3D Subsurface Characterization of Banded Iron Formation Mineralization using Large-Scale Gravity Data: A Case Study in Parts of Bharatpur, Dausa and Karauli Districts of Rajasthan, India

• Published in: Natural resources research (New York, N.Y.) Vol. 30; no. 5; pp. 3121 - 3138
• Main Authors: Sahoo, Saudamini, Singh, Anand, Biswas, Santu, Sharma, S. P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2021; Springer Nature B.V
• Subjects: Algorithms; Chemistry and Earth Sciences; Computer Science; Computers; Deconvolution; Earth and Environmental Science; Earth Sciences; Fossil Fuels (incl. Carbon Capture); Geography; Iron; Iron compounds; Iron ores; Mathematical Modeling and Industrial Mathematics; Mineral Resources; Mineralization; Original Paper; Personal computers; Physics; Rocks; Statistics for Engineering; Sustainable Development; Rajasthan India; India; Banded iron formation (BIF); Euler 3D deconvolution; Mineralization; 3D modelling and inversion; Gravity survey; Bhilwara–vindhyan supergroup contact; Delhi supergroup
• ISSN: 1520-7439; 1573-8981
• DOI: 10.1007/s11053-021-09880-y

Our study interprets large-scale gravity data to delineate concealed banded iron formation (BIF) iron mineralization in India's Rajasthan province. The study area belongs to the Bharatpur, Dausa, and Karauli districts of Rajasthan. We measured 1462 gravity readings to understand the rock types, depth and geometry of the different rock formations in the proposed study area. We also collected representative lithologies from more than 100 locations in the study area and calculated their density values. The measured gravity datasets are investigated via qualitative (e.g., Bouguer anomaly, first derivative and second derivative) and quantitative (radially averaged power spectrum, 3D Euler deconvolution, and 3D inversion) approach. The qualitative methods suggest a general NE–SW orientation of the BIFs, controlled by the general trend of the study area's structural setting. The lithological contact between the Bhilwara and Vindhyan Supergroups is demarcated by a NE–SW trending steep gravity gradient zone. In this area, representative lithologies yield high densities (about 3.746 gm/cc), and the samples identified as BIF represent exploration targets for iron ore. We have also developed our own in-house 3D gravity inversion code in this study. A model space inversion algorithm is converted into a data space using the identity relationship. It makes inversion algorithm very user-friendly on conventional desktop computers. The outcomes from the 3D inversion suggest that the concealed iron ore thickens to the west. This interpretation is also in good correlation with Euler 3D deconvolution of the gravity data.