ISL-amenable sandstone-type uranium deposit: Global aspects and recent developments in China

ISL-amenable sandstone-type uranium deposit: Global aspects and recent developments in China

a East China Institute of Technology, Jiangxi Province, China. b Beijing Research Institute of Uranium Geology, Chaoyang District, Beijing, China. c Changsha Uranium Geology Research Institute, China

Abstract

It is concluded that most of known ISL-amenable uranium deposits are attributed to roll sub-type, a minority to basal-channel sub-type, and a few to tabular in case that redistribution of U occurred. Such a classification and related explanation are beneficial to exploration in China. However, there exist significant differences between deposits in Central Asia and those in Wyoming in aspects of tectonic background, scale and shape of host sandbodies, and attitude of ore bodies though all are attributed to the same roll sub-type. Similar situation is presented for deposits of basal channel sub-type. So, it is proposed to establish deposit model and  odel series, providing guidelines for exploration. Four model series and eleven models have been tentatively formulated, including: 1) Central Asia-South Texas series (Chu Sarysu-Syr Darya, Central Kyzylkum, Yili and  outh Texas models) where hosts are large-scale tabular sandbodies, usually developed on the slope parallel to the long axis of the basin and orebodies have a “C” shape with convex surfaces perpendicular to the long axis of the basin; 2) Wyoming series (Shirley-Wind River-Powder River and Great Divide models) where hosts are moderate/small sandbodies forming a wide ribbon, deposited in compressive foreland basins while ore bodies  occur on both margins of ribbon-shaped sandbodies with the convex surfaces directed outwards; 3) Grants series (Grants-primary and Grants re-distributed models) where host sandstones were deposited as channel fill within a large-scale humid alluvial fan, containing plenty of organic matter, and orebodies are mostly tabular in shape, transformed locally into roll form; and 4) Siberia-Bohemia series (West Siberia, Trans-baikal-West Yunnan and  North Bohemia models) where U concentrations occur in, on, and/or adjacent to detrital plant debris within the channel sandstone, filling incised valley. Besides, recognition criteria are briefly explained. On the other hand, the sandstone-type uranium metallogenetic prospect of China is discussed with special attention to the Northwest Territory of China that could be considered as the east extension of a giant uranium super-province, stretching from Central Asia eastwards. The territory includes four domains and thirteen sub-domains different in uranium endowment. Meanwhile, the features of six selected deposits/mineralized areas are described in brief, including  the Kujie’ertai, roll sub-type, hosted in tabular sand-bodies (J1-2sh); the Shihongtan, roll sub-type, hosted in ribbon-shaped sand-bodies (J2x); the Dongsheng, tabular sub-type with local U redistribution, hosted in ribbon-shaped sand-bodies (J2z); the Nuheting, tabular sub-type, hosted in ribbon-shaped sand-bodies (K2e); the Bayantala, basal channel sub-type of Mesozoic (K1bs) age; and the Chenzishan, basal channel sub-type of Cenozoic (N2m age). Finally, it is emphasized that China, especially the Northwest Territory of China, remains highly perspective, having only minor exploration in the past.