Recycled crustal melt injection into lithospheric mantle: Implication from cumulative composite and pyroxenite xenoliths

Hong Fu Zhang, Eizo Nakamura, Katsura Kobayashi, Ji Feng Ying, Yan Jie Tang

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

A rare composite xenolith and abundant cumulative pyroxenites obtained from the Mesozoic Fangcheng basalts on the eastern North China Craton record a complex history of melt percolation and circulation in the subcontinental lithospheric mantle. The composite xenolith has a dunite core and an olivine clinopyroxenite rim. The dunite is of cumulative origin and has a granular recrystallized texture and extremely low Mg# [100 Mg/(Mg + Fe) = 81-82] contents in olivines. The olivine clinopyroxenite contains larger clinopyroxene and/or orthopyroxene with a few fine-grained olivine and tiny phlogopite, feldspar, and/or carbonate minerals interstitial to clinopyroxene. The clinopyroxene has low Mg# (83-85). Compositional similarity between dunitic olivine and pyroxenitic one indicates a sequential crystallization of dunite and pyroxenite from a precursor melt. Pyroxenite xenoliths include olivine websterites and clinopyroxenites, both are of cumulative origin. Estimation of the melt from major oxides in olivines and REE concentrations in clinopyroxenes in these composite and pyroxenite xenoliths suggests a derivation from subducted crustal materials, consistent with the highly enriched EMII-like Sr and Nd isotopic ratios observed in the pyroxenites. Occurrence of phlogopite, feldspar and carbonate minerals in some xenoliths requires the melt rich in alkalis (K, Na), silica and volatiles (water and CO2) at the latest stage as well, similar to highly silicic and potassic melts. Thus, the occurrence of these composite and pyroxenite xenoliths provides an evidence for voluminous injection of recycled crustal melts into the lithosphere beneath the southeastern North China Craton at the Late Mesozoic, a reason for the rapid lithospheric enrichment in both elemental and isotopic compositions.

Original languageEnglish
Pages (from-to)1167-1186
Number of pages20
JournalInternational Journal of Earth Sciences
Volume99
Issue number6
DOIs
Publication statusPublished - Jan 1 2010

Keywords

  • Composite and pyroxenite xenoliths
  • Cumulates
  • Lithospheric mantle
  • North China Craton
  • Recycled crustal melt

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

Fingerprint Dive into the research topics of 'Recycled crustal melt injection into lithospheric mantle: Implication from cumulative composite and pyroxenite xenoliths'. Together they form a unique fingerprint.

  • Cite this