Mantle heterogeneity has a first-order control on the petrological and geochemical differences of erupted mafic lavas worldwide. Because of their contrasted distributions between mantle phases, First Row Transition Elements (FRTEs) have been considered potential lithological tracers. Using a combination of published data on natural and experimental samples and new high-precision analyses on a variety of pyroxenite samples, we investigated the parameters that control FRTE partition (Ds) and exchange (K_Ds) coefficients between common mantle minerals. We demonstrate that mineral-clinopyroxene exchange coefficients are independent of composition and temperature and that coefficients obtained from natural samples can be accurate as long a sufficiently high number of compositionally diverse samples are considered, making them reliable input parameters in mantle melting models. As a proof of concept, we used the exchange coefficients determined from natural mantle lithologies in this study, along with published experimental clinopyroxene/melt partitioning coefficients, to perform simple inverse modeling on two basalt suites from the Western Volcanic Zone in Iceland and Samoa, selected for their contrasted Mn/Fe and Zn/Fe ratios. Our results show that a given FRTE ratio in basalt can be explained by a large range of modal proportions in the source. However, when combined, FRTE ratios become a powerful tool to constrain the nature of the source.

地幔非均质性对全球喷发镁铁质熔岩的岩石学和地球化学差异具有一级控制作用。由于它们在地幔相之间的对比分布，第一排过渡元素（FRTE）被认为是潜在的岩性示踪剂。结合天然和实验样品的已发表数据以及对各种辉石岩样品的新的高精度分析，我们研究了控制 FRTE 分区 ( D s) 和交换 (K _Ds) 常见地幔矿物之间的系数。我们证明了矿物-单斜辉石交换系数与成分和温度无关，只要考虑到足够多的成分不同的样品，从天然样品中获得的系数就可以是准确的，这使得它们成为地幔熔融模型中的可靠输入参数。作为概念验证，我们在本研究中使用了从天然地幔岩性确定的交换系数，以及已发表的实验单斜辉石/熔体分配系数，对来自冰岛和萨摩亚西部火山带的两个玄武岩套件进行简单的反演建模，选择因为它们对比的 Mn/Fe 和 Zn/Fe 比率。我们的结果表明，玄武岩中给定的 FRTE 比率可以用源中的大范围模态比率来解释。