 79 VISBLE TIR HYMAP ITRES RESEACH LIMITED 200 VISIBLE TO THERMAL 24

25 Laboratory Set up of Hyperspectral Remote sensing Sensor Lamp White Panel ASD Spectroradiometr Laptop Reflectance spectra of clay minerals and micas contains distinctive absorption features (T shaped symbols) due to the bending of Al-OH and Mg-OH bonds. Such features help in discriminating between such minerals of hydrothermal and sedimentary process. 25

26 Reflectance spectra of carbonates contains distinctive absorption features (T shaped symbols) due to vibrational transitions related to C-O bonds. Most distinctive features is near 2.35 microns, which helps in discriminating between carbonates and clays. Lab spectra of few rockktypes of Sakoli belt 26

27 Microphotograph of Serpentinite Serpentinite: Absorption point at: 1391 nm, 1980 nm, 2107 nm, 2140 nm, 2328 nm Hornblendite: absorption feature at: 1379 nm, 1907 nm, 2305 nm, 2385 nm Microphotograph of Hornblendite 27

28 Microphotograph of Talc- Tremolite-Serpentine schist Talc-Tremolite-Serpentine schist: Absorption at: 1394 nm, 1910 nm, 2325 nm Microphotograph of Tonalitic Rock Tonalitic rock: Absorption feature at: 1408 nm, 1920 nm, 2205 nm. 28

29 Field signature collection Chitradurga Granite 29

30 Argillite Metabasalt 30

31 Metabasalt JN Kote Granite 31

32 Spectra of J.N.Kote Granite Spectra of Marble 32

33 Spectra of Dolomite Mineral abundance map around Dighori Moti & Sakra village (55 P/13) 33

34 Granitoids identified through Crosta Technique: G Cultivated land Forest Cover G Cultivated land G-Granite Cultivated land G SUMMING UP Remote sensing and image analysis can be effectively utilised to map the litho types. Lineament fabric from satellite data product can be used for assessing the density and frequency of fracture/joint system to evaluate the dimensional stones in terms of their suitability. Geomorphological map can be used for study of landforms and their correlatibity with granitoids/basic rocks/carbonates /quartzites. The hyperspectral data can be used for mapping the compositional variations in granitoids and to map different carbonate rocks dolomites/calcitic types. 34

35 Thank you you Ternary Image Map Geological Map 35

36 HUNGUND-MUDHOL AREA, PARTS OF KARNATAKA The aeromagnetic map clearly brought out the extensions of the Hungund- Kustigi Schist belt in N-W direction under the Kaladgi sediments Significant Uranium anomalies around Nidagundi 36

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38 Flow banding within Rhyolite exposed near Shankarpur village Volcanic flow of Rhyolite exposed near Markandi temple in Waingangā river bed Photo-micrograph of Rhyolite Enhanced Thematic Mapper plus (ETM+) Landsat 7 Wavelength (micromete rs) Resolution (meters) Band Band Band Band Band Band * (30) Band Band Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor Bands Band 1 - Coastal aerosol Wavelength (micrometers) Resolution (meters) Band 2 - Blue Band 3 - Green Band 4 - Red Band 5 - Near Infrared (NIR) Band 6 - SWIR Band 7 - SWIR Band 8 - Panchromatic Band 9 - Cirrus Band 10 - Thermal Infrared (TIRS) 1 Band 11 - Thermal Infrared (TIRS)