Spatial and temporal evolution of magmatic arcs: Geochemical diversity and tectonic controls

• Published in: Journal of South American earth sciences Vol. 144; p. 105037
• Main Authors: Maury, René C., Pallares, Carlos
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.09.2024
• Subjects: Continental arcs; Hydrous fluid metasomatism; Intra-oceanic arcs; Slab melting; TTG; Slab melting; Continental arcs; Intra-oceanic arcs; TTG; Hydrous fluid metasomatism
• ISSN: 0895-9811; 1873-0647
• DOI: 10.1016/j.jsames.2024.105037

We review the main petrologic and geochemical features of magmatic rocks from continental arcs compared to their intra-oceanic equivalents. Both types share a number of characteristics, including their typical HFSE-depleted incompatible element patterns and isotopic Sr, Nd, Pb and Hf features, intermediate between those of N-MORB and continental crust. They are thought to derive from the partial melting of the mantle wedge metasomatized by fluids emanating from the downgoing plate. They are dominantly hydrous fluids provided by the breakdown of amphibolites and antigorite serpentinites, but a significant role is attributed to felsic hydrous melts derived from oceanic metabasalts and associated sediments. The more enriched character of magmas from continental arcs with respect to those from intra-oceanic arcs is ascribed to their genesis from a less depleted mantle wedge in a milder thermal regime, to the enrichment of their source via subduction erosion of the continental margin, and finally to their contamination during ascent and storage within a thicker crust. •The main petrologic and geochemical features of magmatic rocks from continental and intra-oceanic arcs.•They share similar characteristics, including their typical HFSE-depleted incompatible element patterns and isotopic Sr, Nd, Pb and Hf features.•They have intermediate geochemical characteristics between N-MORB and continental crust.•They derive from the partial melting of the metasomatized mantle wedge.•Compared with intra-oceanic arc the continental ones are more enriched.