Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Arindam Guha ¹

Affiliations
1 Geosciences Division, National Remote Sensing Centre, Balanagar, Hyderabad–500 625, IN

Abstract

No Abstract.

Full Text

     

Arindam Guha ¹, K. Vinod Kumar ¹, M. V. V. Kamaraju ¹, K. Babu Govindharaj ¹

Affiliations
1 Geosciences Division, National Remote Sensing Centre (Indian Space Research Organisation), Hyderabad - 500 625, IN

Abstract

The application of SAR data is a proven technology in geological studies but very few accounts are available in India, which can evaluate and demonstrate the utility of microwave signatures as an important tool for geological mapping. In this connection, the significance of polarization is an important parameter in enhancing geological elements. Present study reveals that the simple polarization composite prepared from different polarization channels can significantly aid the delineation of geological features as demonstrated from the Proterozoic metasedimentary sequences of Kurnool Group. The polarization colour composites reveal that different sedimentary units can be differentiated on the basis of variable back scattering return in different polarization channel. Further geological structures of regional importance can also be delineated in these colour composite images. Comparative analysis of different composite images with published geological maps, illustrates the capabilities of the microwave polarization in enhancing geological elements and how they can be used in updating geological data.

Keywords

Microwave Remote Sensing, Geological Mapping, Kurnool Group, Andhra Pradesh.

Full Text

     

Arindam Guha ¹, K. Vinod Kumar ²

Affiliations
1 Geosciences Division, National Remote Sensing Centre (ISRO), Balanagar, Hyderabad - 500 037, IN
2 Geosciences Division, National Remote Sensing Centre (ISRO), Balanagar, Hyderabad - 500 037, IN

Abstract

Coal fires are serious problem in Raniganj coalfield as it is the case for some of the other coalfields of India like Jharia coalfield. Earlier efforts were made to map the coal fires of this coal-field based on satellite observation. But the restricted distribution of major coal fires in the particular portion of the coalfield makes the basis for finding the geological control if responsible for coal fire distribution. In present study, night time thermal data of ASTER (Advance spaceborne thermal emission and reflection radiometer) is used to map the latest distribution (December, 2006) of coal fires in the Raniganj coalfield. Coal fire map shows that most significant zone affected by fire is at the north-western portion of the coalfield; where NE- trending open cast mines are affected by fire. This fire zone is associated with high grade coal of the Barakar Formation. Coal fires are also mapped in open cast pits of Jambad-Mangalpur area occurring over rocks of the Raniganj Formation. By integrating geological map and satellite-derived coal fire map of Raniganj coal field, it is observed that the coal fires detected by remote sensing study are spatially associated with intraformational faults. These faults may have played significant role in supplying oxygen to these coal-fires and allowing them to propagate down the depth along the trends of the faults.

Keywords

ASTER, Coal Fire, Intraformational Faults, Thermal Channels, West Bengal.

Full Text

     

Arindam Guha ¹, Debashish Chakraborty ², A. B. Ekka ², Kaushik Pramanik ², K. Vinod Kumar ¹, S. Chatterjee ², S. Subramanium ¹, D. Ananth Rao ¹

Affiliations
1 National Remote Sensing Centre, Balanagar, Hyderabad - 500 037, IN
2 Geological Survey of India, Jawaharlal Nehru Road, Kolkata - 700 016, IN

Abstract

Recent developments in sensor technology have given an onset for studying the earth surface features based on the detailed spectroscopic observation of different rocks and minerals. The spectroscopic profiles of the rocks are always quite different than their constituent minerals however, the spectral profile of a rock can be broadly reconstituted from the spectral profile of each constituent minerals. Interpretation of rock spectra using the spectra of constituent minerals based on relative spectral matching can bring out interesting information on the rock. Present study is an effort toward this and it highlights how visible-near infrared-shortwave-infrared (VNIR-SWIR) rock spectroscopy acts as an useful tool for understanding the rock-mineralogy in indirect and rapid way. It has also been observed that spectral signatures of rocks; studied in present case, are related to spectral signatures of constituent minerals although absorption features of constituent mineral in the rock are also modified by the other minerals juxtaposed in the rock fabric. However, each rock of the study area has their significant absorption features, but many of the absorption signatures are closely spaced, as altered rock has significant absorption at 2305 nm whereas amphibolite has its important absorption signature in 2385 nm and metabasalt has its significant absorption at 2342 nm. Therefore spectral measurement of high spectral resolution with appreciable signal to noise ratio (SNR) only can detect rocks from each other based on the absorption signatures mentioned above (each of which is 10 to 20 nm apart from the other) and therefore spectroscopy of rock is an innovative technique to map rocks and minerals based on the spectral signatures.

Keywords

Rock Fabric, Spectroscopy, Spectral Matching, Spectral Resolution.

Full Text