Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The common appearance of hygroscopic brine (“sweating”) on ordinary chondrites (<jats:styled-content style="fixed-case">OC</jats:styled-content>s) from <jats:styled-content style="fixed-case">O</jats:styled-content>man during storage under room conditions initiated a study on the role of water‐soluble salts on the weathering of <jats:styled-content style="fixed-case">OC</jats:styled-content>s. Analyses of leachates from <jats:styled-content style="fixed-case">OC</jats:styled-content>s and soils, combined with petrography of alteration features and a 11‐month record of in situ meteorite and soil temperatures, are used to evaluate the role of salts in <jats:styled-content style="fixed-case">OC</jats:styled-content> weathering. Main soluble ions in soils are <jats:styled-content style="fixed-case">C</jats:styled-content>a<jats:sup>2+</jats:sup>, <jats:styled-content style="fixed-case">SO</jats:styled-content><jats:sub>4</jats:sub><jats:sup>2−</jats:sup>, <jats:styled-content style="fixed-case">HCO</jats:styled-content><jats:sub>3</jats:sub><jats:sup>−</jats:sup>, <jats:styled-content style="fixed-case">N</jats:styled-content>a<jats:sup>+</jats:sup>, and <jats:styled-content style="fixed-case">Cl</jats:styled-content><jats:sup>−</jats:sup>, while <jats:styled-content style="fixed-case">OC</jats:styled-content> leachates are dominated by <jats:styled-content style="fixed-case">M</jats:styled-content>g<jats:sup>2+</jats:sup> (from meteoritic olivine), <jats:styled-content style="fixed-case">C</jats:styled-content>a<jats:sup>2+</jats:sup> (from soil), <jats:styled-content style="fixed-case">C</jats:styled-content>l<jats:sup>−</jats:sup> (from soil), <jats:styled-content style="fixed-case">S</jats:styled-content>O<jats:sub>4</jats:sub><jats:sup>2−</jats:sup> (from meteoritic troilite and soil), and iron (meteoritic). “Sweating meteorites” mainly contain <jats:styled-content style="fixed-case">M</jats:styled-content>g<jats:sup>2+</jats:sup> and <jats:styled-content style="fixed-case">C</jats:styled-content>l<jats:sup>−</jats:sup>. The median <jats:styled-content style="fixed-case">N</jats:styled-content>a/<jats:styled-content style="fixed-case">C</jats:styled-content>l mass ratio of leachates changes from 0.65 in soils to 0.07 in meteorites, indicating the precipitation of a <jats:styled-content style="fixed-case">N</jats:styled-content>a‐rich phase or loss of an efflorescent <jats:styled-content style="fixed-case">N</jats:styled-content>a‐salt. The total concentrations of water‐soluble ions in bulk <jats:styled-content style="fixed-case">OC</jats:styled-content>s ranges from 600 to 9000 μg g<jats:sup>−1</jats:sup> (median 2500 μg g<jats:sup>−1</jats:sup>) as compared to 187–14140 μg g<jats:sup>−1</jats:sup> in soils (median 1148 μg g<jats:sup>−1</jats:sup>). Soil salts dissolved by rain water are soaked up by meteorites by capillary forces. Daily heating (up to 66.3 °C) and cooling of the meteorites cause a pumping effect, resulting in a strong concentration of soluble ions in meteorites over time. The concentrations of water‐soluble ions in meteorites, which are complex mixtures of ions from the soil and from oxidation and hydrolysis of meteoritic material, depend on the degree of weathering and are highest at W3. Input of soil contaminants generally dominates over the ions mobilized from meteorites. Silicate hydrolysis preferentially affects olivine and is enhanced by sulfide oxidation, producing local acidic conditions as evidenced by jarosite. Plagioclase weathering is negligible. After completion of troilite oxidation, the rate of chemical weathering slows down with continuing <jats:styled-content style="fixed-case">C</jats:styled-content>a‐sulfate contamination.</jats:p>