Sushina hills are situated in the Purulia-Bankura Shear Zone. This is tectonically disturbed narrow zone nearly 100 Km long having WNW-ESE trend. Two different rock assemblages namely Chhotanagpur Gneissic Complex and rocks of Singhbhum Group occur on the two sides of this shear zone. In this paper, I have used fission track ages of two cogenetic minerals and their corresponding closure temperatures to describe the denudation history. The difference of their fission track ages provides the rate of denudation 4 m/Ma during the period 970Ma-1458Ma due to tectonic activity. The youngest age of zircon of 970Ma represents the timing of the initiation of denudation.
Apatite fission-track (AFT) analysis has been widely used to constrain the low-temperature thermal histories of many igneous, metamorphic and sedimentary rocks in a wide range of geological settings. This study is one of very few studies which have investigated the rate of denudation 4m/Ma and the timing of the initiation of denudation.
This study received no specific financial support.
The author declares that there are no conflicts of interests regarding the publication of this paper.
I am thankful to Prof. Richard Ketcham “University of Texas”, U.S.A., Prof. Barry Paul Kohn, “University of Melbourne”, Australia, and Dr. Subhajit Saha, Post Doctoral Research Fellow, IIT Kharagpur. I am highly indebted to the Director General of Geological Survey of India, 27, J.L. Nehru Road, Kolkata – 700 016, for his kind permission to perform my work in the laboratory of G.S.I, Kolkata. I thank the entire team of FRMII, Garching, Germany for providing me with use of the irradiation facility, free of charge.