The oceanic substratum of Northern Luzon

Evidence from xenoliths within Monglo adakite (the Philippines)

Betchaida D. Payot*, Sebastien Jego, Rene C. Maury, Mireille Polve, Michel Gregoire, Georges Ceuleneer, Rodolfo A. Tamayo, Graciano P. Yumul, Herve Bellon, Joseph Cotten

*Corresponding author for this work

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

A 8.65 Ma adakitic intrusive sheet exposed near Monglo village in the Baguio District of Northern Luzon contains a suite of ultramafic and mafic xenoliths including in order of abundance: spinel dunites showing typical mantle-related textures, mineral and bulk rock compositions, and serpentinites derived from them; amphibole-rich gabbros displaying incompatible element patterns similar to those of flat or moderately enriched back-arc basin basalt magmas; and amphibolites derived from metabasalts and/or metagabbros of identical affinity. A single quartz diorite xenolith carrying a similar subduction-related geochemical signature has also been sampled. One amphibolite xenolith provided a whole-rock K-Ar age of 115.6 Ma (Barremian). We attribute the origin of this suite to the sampling by ascending adakitic magmas of a Lower Cretaceous ophiolitic complex located at a depth within the 30-35 km thick Luzon crust. It could represent an equivalent of the Isabela-Aurora and Pugo-Lepanto ophiolitic massifs exposed in Northern Luzon.

Original languageEnglish
Pages (from-to)276-290
Number of pages15
JournalIsland Arc
Volume16
Issue number2
DOIs
Publication statusPublished - Jun 2007
Externally publishedYes

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Keywords

  • Adakite
  • Dunite
  • Gabbro
  • Luzon crust
  • Ophiolite
  • The Philippines
  • Xenolith

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