Discrimination of low-grade magnetite ores using remote sensing techniques

S. Rajendran, A. Thirunavukkaraasu, B. Poovalingaganesh, K. Vinod Kumar, G. Bhaskaran

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The remote sensing community in geology is widely using the Multispectral Landsat Thematic Mapper (TM) data which has a wider choice of spectral bands (six between 0.45 and 2.35 &mgr;m, plus a thermal infrared channel 10.4-12.5 &mgr;m). These were evaluated for low-grade magnetite ores mapping over the high-grade granulite region of Kanjamalai area of Tamil Nadu state, India. The Fourier Transform Infrared (FTIR) spectroscopy data (0.4-4.0 &mgr;m) for powders of the magnetite ores exposed with granulite rock and published spectral reflectance data were used as guides in selecting TM band reflectance ratios, which maximize discrimination of magnetite ores on the basis of their respective mineralogies. The study shows that the weathering mineralogy of magnetite ores causes absorption features in their reflectance spectra which are particularly characteristic of the near infrared. Comparison of TM data with field and petrographic observations shows the presence of magnetite and aluminosilicate minerals & show strong absorption at 0.7-1 &mgr;m wavelength spectral region & increase in the product of two TM band ratios: band 5 (1.55-1.75 &mgr;m) to band 4 (0.76-0.9 &mgr;m) and band 3 (0.63-0.69 &mgr;m) to band 4 (0.76-0.9 &mgr;m). Various computer image enhancement and data extraction techniques such as interactive digital image classification techniques using color compositing stretched ratio, maximum likelihood and thresholding statistical approaches using Landsat TM data are used to map the low-grade magnetite ores of the granulite region. The field traverses and local verification enhanced to map the other rock types namely granulites and gneisses of the study area.

Original languageEnglish
Pages (from-to)153-162
Number of pages10
JournalJournal of the Indian Society of Remote Sensing
Volume35
Issue number2
DOIs
Publication statusPublished - Jun 2007

Fingerprint

magnetite
discrimination
remote sensing
granulite
Landsat thematic mapper
reflectance
Tamil
spectral reflectance
aluminosilicate
image classification
digital image
FTIR spectroscopy
rock
ore
near infrared
mineralogy
weathering
geology
India
wavelength

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Geography, Planning and Development

Cite this

Discrimination of low-grade magnetite ores using remote sensing techniques. / Rajendran, S.; Thirunavukkaraasu, A.; Poovalingaganesh, B.; Kumar, K. Vinod; Bhaskaran, G.

In: Journal of the Indian Society of Remote Sensing, Vol. 35, No. 2, 06.2007, p. 153-162.

Research output: Contribution to journalArticle

Rajendran, S. ; Thirunavukkaraasu, A. ; Poovalingaganesh, B. ; Kumar, K. Vinod ; Bhaskaran, G. / Discrimination of low-grade magnetite ores using remote sensing techniques. In: Journal of the Indian Society of Remote Sensing. 2007 ; Vol. 35, No. 2. pp. 153-162.
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