Uranium in icy Ladakh

Scientists have for the first time found uranium in “exceptionally high concentration” in Ladakh.

Scientists have for the first time found uranium in “exceptionally high concentration” in Ladakh, the icy Himalayan region in Jammu and Kashmir that has strategic significance for India.

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Samples of rocks analysed in a German laboratory have revealed uranium content to be as high as 5.36 per cent compared to around 0.1 per cent or less in ores present elsewhere in the country.

India badly needs uranium to fuel its nuclear power plants and the proposed India-US nuclear deal is all about importing it. The Ladakh find may cheer those opposed to the deal even though detailed exploration and mining may take years.

The Ladakh block lies between the Indian plate in the south and the Asian plate in the north and is bounded by the “Indus and the Shyok suture zones”. Collision between the two plates 50-60 million years ago formed the Himalayas.

The earth’s crust that got crushed and melted during collision and pierced the surface, cooled and solidified becoming “magmatic” rocks dotting what geologists call the Ladakh “batholith”. It is in these rocks that uranium is found.

“The presently recorded uranium rich zircons from young magmatic intrusions of the Shyok suture zone and associated sequences is the first record from these remote regions,” said Rajeev Upadhyay, a geologist at Kumaon University in Nainital.

“In geological terms, these uranium-bearing magmatic rocks exposed in Ladakh are very young (between 100 million and 25 million years old),” he said.

Other uranium rich rocks in India such as in Andhra Pradesh, Chhattisgarh, Jharkhand and Rajasthan are very old geological terrains known as the Precambrian (2,500-3,000 million years old), he said.

For his study, reported in the journal Current Science, Upadhyay took samples from thick exposed granite from a place north of Udmaru village in Leh district. The village in the Nubra-Shyok River Valley is situated on a volcanic rock formation known as the Shyok Volcanics.

The samples of rock mineral (zircon) were analysed at the isotope laboratory of the University of Tuebingen in Germany where he had gone under the Alexander von Humboldt Fellowship.

“Geochemical analysis of the separated zircon grains showed exceptionally high concentration of both uranium (0.31 - 5.36 per cent) and thorium (0.76 - 1.43 per cent),” said Upadhyay. He added that the study is preliminary and “detailed work is in progress”. According to Upadhyay, uranium-bearing magmatic rocks are located all along Kohistan, Ladakh and southern Tibet (from east to west). “However, contents of uranium may differ from place to place,” he said.

Officials of the atomic minerals division under the Department of Atomic Energy (DAE) did not reply to questions about the significance of this new find or whether the Ladakh uranium could augment India’s reserves.

The total established uranium resources of the country so far (in the form of uranium oxide or yellow cake) are 94,000 tonnes. The majority of these resources, according to DAE, occur in three “provinces”: Singhbhum in the east, Mahadek in the northeast and Cuddapah in the south.

The low uranium content in ores, however, makes mined uranium in India expensive compared to that in Australia whose ores contain as much as 15 per cent uranium.