Nature Communications (May 2024)

A HIMU-like component in Mariana Convergent Margin magma sources during initial arc rifting revealed by melt inclusions

  • Xiaohui Li,
  • Osamu Ishizuka,
  • Robert J. Stern,
  • Sanzhong Li,
  • Zhiqing Lai,
  • Ian Somerville,
  • Yanhui Suo,
  • Long Chen,
  • Hongxia Yu

DOI
https://doi.org/10.1038/s41467-024-48308-y
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 11

Abstract

Read online

Abstract Compositions of island arc and back-arc basin basalts are often used to trace the recycling of subducted materials. However, the contribution of subducted components to the mantle source during initial arc rifting before back-arc basin spreading is not yet well constrained. The northernmost Mariana arc is ideal for studying this because the transition from rifting to back-arc spreading is happening here. Here we report major and trace element and Pb isotopic compositions of olivine-hosted melt inclusions from lavas erupted during initial rifting at 24°N (NSP-24) and compare them with those in active arc front at 21°N and mature back-arc basin at 18°N. NSP-24 high-K melt inclusions have highly radiogenic Pb compositions and are close to those of the HIMU end-member, suggesting the presence of this component in the magma source. The HIMU-like component may be stored in the over-riding plate and released into arc magma with rifting. HIMU-type seamounts may be subducted elsewhere beneath the Mariana arc, but obvious HIMU-type components appear only in the initial stages of arc rifting due to the low melting degree and being consumed during the process of back-arc spreading.