Discussion of the genetic relationship between pyrite and uranium mineralization in Sawafuqi sandstone-type uranium deposits of Tarim basin
Sawafuqi sandstone-type uranium deposit is the main large uranium deposit in the Jurassic of northern Tarim basin,and in the ores presented the close relation of pyrite and uranium minerals.This study focused on the mineral association and microscopic morphological characteristics of the uranium-bearing layers in the sandstone,analyzed the sulfur isotope composition of pyrite to determine its origin and its relation to the uranium mineralization.The results showed that:1)pyrite was closely associated with uraninite,coffinite,and uranium-rich titanium-iron oxide in the ore body,and uranium minerals are mostly found on the edges of pyrite;2)pyrite was commonly found in the form of grains and colloidal particles in the ore body,sulfur isotope values of the pyrite ranged widley from-56.24 ‰ to-11.44％o with an average of-25.79 ‰ indicating its multiple origins;3)the pyrite was coexisted with uraninite,organic matter and clastic minerals which suggest the formation of pyrite was involved with the bacterial reduction and organic matter participation.Therefore the pyrite played a reducing role in uranium mineralization,which resulted in the closely relation of pyrite and uranium minerals in the coal-bearing strata in the study area.
Sawafuqi uranium depositspyritesulfur isotopesandstone type uranium depositsTarim basin
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