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Gain and loss of uranium by meteorites and rocks, and implications for the redistribution of uranium on Mars
Author(s) -
DREIBUS Gerlind,
HAUBOLD Reinhard,
HUISL Wolfgang,
SPETTEL Bernhard
Publication year - 2007
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2007.tb01143.x
Subject(s) - meteorite , uranium , martian , mars exploration program , basalt , dissolution , adsorption , martian surface , geology , mineralogy , chemistry , martian soil , astrobiology , geochemistry , materials science , metallurgy , physics , organic chemistry
Terrestrial 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.