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The oceanic substratum of Northern Luzon: Evidence from xenoliths within Monglo adakite (the Philippines)
Author(s) -
Payot Betchaida D.,
Jego Sebastien,
Maury Rene C.,
Polve Mireille,
Gregoire Michel,
Ceuleneer Georges,
Tamayo Rodolfo A.,
Yumul Graciano P.,
Bellon Herve,
Cotten Joseph
Publication year - 2007
Publication title -
island arc
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.554
H-Index - 58
eISSN - 1440-1738
pISSN - 1038-4871
DOI - 10.1111/j.1440-1738.2007.00574.x
Subject(s) - geology , mafic , geochemistry , amphibole , basalt , ultramafic rock , xenolith , adakite , oceanic crust , diorite , subduction , petrology , quartz , paleontology , tectonics , zircon
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.