Premium
Oceanic island basalts in ophiolitic mélanges of the C entral C hina O rogen: An overview
Author(s) -
Yang Gaoxue,
Li Yongjun,
Tong Lili,
Wang Zuopeng,
Wu Le
Publication year - 2017
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.2977
Subject(s) - seamount , geology , mafic , geochemistry , basalt , ophiolite , mantle plume , abyssal zone , subduction , peridotite , tectonics , paleontology , lithosphere , oceanography
We present an overview of the internal structure of the 10 ophiolitic mélanges in the Central China Orogen (CCO) with a focus on the geochemical character and tectonic evolution of the ophiolitic mélange‐related ocean island basalt (OIB) and mafic rock assemblages. The ophiolitic mélanges in CCO are generally complicated and usually consist of metamorphic peridotites (serpentinite), cumulates, gabbros, basaltic lavas (pillows), and abyssal radiolarian cherts. The ages of ophiolitic mélanges range from Mesoproterozoic to Carboniferous. The OIB‐type basalts and mafic rocks in CCO occur as tectonic blocks within the mélanges that are composed of limestones, radiolarian cherts, and turbidites, possessing formation characteristics of seamounts (oceanic islands/plateau). The mafic rocks in ophiolitic mélanges of CCO display uniform chondrite‐normalized rare earth element (REE) patterns with light REE enrichment and heavy REE depletion, no obvious Eu anomalies or negative Nb, Ta, and Ti anomalies, and primitive mantle‐normalized trace element patterns with significant large‐ion lithophile element enrichment, similar to those of modern OIB and the Hawaiian alkaline basalts. The OIB‐type basalts and mafic rocks are considered as accreted seamount fragments in an accretionary complex of CCO and may represent plume‐related magmatism within the Proto‐Tethys Ocean and Paleo‐Tethys Ocean. Our study provides further insights into the processes of multiple subduction and long‐lasting accretionary histories with seamounts in the CCO.