INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES Volume 2, No 3, 2012

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1 INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES Volume 2, No 3, 2012 Copyright 2010 All rights reserved Integrated Publishing services Research article ISSN Application of Remote Sensing for delineation of Uranium bearing Vempalli dolomites in and around Tummalapalli area, Cuddapah Basin, India Raghu Babu. K, Sudarsana Raju. G Department of Geology & Geoinformatics, Yogi Vemana University, Kadapa, A.P.India dr.kr@rediff.com ABSTRACT The Uanium mineralization within the Vempalli dolomites of Cuddapah Super group in Mabbuchintalapalli,, Tummalapalli area falling in the Survey of India Toposheet No. 57 J/7. The Remote Sensing data obtained from IRS P6 LISS III imagery of both the areas is taken as reference for the Interpretation studies. The Remote Sensing data obtained from IRS P6 LISS III imagery of both the areas is taken as reference for the Interpretation studies. The associations of alteration processes throughout and near the mineralized sectors appear to play an important role in the distribution and localization of the mineralization. The aim of this study was to assess the effectiveness of LISS III data for detecting alteration zones as well as Uranium mineralization in parts of Cuddapah basin. Image processing techniques were applied on the digital subset LISS III data covered studied areas. These techniques generated several products of enhanced satellite imagery such as ratio images, principal component analysis and edge enhancement techniques which have been successfully used in the lithological discrimination of alteration zones and uranium bearing dolomites, structure, geomorphology, alteration zones etc., of the study area. Extensive field geologic studies in the pronounced zones delineated by the image lead to the identification of mineralized locations. Key words: Localization, Cudddapah Basin, Alteration zones, Uranium 1. Introduction Digital image processing, onscreen interpretation and GIS, applied to the IRS P6 LISS III imagery of Tummalapalli areas of Cuddapah basin for mineral mapping. False colour composite, principal component, band ratio, edge enhancement, highlighted areas of hydrothermal alteration were successfully applied and results integrated with available previous data. The interpretation is not restricted to identifying object on the image but, it also usually includes determination of their relative locations and extents. A systematic study of satellite images usually involves a consideration of two basic elements, namely image elements and terrain elements. Image interpretation of terrain elements and image elements with identification of geological features based on variations in spectral signatures help in satellite based geological mapping. Altered rocks were recognized by their appearance in the visible spectral bands in remote sensing (Subhash babu et al., 2009). Most mineral deposits are accompanied by hydrothermal alteration of country rocks. The ability to discriminate between hydrothermally altered and unaltered geologic materials is of considerable practical value, particularly in mineral exploration and assessment studies. Reflection spectra of particular mineral that commonly occur in hydrothermally altered rocks and soils were recorded to display their features at their natural spectral bandwidths in the near-infra red Submitted on December 2011 published on February

2 from 1.3 to 2.4µm (Hunt, 1979). In addition to information available in the range 0.4 to 1.1 µm, very useful information exists through the near-infrared range from 1.1 to 2.5 µm, due to the vibrational processes occurring in some of the molecular groups that constitute minerals and rocks (Hunt, 1979). 2. Study area The Study area, Mabbuchintalapalli and Tummalapalli are situated in the southern margin of the Cuddapah basin over the Vempalli formation underlain by Gulcheru quartzies and Penunsular Gneissic Complex in the Survey of India toposheet No. 57 J/7 between longitudes `00``, `00`` and latitudes `00``, `00``/ `00``covering an area about 1200 Sq.km (Figure 1). 3. Methodology Figure 1: Location & Geology The approach involves database preparation, digital classification and systematic on-thescreen visual interpretation of space borne multispectral digital data. A flowchart portraying the methodology adopted in the present study is appended as (Figure 2) is given hereunder. 843

3 3.1 Preparation of Database Figure 2: Flow chart showing the methodology Preparation of database involves geo-referencing and fusion of multi-spectral and panchromatic digital data. Details of various steps involved are as follows. 3.2 Geo-referencing The IRS P6 LISS III data were digitally co-registered to Survey of India toposheet 57J/7 and 57 J/13 at 1:50,000 scale using ERDAS/IMAGIN software. 3.3 Preliminary Digital Analysis For objective assessment of the sediment detachment, information on the land cover, slope, management practices, soil erodibility is essential. Hence preliminary interpretation of satellite digital data was carried out to delineate various landform categories in co-junction with the Survey of India (SOI) toposheet. Simultaneously, preliminary interpretation was also done for mapping soil properties exploiting the inherent relationship between lithology, physiography and land cover. 3.4 Ground Truth Collection Ground truth mission was subsequently planned to establish the relationship between image elements, namely colour, texture, shape, size, shadow, pattern, association, etc, and various features identified during preliminary digital analysis. 844

4 3.5 Final Digital Analysis Different interpretation techniques for inferring various features were applied to the IRS P6 LISS III satellite imagery of study areas by using ERDAS/IMAGIN and GIS software. 1. Subsetting: the study area present study has been separated from the imagery by the technique of subsetting (Figure 3). 2. Edge enhancement techniques: both high pass and low pass filtering techniques were applied for delineating the fracture zones, fault zones, linear features which are probable mineralized zones (Figure 4). 3. PC analysis: water bodies and land patterns are distinct in PC analysis than the False Colour Composite. Lithological and alteration zones discrimination is more significant in PC in contrast to the FCC (Figure 5). 4. Band ratio technique: this technique is adopted to get the reflectance properties of alteration minerals and uranium mineralization in the present study area (Figure 6). 5. Texture: Textural classification studies are useful for the study of frequency of tonal changes in an image. Texture is produced by an aggregate of unit feature which is product of individual shape, size, pattern, shadow and tone (Figure 7). 6. The reflectance curves of Pyrite and Chalcopyrite drawn between wavelength and reflectance in the image. The graphs showing peaks for pyrite at 0.3 µm to 2.5 µm where as for chalcopyrite at 0.5 µm to 3.0 µm (Figure 8). Figure 3: Subset image of Tummalapalli area 57 j

5 Application of Remote Sensing for delineation of Uranium bearing Vempalli dolomites in and around Figure 4: 7x7 Highpass Filtering Figure 5: 5 PCA of Tummalapalli area 57J07 846

6 Application of Remote Sensing for delineation of Uranium bearing Vempalli dolomites in and around Figure 6: IR/R of Tummalapalli area 57J07 Figure 7: Texture 847

7 3.6 Geology Figure 8: Reflectance values of Pyrite and Chalcopyrite For investigating the lithology of the study area, the IRS P6 LISS III imagery has been geometrically corrected and represented in everest projection using the Survey of India Toposheet Nos. 57 J/7 and 57 J/13 on the scale of 1:50,000. Then the imageries have been exported to Geographical Information System for delineating lithology for the preparation of geological map (Figure 3). The geological succession of the study areas is as follows. Table 2: Geological succession of the study area CUDDAPAH SUPER GROUP Nandyal shale KURNOOL GROUP Koilakuntla limestone Unconformity Cumbum formation NALLAMALAI GROUP Bairenkonda quartzite Unconformity Gandikota quartzite CHITRAVATHI GROUP Tadipatri shale Pulivendla quartzite Disconformity PAPAGNI GROUP Vempalli formation Gulcheru quartzite (After Nagaraja Rao et al 1981) 848

8 5. Interpretations in Mabbuchintalapalli, Tummalapalli area 5.1 Geology The geological formations in Mabbuchintalapalli, Tummalapalli area composed of Peninsular Gneissic Complex overlain by cyclic sequence of conglomerate quartzite and shale. The sequence is as follows Peninsular Gneissic Complex 1. Cherty Dolomite 2. Limestone 3. Quartzite 4. Peninsular Gneissic Complex The Cuddapah Supergroup comprising cyclic sequences of conglomerate-quartzite-shale with minor carbonates (stromatolytic dolomites) and basic volcanic and intrusive was deposited over denuded and upturned edges of the Archaean gneisses, granites and supracrustals known as Peninsular Gneissic Complex. These rocks show dark tone in the VNIR range (Yousif, M.S.M., and Shedid, G.A.,1999). Alteration products comprise clays which possess absorption bands in the SWIR region ( µm). Silicate absorption bands occur in the TIR region ( µm) Quartzite They show light to dark tone, coarse texture, coarse drainage and very sparse vegitation in the imagery. Extensively developed talus is observed in the imagery on the slopes of hills composed of these rocks. This litho unit belongs to Gulcheru quartzite and Pulvendla quartzite, with wide spread joints and structurally controlled drainage pattern. Sparse to scrub vegetation is observed Shale Shales show medium to dark tone, fine to medium texture, fine textural drainage, closely spaced bedding gives some linear pattern in the digital imagery. This litho unit observed in the study area at to two stratigraphic horizons over the Nallamalai group and asigned as,nandyal shale formation of the Kurnool group and the other occurring as intercalation with the phyllite rock unit belongs to the Cumbum/Pullsmpet formation of the Nallamalai Group forms as a valley and ridge forms indicating differential erosion of the litho units Limestone Limestone show grey tone, medium and mottled texture, have less surface drainage, with sink holes, dolines, solution channels etc., sometimes show contorted bedding. Limestone exposed in the study area represents both Nallamalai group and Kurnool group. Limestone patches occurring as small patches in N-E part of the study area belongs to the Cumbum Formation of Nallamalai group where as that occurring in the western part of the study area belongs to the Koilakuntla formation of the Kurnool group. 849

9 5.1.5 Dolomite This litho unit belonging to the Cumbum Formation of the Nallamalai group is exposed at the North-North eastern part of the study area forming a small dome like structures. 5.2 Structures Space imageries and space photographs cover large areas. Hence structures of regional level are easily descernible on these. Different structural elements interpreted in the structural map (Figure 5) through the digital imagery in the study are as follows Horizontal planar structures They show tonal banding representing lithological banding and bedding, contoured appearance of tonal banding on low dipping beds and tonal banding accentuated by vegetational banding Linear structures In the digital imagery joint, fault or unconformity can be marked as linear traces. Unclassified linear features are referred to as lineaments. They can be recognized by i. Joints: Joints are expressed as lineaments, rectangular, parallel or linear drainage pattern, linear vegetation pattern or short criss cross linear patterns. Joints are well expressed in quartzites in the study area than other rock units. There are two sets of joints are present viz., bedding joints and transverse joints. ii. Faults: In the digital imagery most of the faults are expressed as straight or gently curved lines known as photolineaments, linear depression and linear scarps, alignment of vegetation, straight segments of streams and waterfalls across streams, alignment of ponds and springs, normally vegetation on two sides shall be different when the lithologies are different. Drainage pattern on two sides of the fault shall be different, change in land form on either side of the lineament, lithological change shall also be reflected by tonal change and offset of ridges, beds or structures Folds Fold structures can be interpreted from orientation of dipping planes, land form, drainage, shape and pattern. Change in pattern of dips is also indicative of folded nature of the terrain. Change in dips is also indicative of folds Mineralization The basal Gulcheru conglomerates at the base of the Cuddapah basin were found to be thoriferous. The uranium mineralization is hosted by impure phosphatic dolostones of Vempalli Formation of Papaghni Group. It extends from Chelumpalli in the northwest to Maddimadugu in the northeast over a belt of 160 km with promising mineralization at Tummalapalle, Rachakuntapalli and Gadankipalli in the central part. 5.3 Significant Interpretations from Digital imagery 850

10 The selected image subset is prepared as shown in Figure supervised and unsupervised classifications were applied to study different rock unit in the study area. Various rock units have been delineated by studying the nature of fracture, faulting, texture of the rocks, drainage patterns and various thematic maps have been prepared for identification of uranium baring dolostones of Vampalli Formation. 5.4 Alteration minerals The study area in the image showing spectral signatures significant for the minerals like pyrite, chalcopyrite. The reflectance curves of Pyrite and Chalcopyrite drawn between wavelength and reflectance in the image. The graphs showing peaks for pyrite at 0.3 µm to 2.5 µm where as for chalcopyrite at 0.5 µm to 3.0 µm (Figure 8). 5.5 Uranium mineralization The granitic rocks are considered as one for the most important source for uranium deposits (Shalaby, M.H., et al 2009). The present work concerns with Mabbuchintalapalli, and Tummalapalli areas, where the basement is granitic followed by Gulcheru quartzites, Vempalli limestones and dolomites. Image processing techniques were applied in this work to define main characteristics features of the dolomite rock bearing uranium mineralizations. The IRS LISS III image was used to recognize and map the investigated areas. The colour composite images and application of principal component analysis of LISS III data lead to identify and characterize the uranium bearing dolomite in the investigated areas. 5.6 Conclusions Remote Sensing is largely used for mineral exploration (Rowan and Bowers 1995; Abdelhamid and Rabba 1994; Kaufmann, 1988; Abrams, 1984; Rowan and Kahle, 1982), especially for (i) mapping regional lineaments, (ii) mapping local fracture pattern that may control individual ore deposits (iii) detecting hydro-thermally altered rocks associated with ore deposits and (iv) providing basic geologic data. Various digital image processing procedures were applied such as ratioing, PC analysis. In the present an IRS P6 LISS III satellite image covering an area of approximately 720 sq. km pertaining to the Survey Of India toposheet no. 57 observed 57j/14 between longitudes of ` and `, latitudes of and ` was digitally processed and interpreted to elucidate the lithology, structure and geomorphology of the study area. Geological elucidation consists of tonal demarcation of the various geological members of the region mainly Quartzite, Limestone, Dolomite, Shale/phyllite. Observed linear features were classified into various categories viz., faults, fractures/joints, lineaments. Delineation of these rock units is illustrated by texture analysis of the image using ERDAS Imagine software. The Principal Component Analysis (PCA) enumerates the alteration minerals around the mineralized zone and they are more enunciated by the Band Rationing technique. In the present study the filtering techniques adopted to delineate the fractures and fault zones. These studies are more useful in narrowing down the mineralized zone. 6. References 1. Abdelhamid, G., and Rabba, I., (1994), An investigation of mineralized zones revealed during geological mapping, Jabal Hamra Faddan-Wadi Araba, Jordan, using Landsat TM data, International Journal of Remote Sensing, 15, pp

11 2. Abrams, M.J., (1984), LandSat 4, Thematic Mapper and Thematic Mapper Simulator data for a Porphyry Copper Deposit, Photogrammetric Engineering and Remote Sensing, 50, pp Hunt, G.R., (1979), Near Infrared ( µm) Spectra of altered minerals potential for use in Remote Sensing, Geophysics, 44, pp Kaufmann, H., (1988), Mineral exploration along the Aqaba-Levant structure by use of TM data; concepts, processing, and results, International Journal of Remote Sensing, 9, pp Nagaraja Rao, B.K., and Ramalingaswamy, G., (1976), Some new thoughts on the Stratigraphy of Cuddapah Supergroup Seminar on Kaladgi-Badami, Bhima and Cuddapah Supergroup, Mysore, pp abstracts. 6. Rowan, L.C. and Bowers, T.L., (1995), Analysis of linear features mapped in Landsat Thematic Mapper and side-looking airborne radar images of the Reno, Nevada 1 by 2 quadrangle, Nevada and California-implications for mineral resource studies, Photogrammetric Engineering and Remote Sensing, 61, pp Rowan, L.C., and Kahle, A.B., (1982), Evaluations of micrometer. Multispectral scanners images of the East Tintic mining district, Utah, for mapping hydrothermally altered rocks, Economic Geology, 77, pp Shalaby, M.H., Bista, A.Z., Roz, M.E. and El Zalaky M.A., (2009), Integration of Geologic and Remote Sensing Studies for the discovery of Uranium Mineralization in Some Granite Plutons, Eastern Desert, Egypt Journal of Earth Science, 1, pp Subhash Babu, Raushan Kumar and Siva Subramanyam K.A., (2009), Identification of Hydrothermal altered zones for Mineral exporation, Vector1media.com 10. Yousif, M.S.M., and Shedid, G.A., (1999), Remote sensing signature of some selected basement rock units from the central eastern desert of Egypt, Egypt journal of Remote Sensing & space Science, 1, pp