Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The gamma‐ray activities of 33 meteorite samples (30 ordinary chondrites, 1 Mars meteorite, 1 iron, 1 howardite) collected during Omani‐Swiss meteorite search campaigns 2001–2008 were nondestructively measured using an ultralow background gamma‐ray detector. The results provide several types of information: Potassium and thorium concentrations were found to range within typical values for the meteorite types. Similar mean <jats:sup>26</jats:sup>Al activities in groups of ordinary chondrites with (1) weathering degrees W0‐1 and low <jats:sup>14</jats:sup>C terrestrial age and (2) weathering degree W3‐4 and high <jats:sup>14</jats:sup>C terrestrial age are mostly consistent with activities observed in recent falls. The older group shows no significant depletion in <jats:sup>26</jats:sup>Al. Among the least weathered samples, one meteorite (SaU 424) was found to contain detectable <jats:sup>22</jats:sup>Na identifying it as a recent fall close to the year 2000. Based on an estimate of the surface area searched, the corresponding fall rate is ~120 events/10<jats:sup>6</jats:sup> km<jats:sup>2</jats:sup>*a, consistent with other estimations. Twelve samples from the large JaH 091 strewn field (total mass ~4.5 t) show significant variations of <jats:sup>26</jats:sup>Al activities, including the highest values measured, consistent with a meteoroid radius of ~115 cm. Activities of <jats:sup>238</jats:sup>U daughter elements demonstrate terrestrial contamination with <jats:sup>226</jats:sup>Ra and possible loss of <jats:sup>222</jats:sup>Rn. Recent contamination with small amounts of <jats:sup>137</jats:sup>Cs is ubiquitous. We conclude that gamma‐ray spectroscopy of a selection of meteorites with low degrees of weathering is particularly useful to detect recent falls among meteorites collected in hot deserts.</jats:p>