Derivation of Hawaiian rejuvenated magmas from deep carbonated mantle sources: A review of experimental and natural constraints

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