Mineral dust particles from different source regions typically have distinct Pb isotope ratios. Theoretically, Pb isotopic composition of terrigenous minerals isolated from open‐ocean sediments should allow for dust provenance reconstructions. However, Pb isotopes of terrigenous fractions of sediments have frequently been inconsistent with expected source region signatures. This study investigates the reason(s) for offsets between the Pb isotope values of the dust component in sediment cores and those expected from source regions with focus on changes in sediment composition, sediment age, and sediment processing for analysis. Pb isotope ratios from Pacific Ocean core‐top sediments show a general delineation of the Intertropical Convergence Zone (ITCZ). Isotope mixing models support these general trends, though similarity in Pb isotope ratios of disparate source regions makes constraining specific sources challenging. Pb isotope ratios in downcore samples varied on glacial/interglacial time scales, being less radiogenic during the last glacial maximum, suggesting either a weakened ITCZ or the addition of a new, less radiogenic, source to the system. Finally, Pb isotope ratios in some source region samples yielded different Pb isotope signatures in bulk source sample than in the insoluble terrigenous fraction of the source sample, indicating that differential mineral preservation within the terrigenous component in sediments may cause offsets from source signatures. Overall, while Pb isotopes show distinct basin‐scale variations, high‐resolution spatial reconstructions require tight age controls and consistency in analytical treatment if used to define ocean sediment source regions.

中文翻译：

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评估沉积碎屑中的Pb同位素作为太平洋中的尘埃示踪剂

来自不同来源区域的矿物粉尘颗粒通常具有不同的Pb同位素比。从理论上讲，从开放海洋沉积物中分离出的陆源矿物的Pb同位素组成应该可以进行粉尘物源重建。然而，沉积物陆源部分的铅同位素经常与预期的源区特征不一致。本研究调查了沉积物芯中粉尘成分的Pb同位素值与源区预期值之间存在偏移的原因，并着重于沉积物成分，沉积物年龄和沉积物处理过程的变化进行分析。太平洋核心顶部沉积物中的铅同位素比显示出热带辐合带（ITCZ）的总体轮廓。同位素混合模型支持这些总体趋势，尽管不同源区的Pb同位素比率相似，但限制特定源具有挑战性。下冰川样品中的铅同位素比率随冰川/冰川间时间尺度的变化而变化，在最后一次冰川最大时期的放射成因较低，这表明该系统的ITCZ减弱或增加了新的，放射成因较低的来源。最后，某些源区样品中的Pb同位素比与源样品的不溶性陆源级分相比，在散装源样品中产生的Pb同位素特征不同，这表明沉积物中陆源成分中不同的矿物保存可能导致源标志的抵消。总体而言，尽管铅同位素显示出明显的盆地尺度变化，