Mineralogical characteristics of low-rank coal from Nagaur, Rajasthan, India and their implication for the environment of paleomire

ABSTRACT

In the present investigation, lignite samples from working seams of Matasukh mines, Nagaur, Rajasthan have been subjected to optical microscopy and mineralogy to determine their mineralogical characteristics and paleodepositional condition. Petrographic analysis of composite samples indicates that these lignites are dominated by carbonate minerals followed by sulfides and clay minerals. Framboidal pyrites have also been recorded in the Nagaur lignite samples, which reveals marine incursion into the study area. The occurrence of clay mineral in cell cavities, fissure, and cracks indicates authigenic and syn-depositional origin of the Nagaur lignite. The study reveals Nagaur lignites deposited under terrestrial oxic to marine terrestrial oxic to sub-oxic condition and semi-arid to slightly arid paleoclimatic conditions.

KEYWORDS:

• Mineralogy
• Environment
• XRD
• XRF
• FT-IR

Acknowledgments

We are thankful to the Director, RGIPT, Jais, Amethi, India, for providing all the facilities. The financial support received from the Department of Science & Technology (Project No. SB/S4/ES-681/2013), Government of India thankfully acknowledged by authors.

Additional information

Funding

This work was supported by the Department of Science & Technology [Project No. SB/S4/ES-681/2013].

Notes on contributors

Alok K. Singh

Dr. Alok K. Singh received his Ph.D. and MSc in Geology from the Banaras Hindu University, India. He is an Associate Professor at the Department of Petroleum Engineering and Geosciences, Rajiv Gandhi Institute of Petroleum Technology Jais, Amethi, India. His research interests include coal and organic petrology, organic maturation and thermal history, oil and gas generation, sedimentology, coal beneficiation, and petroleum geology. He is the author and co-author more than 50 publications including book chapters and has given more than 20 lectures and seminars, workshops and short courses throughout the world.

Alok Kumar

Alok Kumar receives his master degree in Applied Geology from IIT, Indian School of Mines, Dhanbad, India. He is currently working as a senior research fellow at the Department of Petroleum Engineering and Geosciences, Rajiv Gandhi Institute of Petroleum Technology Jais, Amethi, India. His research interests include petrography of organic-rich sediments (i.e. coal, lignite, and shale), rank and maturity of organic matter, hydrocarbon potential of organic matter and their paleodepositional environment. He has ten publications to his credit.

Jayant Kumar Tripathi

Jayant Kumar Tripathi work in the field of Sedimentary Geochemistry and Geochemistry of Earth Surface Processes. He is a recipient of National Geoscience Award of India in 2009. He has published many papers in research areas of river processes, desert processes, chemical weathering of rocks, sedimentary geochemistry of old rocks, and paleoclimatology.