Dr Anirban Basu

Dr Anirban Basu

Lecturer in Earth Sciences

Phone: +44 1784 414083

Personal profile

I received my PhD from the University of Illinois, Urbana-Champaign in 2013 before joining the Center for Isotope Geochemistry at University of California, Berkeley. I was a postdoc at UC Berkeley and Lawrence Berkeley National Lab from 2013 to 2016. 

 

Research: My area of interest is low-temperature geochemistry, particularly the use of non-traditional stable isotope systems as indicators of biogeochemical processes in modern and ancient environments. Biologically mediated reduction-oxidation (redox) reactions are critical to many aspects of chemistry involved in energy and environment. Changes in the isotopic ratios of the key metal elements typically accompany reduction reactions. Several redox-sensitive elements (e.g., Cr, U, Se, and Mo) show great promise as indicators of reductive remediation of dissolved contaminants (e.g., Cr(VI) or U(VI)), and help place constraints on past ocean or atmospheric chemistry as well as the formation of economic ore deposits (e.g., roll-front U ore).

 

My current research focuses on detection and efficient monitoring of U(VI) reduction at the in situ recovery (ISR) U mining of roll-front U deposits. ISR U mining operations account for ~50% of the global U mining but leave soluble U(VI) in the groundwater that must be restored below the existing regulatory limit to minimize the environmental impact of mining. The undisturbed and chemically reduced sediments may reduce U(VI) to less toxic and insoluble U(IV) and promote natural attenuation. I use multiple redox active isotope proxies such as U (238U/235U and 234U/238U), Se, Mo, S, N, and O isotope ratios to trace U mobility and detect naturally occurring reducing environments conducive to remediation of U(VI) at an ISR mining sites 

 

I am also investigating how the redox-interface, responsible for low temperature U ore formation, extends along the hydraulic gradient, both vertically and horizontally, and gives rise to isotopic heterogeneity. We are carrying out a detailed isotopic characterization of a roll-front U deposit to determine the natural variability of δ238U, δ82Se, δ98Mo, δ34S and 234U/238U activity ratio of the U ore. This characterization work will provide the much needed background isotopic signature for groundwater within the ore zone and serve as a foundation for future detection and quantification of post-mining U(VI) or Se-oxyanion remediation. This will help generate a well-constrained geochemical model of formation and evolution of redox interfaces.

 

Microbial isotopic fractionation of several elements (e.g., Cr, U, Se, Mo) has been employed to understand biological activity, origin and evolution of life in the early Earth. The exact mechanisms and geochemical factors influencing the magnitude of isotopic fractionation during microbial cycling of elements not yet well understood. My research aims to develop a model to better understand the overall isotopic fractionation expressed in relation to the subcellular localization of metal (e.g., U(VI)) reduction. This will provide a mechanistic understanding of the isotopic fractionation during microbial metal cycling and will form the basis for advanced reactive transport models. 

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