Following their fall to Earth, meteorites experience weathering. In this systematic study, we evaluate the trace element composition of ordinary chondrites from the Antarctic cold desert, and Atacama (Chile) and Lut (Iran) hot deserts, with an emphasis on rare earth elements (REE). Our data confirms that terrestrial weathering of meteorites in hot deserts changes their trace element (Sr, Ba, REE, Hf, Th, and U) concentrations. However, weathering effects in majority of Antarctic samples are limited to slight Ba, REE, Hf, and Th depletions and in some case to U enrichment. In comparison to the Antarctic meteorites, hot desert samples show greater disturbances and REE fractionation relative to the average fall values. We measured the Sm-Nd isotopic composition of the hot desert meteorites that have heavily affected REE compositions. Our Sm-Nd isotopic data show a significant effect of terrestrial weathering evidenced by non-CHUR ¹⁴⁷Sm/¹⁴⁴Nd and ¹⁴³Nd/¹⁴⁴Nd ratios. Measurements show a higher variation and lower values of ¹⁴⁷Sm/¹⁴⁴Nd for the Atacama samples than those from the Lut Desert. Deviations from CHUR ¹⁴⁷Sm/¹⁴⁴Nd value are in positive accordance with the degree of La/Lu fractionation caused by weathering. The ɛNd values of Atacama and Lut deserts meteorites range from −2.20 to +1.61, which is wider than the −1.07 to +0.64 range for falls. We suggest that disturbance of primary Sm/Nd ratios resulting from mixing with terrestrial components originating from soil during weathering is responsible for lower ¹⁴⁷Sm/¹⁴⁴Nd ratio in these meteorites. The majority of the Atacama meteorites regardless of their weathering degrees have their REE compositions and ɛNd affected by terrestrial contamination. Both ¹⁴⁷Sm/¹⁴⁴Nd ratio and ɛNd values show no straightforward relationship with weathering degree. However, in both cases the samples with the highest negative isotopic disturbances are H chondrites from the Atacama and Lut deserts. In addition, Ba concentration shows a negative correlation with ¹⁴⁷Sm/¹⁴⁴Nd ratio. Care must be taken into account while dealing with samples collected from hot deserts, even fresh-looking ones.

陨石落入地球后，会经历风化。在这项系统研究中，我们评估了来自南极寒冷沙漠，阿塔卡马（智利）和卢特（伊朗）热沙漠的普通球粒陨石的痕量元素组成，重点是稀土元素（REE）。我们的数据证实，陨石在炎热沙漠中的陆地风化改变了其痕量元素（Sr，Ba，REE，Hf，Th和U）的浓度。但是，大多数南极样品的风化作用仅限于轻度的Ba，REE，Hf和Th耗尽，在某些情况下还限于U富集。与南极陨石相比，相对于平均下降值，炎热的沙漠样品显示出更大的扰动和REE分级。我们测量了严重影响稀土元素组成的热沙漠陨石的Sm-Nd同位素组成。比率为¹⁴⁷ Sm / ¹⁴⁴ Nd和¹⁴³ Nd / ¹⁴⁴ Nd。测量结果显示，与来自卢特沙漠的样本相比，阿塔卡马样本的变化较大，而¹⁴⁷ Sm / ¹⁴⁴ Nd较低。与CHUR ¹⁴⁷ Sm / ¹⁴⁴ Nd值的偏差与风化引起的La / Lu分馏程度呈正相关。阿塔卡马沙漠和鲁特沙漠陨石的ɛNd值范围为-2.20至+1.61，宽于秋天的-1.07至+0.64范围。我们认为，由于风化过程中与土壤来源的地面成分混合而引起的主要Sm / Nd比的扰动可导致较低的¹⁴⁷ Sm / ¹⁴⁴这些陨石中的Nd比。无论其风化程度如何，大多数阿塔卡马陨石的稀土元素组成和ɛNd都受到陆地污染的影响。两个¹⁴⁷ SM / ¹⁴⁴的Nd比和ɛNd值显示出与风化程度没有直接的关系。但是，在这两种情况下，负同位素扰动最高的样品都是来自阿塔卡马沙漠和卢特沙漠的H球粒陨石。此外，Ba浓度与¹⁴⁷ Sm / ¹⁴⁴ Nd比呈负相关。处理从炎热的沙漠，甚至是新鲜沙漠中采集的样品时，必须小心谨慎。