The role of carbon-rich or carbonatitic melts as an important metasomatizing agent in the Earth's mantle is supported by direct and indirect evidence of their involvement, ranging from the presence of erupted carbonatitic lavas to metasomatic reactions documented in minerals and melt inclusions from mantle xenoliths. Carbonatite metasomatism in hot-spot settings, and more particularly in the mantle sources of rejuvenated Hawaiian lavas, has long been suspected. However, an unequivocal geochemical tracer of carbonated mantle sources in alkaline volcanic suites is still missing. We here examine high-quality major- and trace-element compositions of ~400 primitive Hawaiian lavas (MgO = 8.5–21 wt%, SiO₂ = 37–50 wt%) and associated xenoliths, focusing on those erupted during rejuvenated stages of activity of the Hawaiian hot spot, Pacific Ocean. The rejuvenated-stage alkaline lavas are the most enriched in volatile elements among the four-stage Hawaiian lavas. Our compilation shows that these rejuvenated-stage lavas range from melilite/nephelinite to transitional basalts and are characterized by low-Si and high-Na, -K and -Ca contents, along with the enrichment of REE, Th and Ba relative to K, Hf, Zr, Ti and Nb. Their trace-element systematics argues against derivation from a homogeneous lherzolitic or pyroxenitic source, regardless of the involvement of residual garnet or hydrous phases. Based on a comprehensive review of natural and experimental constraints on partitioning between carbonatites and mantle minerals and numerical simulations of open-system melting, we show that it is rather consistent with carbonatite metasomatism in their source. Variations in SiO₂, CaO, alkali contents and trace-element proxies such as Hf/Sm also specify temporal variations in the depth of melting and/or the respective contribution of lherzolites and pyroxenites in a hybrid (probably asthenospheric) source fluxed by carbonatitic melts. We suggest that this episode took place ≤4.2 Ma at temperatures and pressures in excess of 1100 °C and 2 GPa. The low-solidus carbonatite melts were likely generated following a time lag which allowed for cooling of the plume and likely derived from an ancient (>1Ga), recycled mantle, or lower mantle, source in the Hawaiian plume, in good agreement with Sr-Nd-Hf-Os isotope systematics and other chemical and mineralogical features of Hawaiian rejuvenated lavas and xenoliths. The identification of a deep carbonated mantle source for Hawaiian rejuvenated volcanic series is also in line with noble gas and light stable isotope systematics and suggests that the interaction between carbonatite melts and peridotites/pyroxenites may be a critical process explaining the compositional variability of many oceanic island magmas.

富含碳或碳酸岩熔体作为地幔中重要的交代剂的作用得到了它们参与的直接和间接证据的支持，从喷发的碳酸岩熔岩的存在到矿物和地幔包体中的熔体包裹体中记录的交代反应。长期以来，人们一直怀疑热点环境中的碳酸岩交代作用，尤其是再生夏威夷熔岩的地幔来源。然而，碱性火山岩套中碳酸化地幔源的明确地球化学示踪剂仍然缺失。我们在这里检查了约 400 个原始夏威夷熔岩（MgO = 8.5–21 wt%，SiO ₂ = 37–50 wt%) 和相关的捕虏体，重点关注夏威夷热点太平洋活动恢复阶段期间喷发的捕虏体。再生阶段碱性熔岩是夏威夷四阶段熔岩中挥发性元素含量最高的。我们的汇编表明，这些再生阶段的熔岩范围从黄长石/霞石到过渡玄武岩，其特征是低 Si 和高 Na、-K 和 -Ca 含量，以及相对于 K 的 REE、Th 和 Ba 富集， Hf、Zr、Ti 和 Nb。他们的微量元素系统学反对源自均质的锂辉石或辉石来源，无论是否涉及残留的石榴石或含水相。基于对碳酸盐岩和地幔矿物之间划分的自然和实验限制以及开放系统熔融的数值模拟的全面审查，我们表明它与碳酸盐岩交代作用的来源相当一致。SiO的变化₂、CaO、碱含量和微量元素替代物（如 Hf/Sm）也指定了熔融深度的时间变化和/或在碳酸岩熔体流动的混合（可能是软流圈）源中，辉长岩和辉石岩的各自贡献。我们建议这一事件发生在 ≤4.2 Ma，温度和压力超过 1100 °C 和 2 GPa。低固相碳酸盐熔体可能是在允许羽流冷却的时间滞后之后产生的，并且可能来自夏威夷羽流中的古老（> 1Ga）、循环地幔或下地幔源，与 Sr- Nd-Hf-Os 同位素系统学和夏威夷再生熔岩和捕虏体的其他化学和矿物学特征。