Wednesday, March 19, 2008

How to make Uranium from wood

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Yes! You read the title correctly! Today I found an article in Ore Geology Reviews from M.-Z. Min et al. that I find fascinating. Why? It dates from 2001 but it demonstrate how wood is being replaced by uranium minerals! Pitchblende and coffinite to be exact. To some of the old geos around this may be yesterday's news but I am truly amazed. I'm not an expert on this so here is the abstract:
A fossil wood cell texture with pitchblende and coffinite found at a sandstone-hosted roll-type uranium deposit, Xinjiang, NW China, is first reported here for the country. In the mineralized sandstone, detrital grains consisting of quartz, feldspar, rock fragments, carbonaceous trashes, mica and accessory minerals were deposited in early Turassic time and were cemented by clays and minor authigenic calcite and quartz. Pitchblende and minor coffinite are principal ore minerals at the deposit, and selectively replaced carbonized fossil wood remnants or filled fossil wood cells. An excellent fossil wood cell texture with primary uranium minerals formed. Replacement of organic debris by primary uranium minerals may be due to a local reducing environment resulting from the production of CH4, H2S or H2SO3 in its decomposition, and a biochemical reaction indicated by the common presence of framboidal pyrite. (c) 2001 Elsevier Science B.V. All rights reserved.
And also a nice picture taken from the article of M.-Z. Min et al.



I knew that the presence of organic matter was involved in the formation of sandstone hosted roll-type deposits by creating reducing environments but that you can actually get wood replaced by uranium minerals with such great preservation of single cells is totally new and amazing for me. If you are interested I recommend getting a copy of the article!

References:
  • M.-Z. Min, X.-Z. Luo, S.-L. Mao, Z.-Q. Wang, R.C. Wang, L.-F. Qin and X.-L. Tan (2001): An excellent fossil wood cell texture with primary uranium minerals at a sandstone-hosted roll-type uranium deposit, NW China, In: Ore Geology Reviews, Elsevier

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