PhD in Remote Sensing and Earth Science
Msc. Tech in Applied Geology
RESEARCH INTERESTS
Mineral exploration, Remote Sensing, Geographical Information System, Structural Mapping, Lithology Mapping, Alteration study and their applications. Hydrothermal alteration mapping using Remote Sensing, GIS and Field study and their application for Mineral Exploration.
Remote geochemical alteration proxy for mineral exploration: A case study from Lawa gold mines, India Pankajini Mahanta, Sabyasachi Maiti Journal of Asian Earth Sciences X, 2022 Geochemical alteration indexes viz. carbonate chlorite pyrite index, ishikawa alteration index, hashiguchi alteration index, chemical alteration index and silicification index are conventionally used to study the degree and type of alteration. Thin section microscopic and X-ray Fluorescence analysis got similar roles for alteration study. Due to sparse and expensive sampling, the regional depiction of alteration patterns and their quantitative analysis are usually unavailable for exploration geologists. Here, we provided an alternative remote proxy-based approach to map the degree and type of alteration on a large scale, using visible-near infrared and shortwave infrared bundles of WorldView-3 imagery. The chosen study area is sparsely vegetated Lawa gold deposit in the North Singhbhum Mobile Belt, India. Partial least squares regression (PLSR) modelling of geochemical alteration indexes with reflectance spectra was used to understand the spatial variation in the degree of alterations. The remotely derived alteration indexes can be linked with field and microscopic studies of Cu-Au mineralization. We found dominance of alteration processes in the following order: ferruginisation, silicification, sericitization and chloritization. Demarcated intensely hydrothermally altered zones are present near the exposed mineralized outcrop. In addition, we identified new alteration zones with ore phases as a plausible mineralized zone.
Identification and mapping of high-potential iron ore alteration zone across Joda, Odisha using ASTER and EO-1 hyperion data Arnab Sengupta, Manik Das Adhikari, Sabyasachi Maiti, Soumya Kanti Maiti, Pankajini Mahanta, Siddhartha Bhaumick Journal of Spatial Science, 2019 Identification and mapping of high-potential Iron Ore indicative alteration zone is important for new prospects. Here we have performed same through ASTER and Hyperion data by considering the in-situ and reported spectral signatures and Band Ratio techniques. The Minimum Noise Fraction and Pixel Purity Index have been applied for the noise reduction and pure pixel extraction from the Hyperion data. Spectral Angle Mapper algorithm has been used to identify the Hematite and Goethite exposures based on the spectral assembling. On the other hand, Ferric Iron, Ferrous Iron, Ferrous Silicates, and Ferric Oxide index have been applied on ASTER VNIR and SWIR data for demarcating alteration zones indicating subsurface occurrence of iron ore. Thereafter, the consistency index has been established between the ground truth/field observations and classified alteration through kappa statistics demonstrates the accurate identification and remote mapping of Iron Ore alteration zone in and around Joda region.
