Tandon is known to have done extensive researches on sedimentary tectonics and magnetostratigraphy and his work on the Siwalik rocks is reported to have assisted in the wider understanding of this tectonically dynamic region of the Himalayas. He pioneered the physical dating techniques such as magnetic polarity, luminescence dating, fission track dating of zircons in India and he contributed to reconstruct the Late Cretaceous palaeogeography of Central India which revealed the impact of Deccan volcanism on contemporary sedimentary environments. His studies have been detailed in several peer reviewed articles; ResearchGate and Google Scholar, two online repositories of scientific articles has listed 110 and 180 of them respectively. He sat in several government agencies as a member. He was a member of the project advisory committees of the Department of Science and Technology (1994-97), Council of Scientific and Industrial Research (2001-05), Integrated Long-Term Program (2001-04) and Central Groundwater Board (2001-04) and chaired the Project Advisory Committee of the DST during 1998-2000. He also chaired the Research Advisory Committees of Wadia Institute of Himalayan Geology (2004-07) and Young Scientists Fast Track Scheme (Earth Sciences) of DST (2005-08) besides being associated with several other councils and committees as a member. He presided the Indian Association of Sedimentologists (2003-12), and served as the vice president of the Geological Society of India during 2007-10 and 2010-13. He was a councillor of International Union of Geological Sciences (IUGS) during 2010-14 and has been serving as the vice president of the Indian Mineralogists Association since 2005. He was the convenor of the editorial committee of the University Grants Commission of India for promoting research at educational institutions in 2004 and was a member of the editorial board of Current Science (2003-13) and the Proceedings in Earth and Planetary Sciences of the Indian Academy of Sciences. He is the incumbent chairman of the research advisory council of Birbal Sahni Institute of Palaeobotany and a member of the advisory committee of the Indian Statistical Institute.