Ajit Kumar Saha received DPhil (1958) from University of Calcutta and PhD (1958) from University of Toronto, Canada. He worked as Professor of Geology (1962-90), Head, Department of Geology (1978-85), and later CSIR Emeritus Scientist (1990-93) at Presidency College, Kolkata.
Academic and Research Achievements: Working in the areas: petrology, geochemistry, precambrian geology and environmental geology, Saha deciphered the Precambrian crustal evolution of the Singhbhum ¬¬ (north Orissa region), discovering 3.7 Ga relics (the oldest known so far in India); pioneered in India the application of statistical techniques to understand the processes involved in genesis of granitic rocks and ore deposits; and also pioneered multi-disciplinary research on the environmental problems of eastern India. Saha and his school demonstrated that the Singhbhum Granite is a composite batholith made up of 12 different plutons, each with its distinctive structural pattern and petrological characters. They were emplaced in three different phases. Petrogenetic models were developed for the different groups. Saha’s meticulous work combining field study, petrography and geochemistry will remain a model study for batholiths to the Indian geologists for many years to come. Saha also undertook a study of the geochemistry and magmatectonics of the granite plutons and pegmatite bodies of the Bihar mica belt. He presented a model for the emplacement of the economically important pegmatite bodies and put forward a hypothesis based on the role of fluid pressure during crystallization of pegmatites for the genesis of muscovite books. He indicated several simple geochemical criteria for the exploration of muscovite bearing pegmatites. Thus he was a pioneer in concept oriented exploration of economic minerals. While working on the Singhbhum Granite Professor Saha became interested in the general problem of Precambrian stratigraphy and tectonics of Singhbhum. They (along with SN Sarkar) showed that the Singhbhum terrain is made up of an Archaean nucleus and a Proterozoic belt, and invoked plate tectonic processes for the evolution of the terrain. Four decades of Saha’s sustained work in Singhbhum culminated in the publication of the monograph on Crustal Evolution of Singhbhum-North Orissa, Eastern India, brought out by the Geological Society of India in 1994. He also co-authored two books.
Other Contributions: Professor Saha played a leading role in the development and growth of earth sciences in India. He served as Corresponding Member, International Union of Geological Sciences (IUGS) Subcommission on Precambrian Stratigraphy; and Member, Indian National Committee of IUGS, International Association of Mathematical Geology and the INSA Council (1974-76). He served on various committees of DST, CSIR, UGC, GSI, etc. He edited one book and was Editor of the Journal of the Geological Mining & Metallurgical Society of India (1966-72), and Indian Journal of Earth Sciences (1987). He was also Member of the Editorial boards of Computer Geoscience and Mathematical Geology (1980-91).
Awards and Honours: Professor Saha was conferred the National Mineral Award (1969); UGC National Lecturership (1970); and Hemchandra Dasgupta Memorial Lectureship of the Geological, Mining & Metallurgical Society of India (1986). He was elected Chairman of the Indian Society of Earth Sciences; Fellow, Indian Academy of Sciences, Bangalore, and Geological, Mining & Metallurgical Society of India; Life Fellow, Geological Society of India; and Honorary Secretary, Centre for Study of Man and Environment (1978).