Lithological Discrimination and Mapping Using Aster Swir Data in The Tundi Area, Jharkhand

: ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) multispectral data is utilized in mineralogical and lithological mapping along with alteration zone mapping. The present study is carried out using ASTER data, which has shown the effectiveness SWIR spectral bands of ASTER data in lithological mapping. Field validation is carried out in the areas where lithological updation was expected from the sspectral analysis. From the band ratios, argillic, ferric, phyllic and propylytic alteration zones were demarcated. Thus, ASTER SWIR bands coupled with the advanced image enhancement techniques are recommended as a rapid and cost effective tool for lithological discrimination and mapping in the hostile terrain of Dhanbad and other geological areas.


Introduction
Remotely sensed data can be utilized in varied geological applications such as alteration zone mapping, mineral potential and lithological discrimination 10,38,50,52,54,60 .Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) launched in 1982 and 1999 with 5 and 8 spectral channels are some of the Spaceborn multispectral sensors utilized for such applications 12,52 .Since 2000, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) multispectral data have been used in mineralogical and lithological studies (Ninomiya, 2002, 2004; Rowan et al., 2003; Rowan  and Mars, 2003).The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five instruments on the U.S. Terra spaceborne platform (the other instruments are the Moderate Resolution Imaging Spectroradiometer (MODIS), Clouds and the Earth's Radiant Energy System (CERES), Multi-angle Imaging Spectro Radiometer (MISR), and Measurement of Pollution in the Troposphere (MOPITT)).Launched in December 1999, ASTER has been continuously acquiring image data for 20 years.ASTER is a joint project between Japan's Ministry of International Trade and Industry (MITI) (later changed to Ministry of economy, Trade and Industry (METI)) and the U.S. National Aeronautics and Space Administration (NASA) 29 .
In 2003, Rowan and Mars were one of the first researchers to report on lithologic mapping using ASTER data, over the rare earth mineral deposit at Mountain Pass, California 45 .Using all 14 ASTER bands, they were able to distinguish calcite from dolomite, mapped skarn deposits and marble in the contact metamorphic zones, distinguished Fe-muscovite from Al-muscovite in the granites and gneisses, and discriminated quartzose rocks.None of these discriminations could be accomplished with Landsat TM data, due to the lack of multispectral SWIR and TIR spectral bands.Watts and Harris 53 applied this method to map granite and gneiss in domes in the Himalayas.Yamaguchi and Naito 57 developed spectral indices using orthogonal transformation with ASTER SWIR bands for lithologic mapping.Their method relied on band ratios and thresholding.Wherever there were good rock exposures, ASTER data produced good results.Analyzing all of the ASTER spectral bands, Byrnes et al. 6 mapped volcanic lava

IJFMR23069468
Volume 5, Issue 6, November-December 2023 3 using TIR data.Bertoldi et al. 5 used field and laboratory data to guide processing of ASTER data to map lichen-covered granitic rocks in the western Himalayas.Their maps were based on characterizing spectral differences from various lichens, with spectral characteristics of muscovite.In the Dahab Basin, Egypt, Omran et al. 33 used band ratios of ASTER VNIR, SWIR, and TIR data, combined with field investigations, to map and separate granitoid rocks of Cambrian and Cretaceous ages.They revised and updated existing geologic maps by adding rock units and re-interpreting the geologic history.Zheng and Fu 59 used band ratios of ASTER SWIR and TIR data to separate alkali-feldspar granite, granite, granodiorite, and monzogranite.These distinctions relied on determination of silica difference expressed in the TIR bands.Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) has three spectral bands in the Visible/near Infrared (VNIR) region, six spectral bands in the Shortwave Infrared (SWIR) region and five spectral bands in the Thermal Infrared (TIR) region with 15m, 30m and 90m spatial resolution which can provide a new prospective of investigating earth's surface material for various applications 10,12,47,54 .ASTER data is most suitable for geological applications because of the enhanced resolutions, high Signal to Noise Ratio (SNR), the effective spectral coverage and global data availability.The three spectral bands of ASTER play an important role in various geological applications such as the VNIR region provides spectral features of transition metals such as iron, SWIR region is very effective for analyzing spectral characteristics of carbonate, hydrate and hydroxide minerals, and TIR region is effective for characterization of silicates 7,11 .These three spectral bands help in the identification of hydrothermal alterations such as propylitic, argillic, phyllic and potassic zone 4,36,37,40 .To obtain the lithological, mineral and hydrothermal alteration maps with reasonable accuracies, various image enhancement techniques have been well employed on ASTER datasets 10,13,21,36,37,38,58 .
In this study, focus has been emphasized on application of PCA, MNF and on ASTER SWIR data to discriminate the various lithological units.The objective of the present study is to demonstrate the utility of ASTER SWIR data for lithological discrimination and mapping in the Tundi area, Jharkhand.The major part of the study area is covered by CGC and Barakar sandstone.The CGC mainly consists of different variants of granite /gneisses of composite character, porphyroclastic granite gneiss (PCG) with enclaves of metasedimentary and metabasic rocks, intrusive basic rock, and pegmatite and vein quartz.CGC is overlain by Gondwana Supergroup of rocks with a profound nonconformity in the study area.These granite-gneisses show diverse petrography and petrochemistry (Ghosh and Sengupta, 1988; Bandyopadhyay and Bandyopadhyay, 1990).Heterogeneity also exists in terms of structure and metamorphism (Pyneet al., 1991).The CGC rocks mainly have undergone amphibolite grade of metamorphism, but the grade of metamorphism increases from south to north from lower amphibolite to granulite facies.CGC shows complex amalgamation of granite with Granulite facies rock in this area (Acharya, 2001, Chakraborti and Huin, 2008).In the studied area Gondwana Supergroup is represented by Barakar Formation.Barakar Formation is represented by fining upwards cycles of coarse pebbly, poorly sorted arkosic-subarkosic calcareous sandstone, siltstone, carbonaceous shale and coal.Barakar sediments show excellent primary sedimentary structures in quarry sections in the north western part.Fining upward cycles, large scale tabular cross bedding, epsilon cross bedding are indicative of meandering channel facies.Coarse to fine grained sandstones exhibiting large scale cross bedding, horizontal parallel bedding are considered to represent point bar deposits formed from lateral accretion of stream bed load on sideward migration of meandering channel (Smith, 1970).Siltstones, carbonaceous shales grading upwards into coal indicate over bank deposits.Lower Gondwana fossils such as Glossopteris can be seen in shales of Barakar Formation.Rock types such as granite, granite gneiss, quartz, phyllite, gabbro, dolerite (Chhotanagpur Gneissic Complex) and sandstone (Barakar formation) are noticed in the study area during field work.The trend of quartz hillocks present in the given area is in the NW-SE direction whereas the trend of granite hillocks is in the E-W direction.Barakar is the major river flowing through the study area and they are flowing in the SE direction.

Lithology 2.3.1 Unclassified Metamorphics
Unclassified Metamorphic rocks occur as linear band /bodies within gneisses and follow the regional trend of foliation and include amphibolite, hornblende schist, mica schist, feldspathic quartzite and calc-silicate rocks.

Chhotanagpur Gneissic Complex (CGC):
Granite gneisses are the most dominant rock types in the area.Gneisses are medium to coarse grained, which constitute the basement for the sedimentaries, to form the undulating topography of the area under consideration.Different varieties of gneisses present in the area include biotite granite gneiss, hornblendic granite gneiss and sillimanite granite gneiss and all of them are garnetiferous.Biotite granite gneiss often shows schistose character with intricate folding and crenulation.Sillimanite granite gneiss is more or less similar to biotite granite gneiss except that it contains considerable quantity of sillimanite.All these rock types are medium to coarse grained and occur mainly in the lower contours.They are structurally disturbed, tightly folded and intensely faulted.

Calc Granulite:
In the study area, to the south of Sangramdih, ridges of Calc granulite outcrops which are highly ferruginised and limonitised are evident.Chemogenic precipitation has occurred which resulted in a strong alteration in the outcrops.At places, iron concretions are observed.

Amphibolite:
Outcrops of Amphibolites occur as enclaves in the Chhotanagpur Gneissic Complex (CGC) which are devoid of alterations.Occasionally, incipient gneissosity has been observed, defined by thin alternate bands of Quartzo-feldspathic and Amphibolite-Biotite rich layers.

Quartzite:
On the south of Bandarchua hill slope, Quartzite boulders are exposed where boxwork vein structures are observed which are strongly ferruginised and limonitised.

Gondwana Super Group:
Gondwana Super Group is represented by Barakar Formation composed of sandstone, grit, shale, carbonaceous shale and coal seams.Outcrops of Buff coloured, ferruginised, fine grained, regularly sorted Sandstone along the banks of Barakar River, where porphyoblasts of Quartz are observed.These are highly matured with ferruginisation at surface.At places, grey coloured Sandstone is evident which is irregularly sorted, coarse angular grains and less matured indicating a close by provenance.

Intrusives: Intrusive rocks of Proterozoic age include pegmatite, quartz vein and dolerites of Jurassic to Cretaceous age. Dolerite
A number of dolerite dykes are seen cutting across the basin.The dolerite dyke forms a small ridge at Karitan village i.e. in the south eastern part of the Toposheet characterised by dark colour index, trending 130° sub-parallel to Barakar River.

Structures
Different structural features in the area include foliation, bedding, joints, folds and faults.A. Foliation: It is the most common planar structure preserved in schist and gneisses.B. Bedding: Developed in Sedimentary rocks of Gondwana Supergroup.C. Joint: Joints are extensively developed in the area.They are strike, dip and oblique joints having steep to vertical dips.Two sets of perpendicular joints are visible in Buff Sandstone of Barakar Formation along the banks of Barakar River where bedding is prominent with cross stratification and oscillatory ripple marks.PCD, i.e.Convolute Laminations are dominant.D. Fold: Small scale antiformal folds are developed in the schistose rocks.In the outcrops of Calc granulite, two generations of folds are observed where all the four limbs are almost sub-vertical.The first generation fold is subparallel with the regional trend of Satpura orogeny.S and Z type of folds are observed with fold interference pattern in Granite gneisses of Chhotanagpur Gneissic Complex (CGC).E. Shear Zone: Shear zone is also noticed in granite gneiss which shows the dextral as well as sinistral sense of shearing.Some of the nala sections show the boudinage in the gneiss which were developed in the extensional regime, at few places the necking zones also present.F. Boxwork: In the outcrops of Calc granulite, boxwork vein structures are observed which indicates that the area might have been affected by remobilisation of hydrothermal fluids.

III. Materials and Methods
A cloud free Level 1B (geometric and radiometric corrected) Advanced Spaceborne Thermal Emission and Reflection Radiometer data acquired on 2007 was obtained from USGS website for the study.The data consists of 3 VNIR, 6 SWIR and 5 TIR spectral bands.The data is georeferenced in the UTM projection for theWGS-84 ellipsoid.All pre-processing of Level 1B ASTER data were carried out using ENVI 4.8 software and GIS software packages.The detailed specification of the ASTER sensor is given in Table 1.Collateral datasets such as the Geological Survey of India (GSI) district resource map (1:250000 scale) and published literature of Dhanbad district of Jharkhand was used as a geological guide to interpret and asses the image results.Due to the challenging topography and hostile conditions of the study area only few locations were visited to verify the image derived lithological map.

ASTER Reflectance Calibration
Processing of ASTER L1T data includes atmospheric correction and stretching of the images.ASTER VNIR bands were calibrated using IAR (Internal Average Relative Reflectance) method and short wave infrared bands (SWIR) of ASTER data are calibrated to apparent reflectance using log residual method.Log residual (LR) method corrects for instrument gain, topography and albedo effects from radiance data.The log residual correction is considered as effective calibration method to correct multiplicative atmospheric effects such as transmittance etc. and this correction method are suitable for mineral mapping.But the visible near infrared (VNIR) domain is affected by the additive atmospheric noise.Therefore, internal average relative correction method is applied to VNIR (Azizi et al.,2010) channels of the data.The reflectance image is used for further processing for the generation of band ratios, principal component analysis and spectral analysis.The spectral curves of minerals are characterized by reflectance peak and absorption bands caused by electronic and vibrational processes with their crystal lattices.It is seen that iron oxides have a reflectance peak in the visible red (0.73 microns) and absorption feature near 0.9 microns and 0.4microns.

Band Ratios:
In ASTER image, Band ratio was used to enhanced the spectral differences between band to band and reduces the topographic effect.The primary purpose of such ratios is to enhance the contrast between objects by dividing brightness values at peaks and troughs in a spectral reflectance curve.Some commonly used band ratio method for delineating, iron, carbonate, agrillic, silicates and silica alteration using ASTER multispectral data.To extract the most useful spectral information from the ASTER bands and to characterize geological features, different types of band combinations and image processing techniques are applied which includes: (1) Red-Green-Blue (RGB) band combinations, (2) band ratios and logical operations.ASTER imagery processing is a valuable tool for mapping different lithological units, hydrothermal assemblages and key ore-related hydrothermal alteration minerals.

III. Conclusion
In this study, ASTER data was analyzed for identification of hydroxyl, carbonate and iron-bearing mineral phases and to map on the basis of the nature & shape of diagnostic absorption feature of mineral.The study has shown the effectiveness SWIR spectral bands of ASTER data in lithological mapping.Thus, ASTER SWIR bands coupled with the advanced image enhancement techniques are recommended as a rapid and cost effective tool for lithological discrimination and mapping in the hostile terrain of Dhanbad and other geological areas.
The study area covering parts of Toposheet nos.72L/08, 72L/12, 73I/05 & 73I/09 belongs to Dhanbad district, Jharkhand and is bounded by A (24° 4' 8.151" N, 86° 19' 0.713" E), B (24° 4' 15.893" N, 86° 37' 10.362" E), C(23° 54' 55.795" N, 86° 18' 58.815" E) and D (23° 55' 0.041" N, 86° 37' 3.132" E).Location of the Study Area • Email: editor@ijfmr.comIJFMR23069468 Volume 5, Issue 6, November-December 2023 4 The Precambrian Eastern Indian Shield (EIS) (Saha et al., 1988; Saha, 1994; Mukhopadhyay, 2001) is characterized by complex geological and tectonic history.It consists of mainly three geological provinces-(1) Singhbhum craton characterized by Archaean TTG crust (OMTG), older (Iron Ore Group) and younger supracrustals (Singhbhum Group, Dhanjori Group) and cratonic massif of Singhbhum and Chakradharpur granite.(2) Proterozoic Fold Belt (PFB)/ North Singhbhum Mobile Belt (NSMB) and (3) Chhotanagpur Granite Gneiss complex (CGC).The Proterozoic fold belt is mainly a volcano-sedimentary assemblage of Palaeoproterozoic to Mesoproterozoic age.The northern margin of Singhbhum craton with PFB at its north is marked by prominent ductile shear zone known as Copper Belt Thrust (Dunn and Dey, 1942) or Singhbhum Shear Zone (Sarkar and Saha, 1962).Singhbhum Craton is bounded in the north by Chhotanagpur Gneiss, forming the eastern extension of the Satpura mobile belt or Central Indian Tectonic zone.The northern contact of PFB with Chhotanagpur Granite Gneiss Complex (CGC) is marked by another E-W trending ductile shear zone (Dunn and Dey, 1942; Bhattacharya, 1989), known as Tamar Porapahar Shear Zone/ South Purulia Shear Zone (SPSZ).The huge mass of CGC occurring at the north of PFB has a different tectono-metamorphic history.It is characterized by presence of different variants of granite, gneisses and granulites.A number of discrete ductile shear zones present within CGC.Among them the E-W trending brittle -ductile shear zone extending over 100 Km from Jhalda in the west through Malthol to Raghunathpur and further east to Santuri is the most significant.It is termed as North Purulia Shear Zone (NPSZ) (Prasad, 1988; Sarkar et al., 1998, Sarkar, 2009, Chakraborti and Huin, 2008).In the northern part, CGC rocks are overlain by Gondwana Supergroup.The Gondwana Basins of Peninsular India contain a thick pile (~200 to 4000m) of clastic sediments preserved in graben /half-graben setting bounded by high angle normal faults Gondwana sediments are represented by a thick sequence of shallow water, fluviatile and lacustrine sediments having an aggregate thickness of about 6000-7000 m with characteristic floral-faunal content and spanning in age from Upper Carboniferous to Lower Cretaceous.It is essentially a continental succession and its upper and lower boundaries cannot be precisely defined chronostratigraphically, as floral assemblages are long-ranging and the land vertebrate remains are also sporadic in occurrence (mainly restricted to middle part of the succession).The lower and upper contacts of Gondwana sediments also do not coincide with the Standard Time Scale.This continental succession of sedimentary deposits of Southern hemisphere is unique in a way and has been informally designated as the "Gondwana Sequence".The study area exposes rocks of Unclassified Metamorphics, Granite gneiss and migmatites belonging to Chhotanagpur Gneissic Complex, Proterozoic intrusives, e.g.metanorites and dolerites, Talchir Formation and Barakar Formation of Gondwana Supergroup.(Source: compilation of TS no.72L/12 by Shri C. Parathasarathi, Geologist) • Email: editor@ijfmr.comIJFMR23069468 Volume 5, Issue 6, November-December 2023 5 ASTER band combinations (RGB) such as 468, 321 and 731, provide a rough guide to distinguish different geological features from an area.Particularly, ASTER False-color composite 468 (RGB) images typically show argillic-and phyllic-altered rocks as red tones, and propylitic-altered rocks as green tones due to Al-O-H (centered at ASTER band 6) and Fe, MgO-H (centred at ASTER band 8) absorption features, respectively (Ali mohammad , M., et al., 2015, Mars, 2010; Tommaso and Rubinstein, 2007).• Email: editor@ijfmr.comIJFMR23069468 Volume 5, Issue 6, November-December 2023 9 A. ARGILLIC ALTERATION (B4 +B7)/(B6 * B2) Argillic Alteration affects mainly plagioclase feldspars and is characterized by the formation of clay minerals i.e. kaolinite and smectite group (mainly montmorillonite).It typically forms below 250°C by H + metasomatism and occurs on the fringes of porphyry systems.(Fig.3.4)B. FERRIC ALTERATION (B2/B1) Ferric alteration indicates that oxidising hydrothermal fluids percolated through the rocks.The outcrops may show high reflectance values in some of the spectral regions, and also it may absorb in some other spectral regions.Supergene altered deposits typically contain limonite, goethite, hematite and jarosite.For instance, ferric iron (hematite, goethite) absorbs in the near 0.52 μm (ASTER-B1) region and high reflectance value in the 0.63-0.69μm (ASTER-B2) spectral range of electromagnetic radiation (EMR).The band ratio of B2/B1 of ASTER will be highlight ferric iron-rich zones.C. PHYLLIC ALTERATION Phyllic alteration typically forms over a wide temperature range by hydrolysis of feldspars to form sericite (finegrained white mica), with minor association quartz, chlorite and pyrite.It is normally associated with porphyry Cu deposits, but also with mesothermal precious metal ores and volcanogenic massive sulphide deposits in felsic rocks.It is typified by the assemblage quartz-sericite-pyrite. (Fig.3.6)D. PROPYLYTIC ALTERATION (B7+B9)/(B8 * B2) Propylytic alteration is a mild form of alteration representing low to intermediate temperatures (200-350°C) and low fluid/rock ratios and characterizes the margins of porphyry Cu deposits as well as epithermal.It is characterized by the addition of H2O and CO2 and locally S, with no appreciable H+ metasomatism.The pyrophyllite mineral show spectral absorption at 2.16 µm i.e., in-band 5 of ASTER data and its shoulder of absorption is at 2.20 µm i,e in band 6 of ASTER data.It shows reflectance in VNIR (band 4).(Fig.3.7)E. ADVANCED ARGILLIC ALTERATION ((B7+B9)/(B8 * B2)) General alteration represents an extreme form of base leaching where rocks have been stripped of alkali elements by very acidic fluids active in high fluid/rock ratio environments.It is characterized by kaolinite, pyrophyllite, or dickite (depending on the temperature) and alunite together with lesser quartz, topaz and tourmaline.It is commonly associated with near surface, epithermal precious metal deposits where alteration is associated with boiling fluids and condensation of volatile rich vapours to form extremely acidic solutions.(Fig.3.8)F. PCA (PRINCIPAL COMPONENT ANALYSIS) FOR SELECTED BANDS: Because multispectral data bands are often highly correlated, the principal components (PC) transformation is used to produce uncorrelated output bands.This is done by finding a new set of orthogonal axes that have their origin at the data mean and that are rotated so the data variance is maximized.PC bands are linear combinations of the original spectral bands and are uncorrelated.The ASTER PCA images with high Eigenvalue loading were selected for preparation of FCC (Fig. 3.9).IJFMR23069468 Volume 5, Issue 6, November-December 2023 10