Slab melting boosts the mantle wedge contribution to Li-rich magmas

The lithium cycling in the supra-subduction mantle wedge is crucial for understanding the generation of Li-rich magmas that may potentially source ore deposition in continental arcs. Here, we look from the mantle source perspective at the geological processes controlling the Li mobility in convergen...

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Published in:Scientific reports 2024-07, Vol.14 (1), p.15168-14, Article 15168
Main Authors: Schettino, Erwin, González-Pérez, Igór, Marchesi, Claudio, González-Jiménez, José María, Grégoire, Michel, Tilhac, Romain, Gervilla, Fernando, Blanco-Quintero, Idael F., Corgne, Alexandre, Schilling, Manuel E.
Format: Article
Language:English
Subjects:
704/445/209
704/445/210
704/445/330
704/445/431
Basalt
Crystallization
Dehydration
Earth Sciences
Geochemistry
Humanities and Social Sciences
Lithium
Melting
multidisciplinary
Science
Science (multidisciplinary)
Sciences of the Universe
Trace elements
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Summary:The lithium cycling in the supra-subduction mantle wedge is crucial for understanding the generation of Li-rich magmas that may potentially source ore deposition in continental arcs. Here, we look from the mantle source perspective at the geological processes controlling the Li mobility in convergent margins, by characterizing a set of sub-arc mantle xenoliths from the southern Andes (Coyhaique, western Patagonia). The mineral trace element signatures and oxygen fugacity estimates (FMQ >  + 3) in some of these peridotite xenoliths record the interaction with arc magmas enriched in fluid-mobile elements originally scavenged by slab dehydration. This subduction-related metasomatism was poorly effective on enhancing the Li inventory of the sub-arc lithospheric mantle, underpinning the inefficiency of slab-derived fluids on mobilizing Li through the mantle wedge. However, major and trace element compositions of mantle minerals in other xenoliths also record transient thermal and chemical anomalies associated with the percolation of slab window-related magmas, which exhibit an “adakite”-type geochemical fingerprint inherited by slab-derived melts produced during ridge subduction and slab window opening event. As these melts percolated through the shallow (7.2–16.8 kbar) and hot (952–1054 °C) lithospheric mantle wedge, they promoted the crystallization of metasomatic clinopyroxene having exceptionally high Li abundances (6–15 ppm). Numerical modeling shows that low degrees (
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-024-66174-y