Surface and core samples of Neh–nar Glacier in the Kashmir Valley have been analysed for the radionuclides 32Si. 210Pb, 40K, and 137Cs. The lateral and vertical profiles (at an altitude of about 4 140 m) reveal:(1)32Si activity decreasing slowly from the accumulation zone to 4 050 m altitude and then abruptly towards the snout.(2)Five zones of alternating high and low 210Pb activity in the surface samples.(3)An horizon at between 2 and 3 m depth containing 210Pb activity above natural levels. This horizon is also associated with 137Cs and a maximum in total ß activity.The ice samples have been dated on the basis of a simplified two–component model, the “fresh“contribution determined by 2l0Pb and the old component by 32Si. The following conclusions can be drawn from these observations:(1)The model age of the snout ice is c. 850 years.(2)The average rate of ice movement in the lower glacier is about 2 m/year, which compares well with the annual movement rate of 2.65 m/year observed since 1974.

The concentration of radioisotopes rBe, ~S were measured in Bombay since 1956 and ~2Na, ~a~ z~Si since 1963. In Khandala and other stations such measurements have been made at irregular periods since 1961. In addition several measurements especially that of 32Si were made in 1970. Data available todate from Indian stations is summarised and critically analysed. We conclude that appreciable amounts of ~S, 2~Na and 8JSi, over and above their production by cosmic rays, were produced during the high yield Russian tests as evidenced by their fallout between 1962-66. Based on the bomb produced excess the half period for their removal from the stratosphere is deduced to be less than 1 year. The ' excess' contribution of 3aSi due to bombs is, however, small; about 1~0 of its inventory in the oceans. The present study shows that for stations where orogeny is the principal mer nism of precipitation, the annual fallout is independent of the annual rainfall.

Systematic isotopic studies based on natural and artificial radio-isotopes (32Si, 137Cs), stable isotopes (δ18O) and total β activity measurements have been carried out on Chhota Shigri glacier, Himachal Pradesh, central Himalaya, to study the dynamics of the ice, meltwater composition and to identify the deposition of the Chernobyl fall-out in the Himalayan region.Using 32Si concentrations, the snout ice has been dated at ~ 250 years, based on which the past average surface ice-flow rate has been estimated as ~ 28 m year−1. Based on δ18O variations, in a shallow ice core, the accumulation rate of the ice has been estimated at ~520kgm−2 year−1. 32Si measurements of snout ice and englacial meltwaters indicate that at least 55% of the snow meltwater mixed with 45% of the old ice-melt water that emerged from englacial streams in the month of August 1987. Deposition of the artificial radionuclide (137Cs) and the very high total β activity observed in snow samples on Chhota Shigri glacier give the first evidence of Chernobyl fall-out deposition in the Indian Himalaya.

Systematic isotopic studies based on natural and artificial radio-isotopes (32Si,137Cs), stable isotopes (δ18O) and total β activity measurements have been carried out on Chhota Shigri glacier, Himachal Pradesh, central Himalaya, to study the dynamics of the ice, meltwater composition and to identify the deposition of the Chernobyl fall-out in the Himalayan region.Using32Si concentrations, the snout ice has been dated at ~ 250 years, based on which the past average surface ice-flow rate has been estimated as ~ 28 m year−1. Based on δ18O variations, in a shallow ice core, the accumulation rate of the ice has been estimated at ~520kgm−2year−1.32Si measurements of snout ice and englacial meltwaters indicate that at least 55% of the snow meltwater mixed with 45% of the old ice-melt water that emerged from englacial streams in the month of August 1987. Deposition of the artificial radionuclide (137Cs) and the very high total β activity observed in snow samples on Chhota Shigri glacier give the first evidence of Chernobyl fall-out deposition in the Indian Himalaya.

δ18O in ice cores taken from two temperate glaciers, Changme‐Khangpu (CK) and Nehnar. located in the eastern and the western Himalayas respectively, and in fresh precipitation and surface ice at different altitudes on the Changme‐Khangpu glacier has been measured. The fresh precipitation in CK has δ18O in the narrow range of −19 ± 2‰ which is similar to the ice core values. δ18O and dust concentration in Nehnar core is found to be variable. The δ18O values lie in the narrow range of −9.5 ± 1‰ in the upper 46 m section and the fluctuations increase in the 66–102 m section of the ice core.

Surface and core samples of Neh–nar Glacier in the Kashmir Valley have been analysed for the radionuclides 32Si. 210Pb, 40K, and 137Cs. The lateral and vertical profiles (at an altitude of about 4 140 m) reveal: (1)32Si activity decreasing slowly from the accumulation zone to 4 050 m altitude and then abruptly towards the snout. (2)Five zones of alternating high and low 210Pb activity in the surface samples. (3)An horizon at between 2 and 3 m depth containing 210Pb activity above natural levels. This horizon is also associated with 137Cs and a maximum in total ß activity. The ice samples have been dated on the basis of a simplified two–component model, the “fresh“contribution determined by 2l0Pb and the old component by 32Si. The following conclusions can be drawn from these observations: (1)The model age of the snout ice is c. 850 years. (2)The average rate of ice movement in the lower glacier is about 2 m/year, which compares well with the annual movement rate of 2.65 m/year observed since 1974.

Measurements of natural and artificial radioisotopes (32Si, 210Pb and 137Cs) and oxygen isotopes (δ18O) have been carried out on surface snow and ice, shallow snow pits and an ice core collected from Dokriani Bamak glacier, central Himalaya, to study the dynamics of glacier ice and short-term climatic changes. Based on the 32Si and 210Pb activities in the meltwaters, the age of the snout ice is 400 years and the flow rate of ice along the glacier length is ∼14 m a−1. The specific activity of 137Cs, corresponding to 1963 fallout, in the surface ice at the equilibrium line yields a flow rate of 32 m a−1, a factor of two higher than that derived for the snout ice. The depth variation of 137Cs concentration in a shallow ice core yields a mean accumulation rate of 0.43 m a−1 for the glacier ice over the past decade. The δ18O of snout ice (−13.4‰) is significantly depleted compared to the average value of −9.2‰ in the shallow ice core, indicating that cooler climatic conditions prevailed around AD 1600. Based on the oxygen isotopic ratios in the shallow pits, an “altitude effect” of 0.9‰ per 100 m in δ18O variation is documented for this glacier.

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