Gain and loss of uranium by meteorites and rocks, and implications for the redistribution of uranium on Mars
MetadataShow full item record
CitationDreibus, G., Haubold, R., Huisl, W., & Spettel, B. (2007). Gain and loss of uranium by meteorites and rocks, and implications for the redistribution of uranium on Mars. Meteoritics & Planetary Science, 42(6), 951-962.
PublisherThe Meteoritical Society
JournalMeteoritics & Planetary Science
AbstractTerrestrial alteration of meteorites results in the redistribution, gain, or loss of uranium and other elements. We have measured the maximum U adsorption capacity of a meteorite and two geochemical reference materials under conditions resembling terrestrial ones (pH 5.8). The basaltic eucrite Sioux County adsorbs 7 ppm of U. The result for the terrestrial granite AC-E is similar (5 ppm), while the basalt BE-N adsorbs 34 ppm of U. We have also investigated U adsorption in the presence of phosphate (0.01 M or less) in imitation of conditions that probably occurred in the earlier history of Mars. Such a process would have alterated Martian surface material and would be noticeable in Martian meteorites from the affected surface. The experiments demonstrated the counteracting effects of phosphate, which increases U adsorption, but decreases the quantity of dissolved U that is available for adsorption. U adsorption by AC-E increases to 7 ppm. The lowered value for BE-N of 8 ppm results from the low quantity of dissolved U in the volume of solution used. The results from the adsorption experiments and from leaching the Martian meteorite Zagami and a terrestrial basalt imply that the aqueous redistribution of U on Mars was moderate. Acidic liquids mobilized uranium and other metals, but present phosphate impeded the dissolution of U compounds. Some mobilized U may have reached the global sinks, while most of it probably was transported in the form of suspended particles over a limited distance and then settled.