Applications of cosmogenic radionuclides (CRN) ¹⁰Be and ²⁶AI in earth system sciences: from Indian prospective

CRNs (¹⁰Be and ²⁶AI) are being used for understanding various earth surface processes. The production rates of these nuclides are very low in the Earth's environment. However the advancement in the measurement techniques and apposite half life for dating various surfacial processes has helped earth scientists to use these nuclides as geochronometer and tracer. Most importantly to establish an absolute time scale for the geological and paleoclimatic events of the quaternary period. During quaternary period earth witnessed major modification in the landforms and climatic upheavals. Accelerator Mass Spectrometry (AMS) technique provided ample scope to apply CRN as a proxy to decipher temporal and spatial variation of earth surface processes. This technique has been widely applied for studying exposure ages, erosion rates and burial history etc. despite of some associated limitations and uncertainties. However in India application of CRN technique is limited. One of the important hindrances was the availability of AMS facility for measurement of CRNs. Here an attempt has been made to identify the possible limitations (other than the AMS facility) which restrict the use of CRNs (in situ ¹⁰Be, ²⁶AI) in India. From literatures, it is evident that CRN dating method is successfully being applied in the Himalaya for understanding palaeo-glacier advance and retreat during quaternary period. Production rate of in situ CRNs is controlled by latitude and altitude therefore Himalayan region provided better prospect to apply this technique compare to peninsular region. Nevertheless this technique can be applied in the peninsular region efficiently with the help of establishing production rate for Indian subcontinents, calibrating different shielding factors and with the help of a supporting age by another method. The detail methods will be discussed during presentation. (author)