Advances in Earth Science ›› 2005, Vol. 20 ›› Issue (11): 1234-1242. doi: 10.11867/j.issn.1001-8166.2005.11.1234

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Nb-ENRICHED BASALT: THE PRODUCT OF THE PARTIAL MELTING OF THE SLAB-DERIVED MELTMETASOMATIZED MANTLE PERIDOTITE

ZHANG Haixiang; ZHANG Boyou; NIU Hecai   

  1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640,China
  • Received:2005-03-04 Revised:2005-07-04 Online:2005-11-25 Published:2005-11-25

ZHANG Haixiang;ZHANG Boyou;NIU Hecai. Nb-ENRICHED BASALT: THE PRODUCT OF THE PARTIAL MELTING OF THE SLAB-DERIVED MELTMETASOMATIZED MANTLE PERIDOTITE[J]. Advances in Earth Science, 2005, 20(11): 1234-1242.

Nb-enriched basalt is a kind of arc basalt that has special geochemical characteristics. It is silicasaturated with high Na2O contents and differs from the typical arc basalt by the extremely high Nb (>7×10-6), TiO2 (1%~2%) and P contents with HFSE enrichment. In the primitive mantle-normalized trace element spider diagram, Nb-enriched basalts show weakly negative (sometime positive) Nb, Ta anomalies. The primitive mantle-normalized La/Nb ratios of the Nb-enriched basalts are smaller than 2 (but smaller than 0.7, occasionally). It is derived from the partial melting of mantle peridotite metasomatized by slab melts. Since Nbenriched basalts and adakites are the direct products of subducted oceanic slab, the characteristics of magma activity and interaction between slab melts and mantle wedge can be demonstrated by the studies of this association and the nature of the relative fluids and melts.

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